Topic: Two 12V in parallel vs. two 6V in series Posted By: bamaram2002 on 08/15/06 11:51am Plan on doing a fair amount of dry camping this fall, including Bristol and Talladega races. Right now, I only have a single 12V battery in the HTT and want to increase the length of time I can get out of my battery power. I have a second 12V deep-cycle battery sitting here. Which leads me to the question.... I've seen where people replace a single 12V with two 6V in series to increase the amps. How much more advantageous is that than if I put two 12V in parallel? Mike, Michele, Hannah (13) and Elijah (10) 2002 Dodge Ram 1500 QuadCab 2003 KZ Coyote 23CT Family Travel Photo Album Posted By: DSR on 08/15/06 11:54am First, Hopefully your two batteries are about the same age. We had two group 24 12-volt batteries and later switched to two 6-volt golf cart type batteries. The two 6-volt batteries go MUCH longer between charges than the 12 volt batteries did. 2500HD D/A CC 4X4 FR TT Posted By: Jim M. on 08/15/06 12:09pm There is not much advantage to two 6-volts in series over two 12-volts in parallel. The main advantage is cost, due to the cost competitiveness of 6-volt golf cart batteries. Golf cart batteries are "true deep cycle" batteries with thick lead plates that are more tolerant of deep discharge and they provide up to 500 recharge cycles. If you already have another 12-volt battery, I would use it. If the batteries are different ages, it is advisable to use them one at a time and keep one terminal the unused battery disconnected. This will help keep the weaker battery from discharging the stronger battery. 2000 Jayco Eagle 314BHS TT 1999 Chevy K3500, 4X4, Crew-cab, Dually, 7.4L (454 cu.in.) Yamaha EF2800i Generator WAR EAGLE!! Posted By: willald on 08/15/06 12:15pm This is a subject that draws a lot of debate on here. Its impossible to answer your question, the way you asked it. There are all different sizes/types of 12 volt batteries, depending on what kind you have, they may or may not have more staying power than a good pair of 6 volt batteries in series. Generally speaking, though, you do typically get better 'bang for your buck' ($$ per amp-hour), with a pair of 6 volters in series. That, and with 6 volt batteries, you are more assured of getting TRUE deep-cycle batteries, intended for what you're using them for. That may or may not be the case, when you buy 12 volt batteries. I would higly recommend a pair of 6 volters in series. Get you a pair of them from Sam's for $50 each, or if you really want the best, get you a pair of Trojan golf cart 6 volt batteries, for 'bout $70 each. That'll keep you going for several days, as long as you're careful. Will and Cheryl 2021 Newmar Baystar 3014 on F53 (7.3 V8) Chassis ("Brook") 2018 Jeep Wrangler JK ("Wilbur") Posted By: relliott on 08/15/06 12:18pm The way to get more battery use is to increase amp-hour capacity. Whether you use two 12 volt or two 6 volt batteries, you need to look at the total amp hours available. ALthough I prefer the design of the 6 volts golf cart batteries, it's possible that you could find two 12 batteries with more amp hour capacity. EMCM(SS) Retired US Navy 1997 Fleetwood Flair Class A Motorhome. Model 31Q 2003 Dodge Ram 2500, Cummins Diesel, Auto Trans, Quad Cab, Laramie Package  Posted By: time2roll on 08/15/06 12:32pm If you have two 12v use them. Worry about 6 vs 12 when you replace both. Besides I thought everyone ran generators 24/7 at the races. For a few beers you could probably plug into your neighbors gen for charging batteries. 2001 F150 SuperCrew 2006 Keystone Springdale 249FWBHLS 675w Solar pictures back up Posted By: 2oldman on 08/15/06 01:03pm 4 pages of discussion:12v vs 6v batteries Posted By: bill h on 08/15/06 09:20pm RJgonfshin wrote: But even 8 pages of discussion is not going to change the fact that for a given physical size/weight of battery, there is not a dimes worth of difference between 6v or 12v when it comes to amp hour capacity. Now if you're talking value for the buck, it has been reported many times that the 6'ers have better longivity than the 12's, especially when abused. Show Yup. I suspect that they build the golf cart batteries heavier because of the customers they have and the use they get. I also suspect there is a reason golf cart manufacturers design for 6 volt batteries. NOTE: Any incorrect spelling is intentional to prevent those annoying popups. 84 Barth 30Tag powered by HT502/Thorley/Weiand etc, Gear Vendors OD. Siamese Calvin and Airedale Hobbes, 4WD Toyota toad Posted By: coloradodave on 08/15/06 09:26pm About the only down side I can see to the two 6V route is if one dies, you are out of luck as your systems wont run on just 6V. If one 12V dies, you still have one good 12V battery that will run your systems. But since you have two 12's use them til they drop. '04 Coachmen Mirada 300QB DH & DW DS & DD 2 dogs Posted By: Bubby's RV on 08/15/06 09:46pm Battery rules: If you have two Gr 24 12-volt batteries at 85 amp-hours each, in parallel you will have 170 amp-hours. If you have two Gr 27 12-volt batteries at 105 amp-hours each, in parallel you will have 210 amp-hours. If you have two Gr 27 12-volt batteries at 115 amp-hours each, in parallel you will have 230 amp-hours. If you have two 6-volt batteries at 220 amp-hours each, in series you will have 220 amp-hours. That explains why, when going from two 12-volt batteries to two 6-volt batteries, some people get more amp-hours and some don't. If a 6-volt battery weighs 65 lbs and a Gr 27 battery weighs 65 lbs, the plates on the 6-volt battery will be thicker because there are half as many. Thicker plates have more longevity. You can save money by using the good batteries you have rather than buying new ones. When they wear out, then buy new batteries. John, Winnebago Minnie 24V Posted By: Houndog101 on 08/15/06 12:42pm smkettner wrote: If you have two 12v use them. Worry about 6 vs 12 when you replace both. Besides I thought everyone ran generators 24/7 at the races. For a few beers you could probably plug into your neighbors gen for charging batteries. This is the way to go, being as you already have the 2 batterys,,how do you charge them, and as stated the weaker one will pull down the stronger...have fun,, wish I could go,, love Nascar... 98 Pace Arrow Vision,F53, 37', 2 slides, Gibson, TransCommand Breed, raise, show Bloodhounds Posted By: bamaram2002 on 08/15/06 02:02pm Thanks everybody. Based on several responses, I'll go with the two 12V for now since its what I have on hand. Then when its time to replace them I'll switch to 6V. As for generators, I was hoping to get by without one if possible - all I have is a big, heavy, NOISY Coleman powermate and didn't want to have to lug it along, much less listen to it (not that there won't be enough of them nearby). Posted By: RJgonfshin on 08/15/06 02:09pm But even 8 pages of discussion is not going to change the fact that for a given physical size/weight of battery, there is not a dimes worth of difference between 6v or 12v when it comes to amp hour capacity. Now if you're talking value for the buck, it has been reported many times that the 6'ers have better longivity than the 12's, especially when abused. Rich ' 98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, Oly Catalytic Heat, hauling 2 Bent Bikes and sometimes towing a Tracker F&S boat. Posted By: TurnThePage on 08/15/06 02:24pm The design of my trailer tongue made my mind up for me. Two 6V will fit quite nicely in their boxes. Two equivalent 12V will not. 2015 Ram 1500 2004 Pioneer 18T6 Posted By: ktmrfs on 08/15/06 10:19pm relliott wrote: The way to get more battery use is to increase amp-hour capacity. Whether you use two 12 volt or two 6 volt batteries, you need to look at the total amp hours available. ALthough I prefer the design of the 6 volts golf cart batteries, it's possible that you could find two 12 batteries with more amp hour capacity. try to see the A/H at something other than a 20 hour rate as well (very low current draw 5 amps or less) . Many batterys have a A/H rating that drops drastically with increased current. You may find the A/H at current of 15-20 A is much less than the A/H at a lower draw. A good deep discharge battery has an A/H rating that holds up under high current draw used by RV's. Many good Deep discharge batteries (12V and 6V) such as trojan list the A/H at a 20 hour rate and at different currents. If it only list A/H at a 20 hour rate, be leary, you may be disappointed. 2011 Keystone Outback 295RE 2004 14' bikehauler with full living quarters 2015.5 Denali 4x4 CC/SB Duramax/Allison 2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son! Posted By: enahs on 08/15/06 10:19pm From the research I've done, it seems that you can't find 12 volt batteries that parallel to the amp hours the best 6 volt batteries in series will give — and there is a dime's worth of difference, especially if you are dry camping (which is all we do). I don't have room for the tall 6 volt golf cart batteries, so I've gone with series 30 AC-Delcos (which I've had very good luck with. As I recall, two of them give me 360 amp hours. The only need to run the generator comes with running the furnace — a real amp hog. Being very stingy with the electricity and using the Coleman lantern and no furnace, we have gone a week and still had battery — no generator (in a unit before the draw of safety sensors). '07 Chevy 3500 Dooley, CC, LT3, D/A Posted By: RJgonfshin on 08/16/06 12:49am Quote: From the research I've done, it seems that you can't find 12 volt batteries that parallel to the amp hours the best 6 volt batteries in series will give — and there is a dime's worth of difference, especially if you are dry camping (which is all we do). I don't have room for the tall 6 volt golf cart batteries, so I've gone with series 30 AC-Delcos (which I've had very good luck with. As I recall, two of them give me 360 amp hours. ------------------------------------------------------------------- Maybe I'm misunderstanding,........I thought you are saying that the 6v have more capacity than 12v, but if you have 2 12'ers at 360 AH's, you are not going to find 2 6v golf cart batteries that have anywhere near that much capacity. Like I said before, for a given size or weight, the difference in capacity between 6 & 12 is not worth talking about. But if you want to believe otherwise, you won't be the first. Posted By: bill h on 08/16/06 10:28am Bubby's RV wrote: Battery rules: If a 6-volt battery weighs 65 lbs and a Gr 27 battery weighs 65 lbs, the plates on the 6-volt battery will be thicker because there are half as many. Thicker plates have more longevity. Well put, Bubby. That says it all. . Posted By: Redapple on 08/16/06 11:22am The biggest downfall of the 6V setup is if one battery goes bad, you be in trouble, whereas if one 12v goes bad, you still have one 12v to work from. Bill 2006 Damon Daybreak 32ft 2007 Honda Accord Hybrid Posted By: TurnThePage on 08/16/06 01:07pm Redapple wrote: The biggest downfall of the 6V setup is if one battery goes bad, you be in trouble, whereas if one 12v goes bad, you still have one 12v to work from. Bill Though this is technically true, I don't think it would work that way for most people. How many of us bring along some kind of volt meter and regularly check the batteries? Out of that group, how many would understand that a cell went bad in one battery thus bringing the other battery to it's knees also. I think the only people that would be safe are the ones that keep their 12v batteries separated from the very beginning, and switch between them. On top of that just how often does a cell go bad in a 6v battery? I've never heard of one. And further, even if a 6v battery did go bad, a person could always use their tow vehicle battery as a backup. Posted By: enahs on 08/16/06 02:15pm Rich, the Trojan 125, 6 volt will give 488 a/h as compared to my two Delcos that deliver 360 together. When dry camping, that is a significant difference if you can fit them into your rig. Larger Trojan 6 volt batteries (T 145) give even more. In my view, the best approach is to use the golf cart batteries in high a/h ratings (or go with the two 12 volt batteries for insurance if the 6 volt batteries one selects give no more than the two 12s you would select). That is, all things being even (by virtue of one's selection), go with the 12s. But it does not have to be even. Posted By: ktmrfs on 08/16/06 03:49pm enahs wrote: Rich, the Trojan 125, 6 volt will give 488 a/h as compared to my two Delcos that deliver 360 together. When dry camping, that is a significant difference if you can fit them into your rig. Larger Trojan 6 volt batteries (T 145) give even more. In my view, the best approach is to use the golf cart batteries in high a/h ratings (or go with the two 12 volt batteries for insurance if the 6 volt batteries one selects give no more than the two 12s you would select). That is, all things being even (by virtue of one's selection), go with the 12s. But it does not have to be even. two t 125's in series give 240A/H. AH don't add when batteries are used in series. Posted By: enahs on 08/16/06 04:40pm Perhaps I am misreading specs or using specs that do not compare. However, the Trojan site indicates that the T-125 gives 488 minutes at 25 amps. My two Delco 30s give 2.8 hours at 25 amps. So two of them will give 5.6 hours at 25 amps — that's 336 minutes. Yes, I am aware that the parallel wiring adds minutes and the series that must be used with 6 volt batteries does not add minutes. So the Trojans would appear to have a 152 minute advantage over the Delcos. If there is something wrong with my numbers, I'll be grateful for a correction. I consider a 25 amp draw to be fairly large if one is managing electrical use carefully — especially not running the furnace. Thus, the Trojans would give a lot of dry camping capability if power use is frugal. But the Delcos are not bad and have the advantage of no water to monitor or add. Posted By: Redapple on 08/16/06 04:48pm enahs wrote: My two Delco 30s give 2.8 hours at 25 amps. So two of them will give 5.6 hours at 25 amps — that's 336 minutes. Are you saying that you have two (2) Delco's in parallel, and you are going to series parallel in two more for a total of four(4)? Thats the way I read it, please clarify... Bill Posted By: ktmrfs on 08/16/06 05:39pm enahs wrote: Perhaps I am misreading specs or using specs that do not compare. However, the Trojan site indicates that the T-125 gives 488 minutes at 25 amps. My two Delco 30s give 2.8 hours at 25 amps. So two of them will give 5.6 hours at 25 amps — that's 336 minutes. Yes, I am aware that the parallel wiring adds minutes and the series that must be used with 6 volt batteries does not add minutes. So the Trojans would appear to have a 152 minute advantage over the Delcos. If there is something wrong with my numbers, I'll be grateful for a correction. I consider a 25 amp draw to be fairly large if one is managing electrical use carefully — especially not running the furnace. Thus, the Trojans would give a lot of dry camping capability if power use is frugal. But the Delcos are not bad and have the advantage of no water to monitor or add. Now I understand your comparison which is a valid comparison of run time. However, the 488 minutes @25 amps is not the same as 488A/H. A/H in this case is (488/60)*25 which is 200AH by the way the delco in parallel (assuming 12V) will probably run longer than 5.6 hours (not buy enough to make up the difference) since each contributes 12.5A to the load not 25, and generally as you decrease load amps the run time goes up more than linear. A valid comparison is the delco run time at 12.5A per battery vs the 6v @ 25A. However I have never seen a table showing the 12.5A for 12V batteries. Posted By: dclark1946 on 08/16/06 06:59pm bill h wrote: Bubby's RV wrote: Battery rules: If a 6-volt battery weighs 65 lbs and a Gr 27 battery weighs 65 lbs, the plates on the 6-volt battery will be thicker because there are half as many. Thicker plates have more longevity. Well put, Bubby. That says it all. How do you know that the plates are thicker and not twice as many? Cells incorporate plates in parallel to increase total area. Dick Dick & Karen Richardson,TX 2017 KZ Spree 263RKS 09 F250 V10 Posted By: TurnThePage on 08/16/06 11:20pm Isn't the higher total area concept used in starting batteries versus deep cycle batteries? Posted By: bill h on 08/17/06 11:49pm dclark1946 wrote: How do you know that the plates are thicker and not twice as many? Cells incorporate plates in parallel to increase total area. Dick Deep cycle batteries have much thicker plates "a deep cycle battery uses thicker plates". "deep cycle batteries have heavier and thicker plates" and so forth Posted By: dclark1946 on 08/18/06 05:49am These links add nothing to the 12V vs. 6 V discussion. The discussion was about 12 vs. 6V deep cycle batteries. I contend that a Trojan deep cycle 12V battery probably has the same type plates as a Trojan T105. Because the T105 is only 6V each cell has more parallel plates but not thicker. It is more plates in parallel that give the T105 more amp hours than an equivalent volume 12V battery. If you add a second high quality true deep cycle 12V battery in parallel you double the amp hour capacity and you end up with essentially the same capacity as two 6V T105s. You end up with the same plate area in either case. There is no magic in 6V batteries that makes them superior to 12V if the plate quality and area are the same. Now if you compare a Costco deep cycle 12V battery with a Trojan 6V that is not a fair comparison. Dick Posted By: on 08/18/06 06:34am The reliability aspects of the question are not easily addressed in detail because of confusing statistical mathematics but perhaps the following idealization will help. First lets agree that a 12V battery is equivalent to two 6V batteries in series. Put two 6V batteries in series in a box and the box becomes a 12V battery. So we are really asking whether we are safer in the long run having one or two 12V batteries. The chance that both of two 12v batteries have failed after a particular time has passed is surely less that the chance that one of them has failed. Therefore the chance that one of two has survived is greater than the chance that a single battery has survived. If you've two 12V batteries the chances are that one will fail before the other and you'll be able to limp home rather than being dead in the water; the importance of this depends on one's situation. I'm usually within a cellphone's reach of help if my DC system fails so I haven't taken much precaution against battery failure - but that's not true for everyone. It is possible to arrange batteries such that the failure of one does not destroy all. Dave 1980 Born Free 22' Class C (minus) - 1985 Honda Scooter Posted By: klenger on 08/18/06 07:34am It's pretty rare for any battery to totally and suddenly fail. Usually, their performance drops off over time, giving you a chance to replace them before being "stranded". I've been using my Trojan T-105 batteries for 5 years and they are still in good condition. Posted By: on 08/18/06 09:51am Here's some real data on battery failure modes. It shows that, at least for automotive batteries, about half of batteries removed from service failed completely (open circuit or short circuit). -fair use of copyrighted data- Unfortunately, BCI doesn't publish such data regarding deep cycle batteries. If the chance of a battery's random, complete failure is 50% in a given time period, the chance that at least one of two batteries is still operating is 75% at the end of that period. Dave * This post was edited 08/18/06 09:57am by * Posted By: liborko on 08/18/06 11:01am I think Bubby's RV said that rather well. Two 6V batteries at 65 lbs. each will give you 12V at 130lbs. While the 12V battery will still be only 65 lbs. Both will have 6 cells with 2V nominal per cell. But two 6V combination will be a lot bigger than the 12V one. Even if you combine two 12V batteries to match the Ah capacity, I still prefer the way the 6V batteries are constructed from the reliability point of view. While it is common for a cell to short out on 12V batteries, I never experienced that on 6V batteries. That is probably reason while 2x6V combination last much longer than two 12V in parallel. Posted By: bill h on 08/21/06 11:36pm dclark1946 wrote: The discussion was about 12V vs. 6V deep cycle batteries. I contend that a Trojan deep cycle 12V battery probably has the same type plates as a Trojan T105. Because the T105 is only 6V each cell has more parallel plates but not thicker. Dick Nope. The Trojan 6V T105 has much thicker plates than the 12V Trojan SCS200 of almost equal weight. A pair of T105s weighs 124 lbs and provides 225 amps at a cost of $168 A pair of SCS200s weighs 120 lbs and provides 230 amps at a cost of $230. The T105 can be cycled deeper due to its thicker plates and will have a greater cycle life. So, in an apples-to-apples comparison, or at least equal weight and amps of the same manufacturer's deep cycle batteries, the 6 volters can be cycled deeper, last longer and cost less than the 12 volters.. In my conversation with an engineer at Trojan today, we went over these numbers, and I asked why on earth people bought the 12 volt batteries. His reply was that many RVs came that way and they just continued, and many RVs (mine, for example) did not accommodate the taller 6V golf cart batteries well. And, many RVers are happy and well served with just one battery, since they do little or no dry camping. So, they are meeting the market, like every other business. EDIT: In a later conversation, he confirmed by suspicion that the thicker plates in a T105 do allow a higher charging rate than the thinner plate 12 volt batteries. They can take about 25 percent of rated capacity instead of the 10 to 13 percent rate quoted on their site. This is useful if you have a big enough charger, and can minimize generator run time, saving a little fuel, noise and CO production. * This post was last edited 08/24/06 12:02am by bill h * Posted By: YoDude9999 on 08/22/06 02:44am Plate thickness is related to longevity of the battery as a whole and has nothing at all to do with amp hour capacity. To double the amp hour capacity, the plate area must be doubled. This can be done by increasing the overall size of the plate to double the area, or, by doubling the number of plates of the same size. 6 volt and 12 volt batteries of the same physical size will have nearly the same number of plate in them. The only real difference between them is the number of cells. A 6 volt battery can very easily be made to produce 12 volts by simply dividing the existing number of plates equally between 6 cells instead of 3. Likewise a 12 volt battery can be made into a 6 volt battery by simply arranging the plates evenly between 3 cells. In either case, the battery contains the same amount of energy and it's always a trade off between voltage and amp hour capacity and is always balanced. When one value goes up, the other goes down. As far as cycling, thicker plates again, increase the longevity of the battery. Any battery can be deep cycled. Every cycle uses up some of the plates due to flaking off and sulfation. Batteries with thicker plates get used up at a slower rate simply because there's more plate material to start off with. A battery with thin plates can be cycled just as deep as one with thick plates, but the number of times this can be done is limited with batteries containing thin plates because they just simply wear out before a thick plate battery will. A 6 volt and a 12 volt battery with plates of identical thickness will have the same longevity as far as cycling if they are continually cycled to the same SOC. Find more info at DudesRv.com AC cooling at capacity? Test Your Rooftop AC What's inside a PD converter? GUTS what else? (Updated 10.02.06) Experiment: WFCO9845 Posted By: Javlin101 on 08/22/06 06:54am I had 2 12v deep cycle batt's and switch to 2 6v and would never go back. The 6v seem to last longer between charges and I can run more stuff longer than I ever could on the 12v. Now if you have true deep cycle 12v batt's like Trojans that is a different story. I run 2 of these in my fishing boat and they are great. Run the sonar, GPS & and tunes all day without running the engine and hardly puts a dent in them. Just my experience oh yay and If one of your 6v go bad and your 100's of miles from civilization you have a problem. However 6v can be purchase as easily as 12v almost anywhere. Jim Posted By: bryanl on 08/22/06 10:19am Any battery is a trade-off between capacity, longevity, and cost. If you look at the Trojan summary specifications table, you can see this for both 12v and 6v batteries. You have a choice between two or three batteries of the same size and voltage so you can choose the trade-off you want. This means all of the "talking to engineers" and "plate thickness" and so on is not at issue because the choice of battery covers larger ranges of capacity, longevity, and cost. They also tend to be amleiorated by the fact that parallel batteries pull less current and that means larger effective energy capacity and that balances out any serial battery cell size differential for more or less equivalent batteries. What is at issue is availability and the place to put them. In general, a good guideline is to get the heaviest and most cost effective properly rated for the intended service batteries you can find that will fit your battery compartment and wire appropriately. You will probably make much more of a difference in your battery's capacity, utility, and lifespan by your patterns of use, charging, and maintenance than in most other factors anyway. Bryan Posted By: YoDude9999 on 08/22/06 11:28am You can buy a 12 volt deep cycle battery anywhere. Every store in my town (almost a dozen where I live) has them in one form or another. There is only one store in this town that sells 6 volt batteries. It just happens to be the only store in town that can get Trojan batteries, which ironically is the same place I ordered a Trojan J150 from last week and should arrive today. As far as cost goes....we'll see as I haven't yet paid for it. Avaliability of 6 volt batteries is not as easy as some may make it out to be, and that's my experience and knowledge. Yo- Posted By: bill h on 08/22/06 06:44pm YoDude9999 wrote: Avaliability of 6 volt batteries is not as easy as some may make it out to be, and that's my experience and knowledge. Yo- Yeah, that's a drawback. Have you checked golf courses? They are likely to have a connection or may sell you a pair. They often buy them by the pallet, and will let you in on the savings. Are there any users of electric carts nearby? Posted By: A.C. guy on 08/22/06 06:48pm Jim M. wrote: There is not much advantage to two 6-volts in series over two 12-volts in parallel. The main advantage is cost, due to the cost competitiveness of 6-volt golf cart batteries.. Total Hogwash. Anyone that has tried the 2 6's vs 2 12's knows the 2 6's last much longer. AND the 6's definitely are not cheaper; but there are worth the cost. The key is the amphour ratings. the 2 6's with have almost double the amphour ratings of the 2 12's And now abide faith, hope, love, these three; but the greatest of these is love. 2007 Newmar Kountry Star 2006 Newmar Ventana 3531 2005 Monaco (Worst built product I ever owned) 2005 Coachman -1st Motorhome (lowest cost way to try this fulltime thing) Posted By: YoDude9999 on 08/22/06 07:32pm We have one (9 hole) golf course. They replace the batteries in all the golf cars all at the same time. I don't know how often they replace them. Their connection is the same place I ordered the J150 from. The store doesn't stock Trojan batteries, but they are a local distributor. All Trojan batteries are special order from this store. I called them today just after my last post to check on the status of my order. Apparently they got my order 'in' just fine, but the distributor they are supplied by didn't have the J150 in stock either. I was informed it should arrive next Tuesday before noon. We'll see. I'm not in a rush for it to get here and I actually figured it wouldn't show up when they originally said it would so I'm not greatly disappointed. The next closest larger city is 100 miles away and I can't see spending the money on the gas just for a new battery, especially considering the cost will likely be over $100 to start off with. Even if I had gone there looking for a Trojan, I'd have probably had to special order it anyway because that town is the distribution point for this store. Finding a pair of 6 volt batteries there would likely be much easier however, as I believe they have a Costco or Sam's there, but then there's the cost of gas again AND the cost of long distance phone calls just to locate them. Patience IS a virtue! Posted By: CA Traveler on 08/22/06 08:06pm Quote: the 2 6's with have almost double the amphour ratings of the 2 12'sBut that is only half the story. The 6's don't add the AH rating while the 12s double the AH rating. So not much difference between the two pairs. 2009 Holiday Rambler 42' Scepter with ISL 400 Cummins 750 Watts Solar Morningstar MPPT 60 Controller 2014 Grand Cherokee Overland Bob Posted By: bill h on 08/23/06 11:49pm MELM wrote: Also look at the warranties for their T-145 and J*** batteries. Lots of amp hours in a little bigger package, but 3 months replacement vs 18 months on a T-105. What does Trojan know about those batteries, and/or the users? The T145 is used in a heavy-duty floor sweeper, and gets real hard use, so the warranty is shorter. Posted By: YoDude9999 on 08/24/06 12:03am A 90 day limited warranty is not unusual for many items that cost hundreds of dollars, why should it be any different for a battery? Posted By: Tankerhank on 08/26/06 02:29pm Bubby's RV wrote: Battery rules: If you have two Gr 24 12-volt batteries at 85 amp-hours each, in parallel you will have 170 amp-hours. If you have two Gr 27 12-volt batteries at 105 amp-hours each, in parallel you will have 210 amp-hours. If you have two Gr 27 12-volt batteries at 115 amp-hours each, in parallel you will have 230 amp-hours. If you have two 6-volt batteries at 220 amp-hours each, in series you will have 220 amp-hours. That explains why, when going from two 12-volt batteries to two 6-volt batteries, some people get more amp-hours and some don't. If a 6-volt battery weighs 65 lbs and a Gr 27 battery weighs 65 lbs, the plates on the 6-volt battery will be thicker because there are half as many. Thicker plates have more longevity. You can save money by using the good batteries you have rather than buying new ones. When they wear out, then buy new batteries. Almost a good example, except there is not a 12 volt battery made that can equal the actual deep cycle ability or abuse tolerance of the 6vdc golf cart batteries run in a pair. You can slap two 12 volt batteries together but you can not draw power from them like you can golf cart batteries (at least not more than once or twice), they aren't designed for that kind of draw, not even them so-called "deep cycle marine/rv" type, run them below 50% a few times and best get your checkbook out. He will be buying new batteries either at the races or when he gets home. Hank 2007 Tundra DCLB 5.7 4X2 2005 Rockwood 8243S Posted By: MELM on 08/22/06 08:16pm YoDude9999 wrote: {snip}Plate thickness is related to longevity of the battery as a whole and has nothing at all to do with amp hour capacity. To double the amp hour capacity, the plate area must be doubled. This can be done by increasing the overall size of the plate to double the area, or, by doubling the number of plates of the same size. A bit misleading... The plate surface area determines the amount of current a battery can produce. The volume (or weight) of the plates that can be active in the chemical process determines the amp-hr capacity. My usual line is that you buy the energy storage by the pound. The "testimonial" posts usually leave out what 12 volt battery or batteries they replaced with 120 pounds of NEW golf car batteries - was it 40, 50 or ??? pounds that had been used and/or abused? Are they comparing raisins to grapes? Batteries are designed for a specific usage and maintenance, and that requires differences in plate chemistry, specific gravity, alloy composition, etc. We need to look at how we intend to use the RV batteries and then choose the ones that were built to most closely match our usage and maintenance. I am confident that most will say that it is bad to use a cranking battery for the RV house battery (notice, I didn't call it deep cycle). Yet it can easily be a very good choice for anyone that only uses the battery for running the slides and/or power jack, then immediately recharged via the TV or shore power. Less weight, lower cost, plenty of capacity and a better warranty (if you don't tell). With a good charger, you can get years of service from one. If you think it's wrong to use a cranking battery for RV service, why don't you have the same thoughts about using a battery designed to power a golf cart for RV service? Check Trojan's warranty - it's available on YoDude9999's site - for exclusion when used for a purpose it wasn't designed for... And a Search will show that it took some effort for MrWizard to get his defective golf car batteries replaced. Also look at the warranties for their T-145 and J*** batteries. Lots of amp hours in a little bigger package, but 3 months replacement vs 18 months on a T-105. What does Trojan know about those batteries, and/or the users? If you search and read a few hundred posts on battery problems, you'll see that folks buying new RV's often get "abused" "looks new" batteries with their new RV. It may have sat on the dealer lot with the batteries totally discharged for a long time, but they charged up enough to get through PDI. Some have found RV/Marine cranking batteries on their trailers. If not required to "perform", they can easily make it past a year with a little care. Many compare those batteries to a brand new pair of golf car batteries. Not a good comparison. Search, and you will find a few members who tell the whole story; including the change in their use and maintenance after the first batteries failed. I'm confident that a pair of group 27 deep cycle batteries and a pair of same brand golf car batteries will both last for several years if properly used and maintained for many boondockers. Then there are those that need 8 or 10 batteries to meet their usage needs... For bamaram2002 (if you're still around), go with what you have if they are in good shape. I'm sure they don't have the capacity of brand new batteries if they have any age on them, but you probably won't see the difference without an expensive battery monitoring system and a few trips to get some comparisons. You'll end up buying new battery boxes for the golf car batteries, so add that to the cost. Manage your usage, and charge them each day if you can. Do you have a good charger that will restore a fair amount of the energy you use in a couple of hours of charging? Posted By: YoDude9999 on 08/22/06 08:17pm A.C. guy wrote: Jim M. wrote: There is not much advantage to two 6-volts in series over two 12-volts in parallel. The main advantage is cost, due to the cost competitiveness of 6-volt golf cart batteries.. Total Hogwash. Posted By: dclark1946 on 08/22/06 08:57pm YoDude9999 wrote: A.C. guy wrote: Jim M. wrote: There is not much advantage to two 6-volts in series over two 12-volts in parallel. The main advantage is cost, due to the cost competitiveness of 6-volt golf cart batteries.. Total Hogwash. Wrong answer! If you don't understand the basic electrical fundamentals please don't offer opinions as facts. Those who point out that you don't add amp hours for 2 6V batteries in series do understand basic electrical fundamentals and are correct. There is no difference in amp hour capacity between two 6V batteries in series and 2 12V batteries if the total volume and plate quality are the same. Dick Clark Electrical Engineer Raytheon Posted By: JTee on 08/23/06 03:06am MELM wrote: Also look at the warranties for their T-145 and J*** batteries. Lots of amp hours in a little bigger package, but 3 months replacement vs 18 months on a T-105. What does Trojan know about those batteries, and/or the users? I am also bothered by Trojans warranty practice (or lack of), for the T-145 batteries. It is also interesting to note that Trojan rates the T-145 with a higher lifetime energy rating than the T-105. Doesn't make sense that the longer life rated battery would have a shorter warranty period. I suspect it is mainly market driven and is not a reflection on the quality of the battery. Why warranty a battery longer than you have to? I have (4)T-145s that are getting to be 5 years old that still have plenty of life left in them. They are great batteries if you can get by the initial cost and lack of warranty coverage. 2003 GMC Sierra 2500HD Duramax 2005 Everest 293P Trailair CenterPoint Suspension Posted By: bamaram2002 on 08/23/06 09:50am MELM wrote: ...For bamaram2002 (if you're still around), go with what you have if they are in good shape. I'm sure they don't have the capacity of brand new batteries if they have any age on them, but you probably won't see the difference without an expensive battery monitoring system and a few trips to get some comparisons. You'll end up buying new battery boxes for the golf car batteries, so add that to the cost. Manage your usage, and charge them each day if you can. Do you have a good charger that will restore a fair amount of the energy you use in a couple of hours of charging? Still here. Thanks. I went ahead with the two 12V bats for now. I'll see how they hold up this weekend at Bristol. It will be easy enough to reconfigure if I do decide to go with the 6V bats later. Posted By: Carolapf on 07/25/07 08:28pm goodness, all this detail. So if I want to stay on a battery for a night or two is there anything I can tell my dealer to do and increase the time I can run lights, fridge and pump aside of having judy one relatively new 12 volt battery? Should I have a spare in reserve, how do you keep that charged? Do you get a second thingy platform in front to hold it? Carola and still my dream boy Steve "> All 3 kids in college "> and us alone (enter romantic music) in our 2004 Starcraft Homestead 29 sks 2000 Excursion Limited V10 Posted By: Tankerhank on 07/25/07 09:13pm Carolapf wrote: goodness, all this detail. So if I want to stay on a battery for a night or two is there anything I can tell my dealer to do and increase the time I can run lights, fridge and pump aside of having judy one relatively new 12 volt battery? Should I have a spare in reserve, how do you keep that charged? Do you get a second thingy platform in front to hold it? I have done up a system on my RV that is designed for boondocking and when I boondock I want to be able to use the TV/surround sound, the water pump & lights (limited Microwave even) as I see fit for a week. I will share with you something that I found when out camping over weekends; my batteries will last the whole weekend doing those things. I have solar panels to re-charge the batteries but charting the battery usage daily I found that for a weekend I could get it done without the panels. I have 4 Trojan T-105s which offer a total of 4,000 watts (watts is watts no matter the voltage) before totally dead, now you don't want to run batteries down below 50% as a habit but these will survive it if only done occasionally. For what you are asking you could set your rig up with 4 of these and be good for a weekend of the usage you described, then charge them up good when you get home. A very good quality charger will keep the batteries healthy for a very long time. One of the biggest thing with batteries IS what they are designed to handle, whether it is 24v,12v or 6v. 2nd is how well the are maintained and charged to "actual" full charge. The battery charging systems that comes with RV suck (to be polite) and do not maintain a battery in the best of conditions. A FULLY charged 12v battery will read OVER 13 volts, a good charger will charge it up to 14v and then float it at 13v. You get yourself some good batteries (4 of 'em), not that "deep cycle" junk, but batteries designed to be abused - golf cart batteries (the T-105 Trojans) are just that and a good charger and you can have adequate power for the whole weekend to run your lights, frig, water pump, and TV. The batteries will be down some by end of the weekend but a good, quality charger will keep them fit as a fiddle and ready for the next weekend. To find out what your usage would be total up the watts you would use. To get watts get the amps each item draws multiply that by the 12v and then multiply each items total watts by the number of hours you would use it in a weekend then total all those up and you have your total of watts the batteries need to provide. Odds are from what you described you will be well under 2,000 watts for the whole weekend and the 4 T-105s can provide that. I paid $65 each for my T-105 Trojans just to give you an idea of pricing when you talk to your dealer (seen prices over $100 each) about setting this up should this appeal to you. All of it, including the big battery box and battery cables should be under $500 plus whatever labor he would charge. Hope this helps you. Posted By: dclark1946 on 07/25/07 10:05pm Bubby's RV wrote: Battery rules: If you have two Gr 24 12-volt batteries at 85 amp-hours each, in parallel you will have 170 amp-hours. If you have two Gr 27 12-volt batteries at 105 amp-hours each, in parallel you will have 210 amp-hours. If you have two Gr 27 12-volt batteries at 115 amp-hours each, in parallel you will have 230 amp-hours. If you have two 6-volt batteries at 220 amp-hours each, in series you will have 220 amp-hours. That explains why, when going from two 12-volt batteries to two 6-volt batteries, some people get more amp-hours and some don't. If a 6-volt battery weighs 65 lbs and a Gr 27 battery weighs 65 lbs, the plates on the 6-volt battery will be thicker because there are half as many. Thicker plates have more longevity. . Not so. You have more plates in parallel in a 6V battery of the same volume. That is why the amp hours are higher. Dick Posted By: MountainLife on 08/17/07 08:35am Ok so can someone explain or go over the usage of say 2 sets or 3 sets of 6v t105's used together 2 to make 12v in series right? then can you parrallel those with another set and another for 400 to 600+ amp hours? can anyone go over the benefits and extended time on a setup like that if it is even possible? Space is really not an issue thanks! Also would it be even better to go with say t125's or 145's with 260A/Hours if I used the t145's would that give me 780Amp Hours? are the benefits above and beyond the actual number 780? thanks! PS where the heck are you guys fidning these for $65-$75??? Posted By: bryanl on 08/18/07 01:52pm Tankerhank wrote: Yes sort of - but my comparison was to a "deep cycle" 12v battery they stuff in these things. And by comparsion durablity and longiviety of a "golf cart" battery knocks the stuffings out of those so called "deep cycle" 12V... and that ain't no myth. All the rest just keeps the air warm. that is why I referred to actual measure. The 'true deep cycle' is another myth as is the snide remarks about what "they stuff in these things" The actual measure, as by folks that make the batteries, and those that sell and support them is what is more likely to represent reality. As noted, if you want more capacity, get bigger and heavier batteries! But don't think there are magic bullets that will replace proper use and maintenance. Posted By: Tankerhank on 08/17/07 09:20am MountainLife wrote: Ok so can someone explain or go over the usage of say 2 sets or 3 sets of 6v t105's used together 2 to make 12v in series right? then can you parrallel those with another set and another for 400 to 600+ amp hours? can anyone go over the benefits and extended time on a setup like that if it is even possible? Space is really not an issue thanks! Also would it be even better to go with say t125's or 145's with 260A/Hours if I used the t145's would that give me 780Amp Hours? are the benefits above and beyond the actual number 780? thanks! PS where the heck are you guys fidning these for $65-$75??? $65 batteries? This outfit only sells in AZ and CA but here is the link just the same; http://www.hodgsoncorp.com/products/trojan.htm Battery in parallel and series? I think I sort of covered most this in an earlier post, but yes you have to series connect the 6 volt batteries to create a 12 volt output and yes after that you parallel connect them to add more amp/hours "useable power". With my setup I have 4 T-105s, two connected in series for the 12 volts and then that group connected in parallel with a second series connected group for more amp/hours. The T-105 is somewhere around 200 amp/hour, with the two groups connected in parallel I get 400 amp/hours (if you wanted to run the batteries dead). Keeping things conservative that give me about 4000 watts of power of which I consider 2000 watts useable so as not to run the batteries below 50% (for the health of the battery over time), with the solar panels I never reach that low but as example for running on just batteries for a weekend it works. If you needed/wanted more amp/hours you need only add more series groups to the parallel setup thereby increasing your amp/hours by 200 each time (I know they are rated at more (220) but I stay conservative on all my figures). To figure what you will be using for power convert all your items into watts (watts are watts no matter so that is easiest to work with). volts X amps = watts. Total up your lights, water pump, radio, furnace, TV, Microwave (?) and so on that you will be using, taking their voltage times their rated amps of draw then multiply that by the number of hours (or fraction thereof) that you will use that item each day. Once you have your total you now know how many watts of power the batteries need to provide for a day, multiply by the number of days will give you your total power draw. If you do not want to abuse the batteries to improve they longiviety don't draw them down below 50%. Now you can figure how may series groups you need to hook in parallel to power your needs. The benefit of using series connected 6 volt "golf cart" batteries is durablity and longiviety of the batteries. A 12v "deep cycle" battery will be so much "trash at the curb", so to speak, if you tried doing to them what you can do to a golf cart battery. The extended time is in your total amp/hours, and if space isn't an issue you could get quite wild and crazy. Finding a battery charger to handle it will be the big trick, same goes for adding solar panels on the roof for charging them all. I have two 135watt panels and live where there is lots of sunshine in the summer and I consider them marginal for handling things, but to date they keep the batteries in good shape, even when out for a week. I would prefer to have 4 of those panels$$$$$ Posted By: bryanl on 08/17/07 03:45pm Quote: can anyone go over the benefits and extended time on a setup like that if it is even possible? Space is really not an issue You won't get any significant benefits from how you configure your battery bank. Quote: The benefit of using series connected 6 volt "golf cart" batteries is durablity and longiviety of the batteries. This is a myth. See the various FAQ's at places like Az sunsolar. --- Durability and longevity are going to be enhanced more by proper maintenance, storage, and use than anything else by a long shot. The capacity of your battery bank is going to be determined by its size and weight more than any other factors. Simple addition of capacities in a bank is only a first order approximation. It is greatly influenced by the current draw. More batteries means more current sharing which means that the current draw profile from each battery is going to be significantly different from the usual 20 hour rate spec. (see the tech pages at smart guage for some good explanations of this). If you want your battery bank to last a long time without much trouble, size it so that you always discharge it between 10% and 50% (no more, no less as a general rule). Don't leave it in a discharged state more than a few days. Recharge promptly and fully with an intelligent 3 stage battery charger. When not in use for more than a couple of weeks, be sure to use an effective battery maintainer on it to keep it charged and healthy. Avoid exposing your battery bank and equipment to temperature extremes. Use batteries designed for the intended service. Posted By: Tankerhank on 08/17/07 04:58pm Quote: The benefit of using series connected 6 volt "golf cart" batteries is durablity and longiviety of the batteries. This is a myth. See the various FAQ's at places like Az sunsolar. --- Yes sort of - but my comparison was to a "deep cycle" 12v battery they stuff in these things. And by comparsion durablity and longiviety of a "golf cart" battery knocks the stuffings out of those so called "deep cycle" 12V... and that ain't no myth. All the rest just keeps the air warm. Posted By: time2roll on 08/17/07 05:19pm MountainLife wrote: Also would it be even better to go with say t125's or 145's with 260A/Hours if I used the t145's would that give me 780Amp Hours? are the benefits above and beyond the actual number 780? thanks! PS where the heck are you guys fidning these for $65-$75??? T145 is good... but look at the L16 for real power. You can buy a box to hold four L16 (or four GC2s) at www.alliedbattery.com The benefits of going bigger is just more power and more time before you need recharge. Also with larger batteries you will in effect discharge them slower giving even more amp hrs. And in the case of a large inverter you should have a minimum of 400 amp hrs. Trojan T105 for $75, good luck. Golf cart battery at Sam's about $65 and $75 at Costco. Costco just raised prices so if you can get some for $65 at Sam's before they raise prices jump on it. If you are going to connect more than four in parallel (eight 6v series parallel) I would suggest proper fuses between the batteries. Posted By: time2roll on 08/17/07 05:23pm Carolapf wrote: goodness, all this detail. So if I want to stay on a battery for a night or two is there anything I can tell my dealer to do and increase the time I can run lights, fridge and pump aside of having judy one relatively new 12 volt battery? Should I have a spare in reserve, how do you keep that charged? Do you get a second thingy platform in front to hold it? Don't throw away a good 12v to get two 6v. Just have the dealer add a similar 12v next to the existing and yes they will add a second thingy to hold it. Your existing charge system is fine for up to four batteries. Posted By: livingstonsn on 01/29/08 02:44pm We will be going on a 7-day dry camping trip with our Trail Cruiser at the end of March. We don't really care about running the microwave or a TV. We only care about the lights and furnace (if necessary). I already have a group 24 12V battery that's pretty new. My question is this: would an additional 12V (group 27, maybe) or 6V assembly connected to my current 12V be enought for a week with just lights, parasitic drain, and the occasional furnace? Thanks! Posted By: Tankerhank on 01/29/08 03:07pm livingstonsn wrote: We will be going on a 7-day dry camping trip with our Trail Cruiser at the end of March. We don't really care about running the microwave or a TV. We only care about the lights and furnace (if necessary). I already have a group 24 12V battery that's pretty new. My question is this: would an additional 12V (group 27, maybe) or 6V assembly connected to my current 12V be enought for a week with just lights, parasitic drain, and the occasional furnace? Thanks! Lot of variables there; how many watts does the furnace & other items use, how long do you plan on running each, what is the AMP/HR rating for the battery(s)? Then how far down do you plan on discharging the battery (s), some batteries handle a deeper discharge than others without ruining them. The golf cart batteries I use will handle a 50% discharge without damaging them, other batteries will only handle about an 80% discharge... lot of "depends" there. Obviously your furnance will be the big draw to consider. If you get your total watts you will be using and divide that into the total watts the battery can provide you will have your answer as to how long the battery (s) will provide power. Posted By: livingstonsn on 01/29/08 03:26pm Thanks! I'll have to wait 'till I get home to look all of that up. We don't do enough dry camping (a week at a time max between transit periods) to justify the cost of a generator or solar charger so I'm really trying to balance cost with utility. Posted By: Tankerhank on 01/29/08 03:31pm livingstonsn wrote: Thanks! I'll have to wait 'till I get home to look all of that up. We don't do enough dry camping (a week at a time max between transit periods) to justify the cost of a generator or solar charger so I'm really trying to balance cost with utility. Boondocking is just about all we do, I installed solar with the intent of not annoying the wild life with a generator *G*. Hope it all works for you. Posted By: livingstonsn on 01/29/08 03:34pm Tankerhank wrote: livingstonsn wrote: Thanks! I'll have to wait 'till I get home to look all of that up. We don't do enough dry camping (a week at a time max between transit periods) to justify the cost of a generator or solar charger so I'm really trying to balance cost with utility. Boondocking is just about all we do, I installed solar with the intent of not annoying the wild life with a generator *G*. Just out of curiosity, how many watts would be good for a solar charger? Posted By: Tankerhank on 01/29/08 03:46pm livingstonsn wrote: Just out of curiosity, how many watts would be good for a solar charger? There goes that depends thing again. If you want something to maintain your single 12v battery there are some ready made setups out there. If you want something to keep you going while out that gets involved to calculate. Even though we boondock I like my creature comforts - DVD/LCD w/surround sound, power enough to run the microwave to make popcorn (what's a movie without popcorn? *G*) normal lighting, water pump and such plus using the furnace from time to time. I am squeaking by with two 135w panels, I would love to have two more panels. Posted By: blkfe on 01/29/08 04:43pm A.C. guy wrote: Jim M. wrote: There is not much advantage to two 6-volts in series over two 12-volts in parallel. The main advantage is cost, due to the cost competitiveness of 6-volt golf cart batteries.. Total Hogwash. Huh? Posted By: Tankerhank on 01/29/08 05:13pm blkfe wrote: Huh? 12V batteries are like quarter horses, 6V batteries are like oxen... how's that for adding to the madness? *G* None of the "deep cycle" 12V marine batteries I have seen will actually handle a deep cycle discharge like a good old 6V golf cart battery. The 6V golf cart battery is made to be deep discharged, can do 50% day in and day out, the 12V battery will die an early death if you ran it down to 50% day in and day out. One Trojan golf cart battery is rated at 220 amp/hr, hooking two of them in series still only gives you 220 amp/hr but at 12V and in the world of watts that is 2640 watts. Watts is the universal language of power usage. A group 27 battery is around 100 amp-hr rated, two of them in parallel would give you 200 amp-hr or 2400 watts. The 6V golf cart batteries wins - mostly because of its ability to be worked hard and still give you lots of years of service. Posted By: RJsfishin on 01/29/08 10:38pm No one said the 6ers aren't a better bang for the buck overall, but if you are saying that they have more AH capacity, go tell somebody that will believe that BS ! Even a pair of WM's DC6 grp 27 batteries have have 230 AH's. Is that more than 220 or even 225 ? It's a draw,...believe it. I've had both. Rich '01 31' Rexall Vision, Generac 5.5k, 1000 watt Honda, PD 9245 conv, 300 watts Solar, 150 watt inv, 2 Cos 6v batts, ammeters, led voltmeters all over the place, KD/sat, 2 Oly Cat heaters w/ ox, and towing a 2012 Liberty, Lowe bass boat, or a Kawi Mule. Posted By: bryanl on 01/30/08 02:34pm Quote: None of the "deep cycle" 12V marine batteries I have seen will actually handle a deep cycle discharge like a good old 6V golf cart battery. interesting. the specifications don't show that. The failure analyses I have seen also do not support this (more than 80% of failures seem to be sulfation related). Typical RV use doesn't put this kind of stress on batteries, either, in general. If your RV battery bank is properly sized, you'll cycle it down 15% to 50% between charges. You will likely only do this 10 to 50 times a year. That isn't enough to warrant a traction battery. The key is that the typical RV/Marine battery is designed for typical RV service and getting some mythical battery rated for a non-typical RV service is probably something to be reserved for special cases. I think you may also find that 12v RV/Marine batteries can be a better bang for buck as a matter of source and scale of operation. There is also something to be said for parallel operation over serial in terms of increased available capacity due to reduced per battery loading and other factors. There is a reason most TT manufacturers providing 2 battery systems provide 12 v parallel configurations. There is also a reason why the diesel pickups use 12v parallel battery systems, too. Posted By: ben duarte on 01/30/08 05:40pm Quote---"There is also something to be said for parallel operation over serial in terms of increased available capacity due to reduced per battery loading and other factors." bryanl, could you explain that one? That is, the amps per pound of lead is the same, so it's the same loading, series or parallel. You mentioned other factors, what are those? Posted By: Matthew_B on 01/30/08 08:15pm bryanl wrote: There is a reason most TT manufacturers providing 2 battery systems provide 12 v parallel configurations. Yeah, because RV manufacturers are cheap, and the 12V batteries are the lowest upfront cost Quote: There is also a reason why the diesel pickups use 12v parallel battery systems, too. That's because they can put 1 battery in gas trucks and then put 2 of the very same batteries in the diesels. It is an example of economy of scale. Posted By: bryanl on 01/31/08 01:44pm Quote: That is, the amps per pound of lead is the same, so it's the same loading, series or parallel. You mentioned other factors, what are those? the jihad continues. sorry to see it. The fact is that weight is only one factor. Use profile can make a significant difference. It gets very interesting looking at how the arguments are disputed or supported. Conspiracy theories are always indicative and then when corporate greed gets in there, you really know you have something! (and they should go look under the hood sometime, ok?) But, back to the question. The key is Peukert. For those trying to figure things out, read through More on the effects of Peukert, capacity and energy drain, and Splitting battery banks The key is that "so it's the same loading, series or parallel" is true for energy from the batteries in a bank but not necessarily true for the current draw. In parallel, the current is divided and the voltage is shared. In series, the voltage is divided and the current is shared. Just that difference can create a significant difference in available energy capacity depending upon the energy use profile. The idea that "the amps per pound of lead is the same" is also interesting because it tends to discredit one of the arguments most often cited for 6v batteries being superior. I really wonder if the degree of vituperation I see on this topic is warranted by the significance of the issue. To me there is a significant discrepancy between those two. The attempts to censor Peukert seem to completely outweigh the significance of the idea in most of these battery discussions. Posted By: ben duarte on 01/31/08 03:44pm bryanl, let's look at your statement again. Quote---"There is also something to be said for parallel operation over serial in terms of increased available capacity due to reduced per battery loading and other factors." When you say parallel operation over serial, one must assume you mean the same total specified ahs and same peukerts. If so, there is no capacity difference, ie, pounds of lead. If you were to say you had one 12v battery and added a second in parallel then the capacity would more than double over that specified because of shared currents. But, anytime the total specified capacity is the same for series or parallel and peukerts is the same then shared currents don't get you anything because the ah for each parallel battery is half that of each serial battery. Half the capacity, half the current (shared), same loading. The links you provided say nothing about capacity advantage for parallel over series for the same specified total ahs with the exception of the link to capacity and energy drain which shows at the bottom of the page in the chart a 7.18 percent reduction, as an example, for both 100 and 200 ah batteries of peukerts of 1.1 over a theoretical 1.0 for 5 amp and 10 amp respectively which shows no gain for a parallel configuration. You reference to jihad is a bit misplaced. It is your battery myth regarding capacity gain with parallel over series that keeps the discussion going. Posted By: Kajtek1 on 01/31/08 03:54pm Matthew_B wrote: Quote: There is also a reason why the diesel pickups use 12v parallel battery systems, too. That's because they can put 1 battery in gas trucks and then put 2 of the very same batteries in the diesels. It is an example of economy of scale. Would the fact that nobody manufacture 6V engine starting batteries matter as well? Golf cart batteries have poor cranking amps. Posted By: Matthew_B on 01/31/08 07:53pm Kajtek1 wrote: Would the fact that nobody manufacture 6V engine starting batteries matter as well? Exide does. Posted By: time2roll on 01/31/08 08:23pm Six volt starting battery is getting harder to find. Isn't that an old VW battery? Even harder to find a six volt deep cycle / starting marine combo battery. Golf batteries are made for deep cycling in a golf cart, not much else. A good fit for an RV house battery IMO. Posted By: topflite51 on 01/31/08 08:46pm If that is the only choices, I will take the two 12V's in parallel over the two 6V's. If you are out in the middle of nowhere, something that is easily done here in NV, and one of the 6V's goes belly up, you loose the controls on your frig. If the same thing happens and you have two 12V's, you disconnect the defective one, and you still have a 12V to keep the frig running. If need be, you can charge it up using the generator. It happened to me, I now run two 12V's. Now if there is a 3rd choice of 4 batteries, I would run 4 6V's in series. ">David Just rolling along enjoying life w/F53 Southwind towing a 87 Samurai or 01 Grand Vitara looking to fish Simply Despicable "> Any errors are a result of CRS."> Posted By: Bobbo on 01/31/08 09:35pm This thread starting 8/15/06!!!!! 18 months and it is still being argued to death. Bobbo and Lin 2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6 2017 Airstream Flying Cloud 23FB Posted By: mike4947 on 01/31/08 10:18pm An FYI on 6 volt starting batteries. These were the defacto standard until late in the 1950's and in the early 1960's. Antique and classic car owners do still form a niche market for them and in the late 60's and 70's I made a good side living converting older auto's to 12 volt systems including, lights, gages, starters, and the then new alternators. For those wondering about diesel vehicles using 12 volt batteries it's because the availability of 12 volt starting batteries is so much greater and if they need a 24 volt starting system and 12 volt accessory (lighting/etc) it's an easier design with less wiring to worry about over time. blog.rv.net Your daily guide to the Open Road Subscribe to the daily digest They say you learn by your mistakes, in that case I must be a genius. Posted By: topflite51 on 02/01/08 02:10pm Bobbo wrote: This thread starting 8/15/06!!!!! 18 months and it is still being argued to death.It's winter! Posted By: bryanl on 02/01/08 11:20pm Quote: This thread starting 8/15/06!!!!! 18 months and it is still being argued to death. what that tells you is that there is a significant emotional investment in the ideas and issues discussed. That also shows in the manner of the arguments. It is very interesting that something as seemingly innocuous as this topic would have such an emotional component. As for the identical thing; start there and then double the load, think about what happens to the change of current in the components of the battery bank in different configurations. Posted By: ben duarte on 02/03/08 08:26am Quote---"As for the identical thing; start there and then double the load, think about what happens to the change of current in the components of the battery bank in different configurations." Losses increase. That's peukerts. If you were referring to current sharing in parallel accounting for mythical gain then it doesn't work. Compare cell to cell. A three cell six volt battery of equal lead to a six cell twelve volt battery has twice the lead per cell than the twelve volt. The twelve volt must see half the current of the six volt for the same current density, ie, amps per lead, equal 'stress'. Series or parallel all is equal. Same load profile same performance. Posted By: liborko on 02/03/08 12:29pm There is no difference in AMPEREHOURS between two 12V 110Ah batteries connected in parallel and two 6V 220Ah batteries connected in series. But because of the way 6V golf cart batteries are built, they seem to last longer according to most people who have them. By the way there is no such a thing as amperes per hour or AMPS/HOUR. There is amps and there is amphours(amps x hours). The first one is a current and the second one is a capacity(charge). Then there is watts and watthours. The first one is a power(Volts x Amperes) and the second one is energy(Volts x Amperes X hours). There is no watts per hour or W/h. When abbreviating Volt, Ampere, Watt, Henry, Hertz, Ohm, Tesla, Joule, Newton, Pascal, Celsius, Fahrenheit, Farad etc. always use capitol letter because these units are named after the people (scientists, physicists) who invented them. Kilo (k), milli(m) mega(M), giga(G), tera(T) are metric multipliers and m and M are not the same. Hour is h, Henry is H and Hertz is Hz. Amperehour is Ah, watthour is Wh, kilowatthour is kWh, megawatt is MW, milliwatt is mW, milliamp is mA. Posted By: RKW on 02/03/08 01:53pm I'm probably gonna get hooted and booed off this thread for asking this, but honestly I'm just trying to understand something ( besides, it's winter 1) Is it accurate to say that Peukert's Law explians the fact the higher the draw rate on a battery, the lower the apparent (i.e. usable) capacity? 2) Does connecting 2 batteries in series increase the Peukert exponent? 3) The Peukert exponent for my T-105s is 1.24. Assuming that remains the same when 2 are connected in series, is a battery bank with a P exponent of 1.24 significantly superior in some way to a battery bank with a P exponent of 1.27? I'm using 1.27 because that's seems to be the P ex of most Trojan 12 volt batteries. 4) If the answer to #'s 2 and 3 are no, why does Peukert's law belong in a discussion of 2-12V bats verses 2-6V bats? Ryan The wages of sin are death; but after they're done taking out taxes, it's just a tired feeling. Posted By: liborko on 02/03/08 02:31pm The Peukert Effect is a fact of life and it applies to all batteries regardless of voltage. Don't let it complicate your life. Some people on this forum give Peukert effect way too much attention. Just like fast charging does not get full use of a battery capacity, fast discharge does the same thing. Unless you are running high loads for extended periods of time Peukert Effect will have little effect in your daily life. Posted By: CROSSBOLT on 02/03/08 02:38pm This and 50 amp and 30 amp is always good for a long run.....I'm gonna use 2 6 volt golf cart batts when the two 12 volt interstates die.. Karl Posted By: John / Angela on 02/03/08 03:05pm Just some practical experience here. We would have loved to squeeze 4 X 6 volt trojans into our little Class C toad. Just couldn't make them fit. So we squeezed 3 X group 31 X 12 volt Trojan deep cycle batteries in. The results are significantly longer run times over the 3 X group 24 we originally had. We use them with an inverter system along with 200 watts of solar. We actually recently posted a review of our system here on our website. Some good reading and we are pleased with the results although we need to add another 120 watts of solar. Enjoy 2003 Revolution 40C Class A. Electric smart car as a Toad on a smart car trailer Life is not measured by the number of breaths we take but rather by the moments that take our breath away. Posted By: bryanl on 02/04/08 05:35pm Quote: Some people on this forum give Peukert effect way too much attention and elsewhere, and boy does it rile some folks, too. the fact is that there are many variables involved in getting the most from your batteries and use profile is one of the few where you have some control. Quote: But because of the way 6V golf cart batteries are built, they seem to last longer according to most people who have them. There are two points for caution here. All batteries are built the same way of the same materials with slight variations to suit a number of needs. This is why Trojan has several 6v. 8v. and 12v. battteries such as the T105 and T145 or the SCS200 and SCS220. It is not really accurate to think in terms of some single super battery. The studies of battery failures and returns tends to be a larger and more representative sample than the self selected sample here. The broader sample does not show that there is any battery that does much better than any other. Some 80% or so (depending upon source) of battery failures are sulfation related. That is very much dependent upon how you use and maintain the battery. Factors such as ruggedness are seldom involved in why an RV battery will last months or years. That is why some say batteries don't die, they are killed. Posted By: RKW on 02/04/08 11:27pm I found the following information about battery lifespans and battery construction interesting: The lifespan of a deep cycle battery will vary considerably with how it is used, how it is maintained and charged, temperature, and other factors. In extreme cases, it can vary to extremes - we have seen L-16's killed in less than a year by severe overcharging, and we have a large set of surplus telephone batteries that sees only occasional (5-10 times per year) heavy service that are now over 25 years old. We have seen gelled cells destroyed in one day when overcharged with a large automotive charger. We have seen golf cart batteries destroyed without ever being used in less than a year because they were left sitting in a hot garage without being charged. Even the so-called "dry charged" (where you add acid when you need them) have a shelf life of 18 months at most. They are not totally dry - they are actually filled with acid, the plates formed and charged, then the acid is dumped out. These are some typical (minimum - maximum) typical expectations for batteries if used in deep cycle service. There are so many variables, such as depth of discharge, maintenance, temperature, how often and how deep cycled, etc. that it is almost impossible to give a fixed number. Starting: 3-12 months Marine: 1-6 years Golf cart: 2-6 years AGM deep cycle: 4-7 years Gelled deep cycle: 2-5 years Deep cycle (L-16 type etc): 4-8 years Rolls-Surrette premium deep cycle: 7-15 years Industrial deep cycle (Crown and Rolls 4KS series): 10-20+ years Telephone (float): 2-20 years. These are usually special purpose "float service", but often appear on the surplus market as "deep cycle". They can vary considerably, depending on age, usage, care, and type. NiFe (alkaline): 5-35 years NiCad: 1-20 years Plate thickness (of the Positive plate) matters because of a factor called "positive grid corrosion". This ranks among the top 3 reasons for battery failure. The positive (+) plate is what gets eaten away gradually over time, so eventually there is nothing left - it all falls to the bottom as sediment. Thicker plates are directly related to longer life, so other things being equal, the battery with the thickest plates will last the longest. Automotive batteries typically have plates about .040" (40/1000") thick, while forklift batteries may have plates more than 1/4" (.265" for example in the Rolls-Surrette) thick - almost 7 times as thick as auto batteries. The typical golf cart will have plates that are around .07 to .11" thick. The Concorde AGM's are .115", The Rolls-Surrette L-16 type (CH460) is .150", and the US Battery and Trojan L-16 types are .090". http://www.windsun.com/Batteries/Battery_FAQ.htm Posted By: chuck4788 on 02/05/08 09:15am RKW (previous post) quoted some very good info on batteries that explains some of the differences between deep cycle and regular batteries. The capacity of a battery for deep cycle use is dependent on the amount of lead in the battery that can react with the acid. Deep cycle batteries use a thick porious plates. The Amphour capacity of a deep cycle battery is directly proportional to its weight, so when comparing AH capacities between batteries also check the weight to see if the label is lying. One advantage of 6 volt GC is the smaller package is easier to handle; e.g. one GC weighs aout 65# and two are equivalent to one 8D weighing 130#. RKW wrote: I'm probably gonna get hooted and booed off this thread for asking this, but honestly I'm just trying to understand something ( besides, it's winter 1) Is it accurate to say that Peukert's Law explians the fact the higher the draw rate on a battery, the lower the apparent (i.e. usable) capacity? Yes 2) Does connecting 2 batteries in series increase the Peukert exponent? NO 3) The Peukert exponent for my T-105s is 1.24. Assuming that remains the same when 2 are connected in series, is a battery bank with a P exponent of 1.24 significantly superior in some way to a battery bank with a P exponent of 1.27? I'm using 1.27 because that's seems to be the P ex of most Trojan 12 volt batteries. NO 4) If the answer to #'s 2 and 3 are no, why does Peukert's law belong in a discussion of 2-12V bats verses 2-6V bats? It doesn't Chuck 02 Beaver 505hp C12 Cat Trailblazer toad Posted By: livingstonsn on 02/10/08 12:23pm We just ordered the Sunforce 123 Watt solar charging kit with controller and hope to have it installed next weekend. In addition, we picked up two 6V golf cart batteries at Sam's. The first tryout for the new setup will be Big Bend (Chisos Basin) at the end of March. Since we really do bare-bones it when boondocking (just lights and the occasional furnace), I'm hoping that this will more than do the trick for our dry camping power needs. Posted By: frdmftr on 09/01/08 09:21pm Wow. 10 pages of incredible information, all about a couple of batteries. Being a 'motorhome' newby, I have a question that was never answered in this post. I have a converter/inverter 110/12v. (I have good 12v off the inverter and generator) I have 2 6v deep cycles in series (12v x 1). Both 6v's are in a very low state of charge (very dim lights). I don't believe the inverter is enough to charge them from this low of state (am I correct?). Can I charge them with a standard 12v charger, keeping them in series (12v)? I also have the solar 'trickler' on the AC cover too, but I'm sure it's maxed out for this. Any suggestions would be great, please keep it to the charging question. I got a headache from reading all the tech data in the previous 9 pages, though educational. Thanks in advance. Posted By: time2roll on 09/01/08 09:27pm frdmftr wrote: Wow. 10 pages of incredible information, all about a couple of batteries. Being a 'motorhome' newby, I have a question that was never answered in this post. I have a converter/inverter 110/12v. (I have good 12v off the inverter and generator) I have 2 6v deep cycles in series (12v x 1). Both 6v's are in a very low state of charge (very dim lights). I don't believe the inverter is enough to charge them from this low of state (am I correct?). Can I charge them with a standard 12v charger, keeping them in series (12v)? I also have the solar 'trickler' on the AC cover too, but I'm sure it's maxed out for this. Any suggestions would be great, please keep it to the charging question. I got a headache from reading all the tech data in the previous 9 pages, though educational. Thanks in advance. Without knowing model numbers it is hard to know if it will or will not charge a super low battery. Give it a jump start (jump cables) from a good battery and charging should start. Many chargers if they sense low voltage will assume it is not a 12 volt battery and will not begine charging. There is also a fair chance the charging section has quit working. Better to start a new thread as many may not look under all this nonsense to find your question. Posted By: Tankerhank on 09/02/08 08:32am frdmftr wrote: Wow. 10 pages of incredible information, all about a couple of batteries. Being a 'motorhome' newby, I have a question that was never answered in this post. I have a converter/inverter 110/12v. (I have good 12v off the inverter and generator) I have 2 6v deep cycles in series (12v x 1). Both 6v's are in a very low state of charge (very dim lights). I don't believe the inverter is enough to charge them from this low of state (am I correct?). Can I charge them with a standard 12v charger, keeping them in series (12v)? I also have the solar 'trickler' on the AC cover too, but I'm sure it's maxed out for this. Any suggestions would be great, please keep it to the charging question. I got a headache from reading all the tech data in the previous 9 pages, though educational. Thanks in advance. Yes you should be able to usethe 12V charger on the 2 6V as you discribed. I have 4 6V setup as you discribed and charnge them with 12V system. Are 2 6 volt batteries better than 2 12 volt batteries?Are Two 6-Volt Batteries Better Than Two 12-Volt Battery? There is no right or wrong answer to this question, it's all about how many amp-hours the batteries have. RVers like 6V batteries because you can get higher amperage batteries.
Do 2 6V batteries make 12V?To produce a 12 volt output, two 6 volt deep cycle batteries must be wired in series (positive to negative). Each 6 volt battery pair operates as a single 12 volt battery. You can then connect each 6 volt pair in parallel with another pair to create a larger 12 volt battery bank.
Can you have 2 6 volt batteries in series?To wire two 6-volt batteries in series to produce 12-volts, you would connect the load to the positive terminal of battery # 1. Connect the negative terminal of battery # 1 to the positive terminal of battery # 2. Ground the negative terminal of battery # 2.
Are 2 batteries better than 1?Do batteries last longer in series or parallel? Batteries last longer in parallel, because the voltage remains the same, but the amps increase. If you connect two 12v 50ah batteries in parallel, it will still be a 12 volt system, but the amps will double to 100ah, so the batteries will last longer.
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2 6 volt batteries in series vs 1 12 volt
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