# highest ah 12V battery



## gmijackso (Sep 30, 2008)

I know this doesn't so much fall into the highest category you're looking for, but I was just doing some battery searching today around town and figured I'd throw in what I found today.

Local Sams club:
Energizer 27DC (deep cycle marine) 12V, 115 AH, 12 Mo. Free replace, 36 Mo. Prorate, $66.87
Energizer 29HM (deep cycle marine) 12V, 125 AH, 12 Mo. Free replace, 36 Mo. Prorate, $76.68
Optima 34DC (Marine Deep Cycle) 12V, missed notes on this one, $155.82

Energizer GC8 (Golf Cart) 8V, 105 AH, 12 Mo. Free replace, 0 Mo Prorate, $77.82
Energizer GC2 (Golf Cart) 6V, 220 AH, 12 Mo. Free replace, 0 Mo Prorate, $71.28

Local Autozone:
Duralast 24MD-DL? (Marine Deep cycle) 12V, 85 AH, $69.99

*Added 10-6-2008
*
Local WalMart:
Everstart MAXX-29 Deep Cycle, 12V, 125 AH, 18 Mo. Free replace, $76.88
Everstart 24DC-4 Deep Cycle, 12V 75 AH, ???, $56.88
Everstart 27DC-6 Deep Cycle, 12V 115 AH, 61.88


I'll try to post more here as I get them. I too am kinda looking for the highest AH 12V for a reasonable price, but maybe pairing 6V is the best bet so I'm just accumulating data. Hope this helps at least a little.


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## chamilun (Jun 17, 2008)

awesome information!

ill add the us battery 12V XC has 20hr rating of 155

a us battery 185 hc xc 20hr rating of 220. 

185e xc 185 ah @ 20 hr

their 8volt 8vgchc is 183 ah

the trojan t-1275 is 150 ah weight 85lbs i believe

the 31-gel trojan is 102


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## TX_Dj (Jul 25, 2008)

"Biggest Ah" is nice, but try to understand what the Peukert's exponent is for each of those batteries. That's the real determining factor.

20-hour rates sound real nice, but are useless as a determining factor for runtime in an EV.

You need to be looking at the 1-hour or faster rates, and most companies aren't going to show you that.

"Marine Deep Cycle" is the next best thing to a starter battery, but a far cry from a true deep cycle traction battery.

"Only the rich can afford cheap batteries." (Meaning, if you get 100 cycles out of a $50 battery, vs a $150 battery that gets 500 cycles.)

If you make a comparison on US Battery's site, you'll see that not all are equal. 

You'll see the US185HC is the "biggest" capacity at the 1-hour rate, which is 118 Ah. Consider of course, that this is sold as a "215 Ah" battery, and you'll find yourself disappointed when you run it at the 1-hour rate or faster.

Similarly, the US250HC (275 Ah 20-hour) and the US305 (305 Ah 20-hour) are only 5 Ah difference from each other at the 1-hour rate. (172/177 respectively). Then consider how many more US250HC's you may be able to fit, vs. the larger US305.

Compare that to something like a Trojan T-1275, which is rated at 150 Ah at the 20-hour rate, but 70 Ah at the 1-hour rate.

Don't fall into the trap of comparing batteries for traction applications by the 20-hour rate. It's not a fair fight.


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## chamilun (Jun 17, 2008)

20 ah rate is a quick way to roughly compare. the 5 hr and 1 hr will obviously be less, but the amount less can be somewhat consistent. so if you know the 20 hr rate, at least you have an idea about 5 hr. i never see the 1 hr rate given.

time @ 75 amps may be the best determinant anyways.


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## gmijackso (Sep 30, 2008)

Another thing to keep in mind is cost and warranty. For instance, the golf cart batteries I priced are going to be true deep cycle, but come only with a 1 year warranty (probably because it is known exactly how hard they're intended to be used) but the marine deep cycles have an additional pro-rated warranty.

If you purchase a marine deep cycle at someplace different, say AutoZone, you may be able to get a 3 year free replacement warranty for not much price difference when compared to other batteries. While the battery itself may not be perfect for EV use, if you can afford the need to exchange them from time to time when they fail, it might actually be better for you to go with a cheaper battery and get a warranty replacement every few hundred cycles (each year or so). If you live in a very hot or very cold climate, the battery place may already expect replacements each year or so, I know they do here. One summer of 120+ ambient air temps is about all most batteries can handle.


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## TX_Dj (Jul 25, 2008)

chamilun said:


> 20 ah rate is a quick way to roughly compare. the 5 hr and 1 hr will obviously be less, but the amount less can be somewhat consistent. so if you know the 20 hr rate, at least you have an idea about 5 hr. i never see the 1 hr rate given.


US Battery gives the 1-hour rate, you just have to look for the sheet in their PDF section. My point is more to the fact that if you look at battery X and battery Y, of the same Ah capacity, their Peukert's exponent can be different, leading to a reduced capacity at a higher rate, even though they appear similar at the 20-hour rate.



> time @ 75 amps may be the best determinant anyways.


There's been a lot of debate about this, as many mfrs seem to choose whatever amperage makes their battery look good, and also because an EV application still isn't a steady draw. I.E. if you can cruise at 75 amps, that's great, but you might pull 200 getting up to the cruise speed. That brief time at the higher amperage will affect the "reserve minutes capacity" at the lower amperage.

For example, the US185HC shows 1313 minutes at 10A (~20-hour Ah rate), but shows 110 minutes at 75A, 74 minutes at 100A, and 56 minutes at 125A. Compare that to the non-HC version of the same battery, and the respective numbers shown above are 1093, 100, 71 and 54. At low rates there's a HUGE difference (3.6 more hours at 10A for the HC) but at high rates there's no significant difference. However, at the 20-hour Ah rate, these are 215 (HC) and 195 (non-HC) and at the 1-hour Ah rate, these are 118 (HC) and 101 (non-HC).

Another example, also using US Battery products (since they have a great pair of charts comparing most of their batteries), and looking at 6v batteries, we find this: The US250HC and US305 (non-HC) are 275 (250HC) and 305 (305) at 20-hours, and 172/177 respectively at the 1-hour rate, as I mentioned before. But if we look at the reserve capacity chart and compare these two, the 305 is 1850 minutes at 10A and the 250HC is 1736 minutes at 10A. Now comparing the same rates as the paragraph above, the 305 is 165 min @ 75A, 115 min @ 100A, and 87 min @ 125A. The 250HC, mind you the "lesser capacity battery" at the 20-hour rate, beats the "bigger" battery in each of those, with 168 min @ 75A, 120 min @ 100A, and 92 min @ 125A.

The sad thing is, there is no easy "Apples to Apples" comparison of one battery to another, as each battery's construction will give it a slightly different Peukert's exponent than another. However, in the case of the 250HC vs the 305, you will save space and weight and get comparable or better range from the lighter battery.


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## gmijackso (Sep 30, 2008)

Someplace I had seen s chart or a study where somebody did a "yearly cost analysis" of several different solar storage deep cycle batteries. In this analysis they took into account the original cost of the batteries, the AH ratings (as they kept their pack voltage and capacity consistent), the warranty length and the average time between failures. Maybe everybody here needs to work together to try to get the same type of data collected.

Those are pretty much the same considerations EV users need to take into account with the added problem of weight. If we could come up with a "standard average pack" or maybe a "low voltage standard" and a "high voltage standard". We could scale each battery for that pack and use real users data to come up with a total cost over say 10 or 15 years. Once that is completed, everybody could scale that data to the size of the pack they wish to create and figure out what is going to work best for them.

Think it's possible? If there are enough people on board, I'll start a new thread to start collecting the data. Would basically need a consensus on some average pack sizes, makes and models of batteries people are using, their real world run times at x current (AH ratings for EV), and failure rates. Everything else should be able to be found online such as price and warranty. Then it's just a spreadsheet away from being usable.


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## chamilun (Jun 17, 2008)

good discussion.

i think the website youre referring to determined the AGM was the way to go (solar speaking). the way evs need surges of demand rules these out, i believe.

im going to go through some completed conversions and see what people think.


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## TX_Dj (Jul 25, 2008)

AGM is a good fit for some EVs. The Corbin Sparrow/NGV comes to mind, as does the Commuter Cars Tango.

Typically any place that is tight, light, and needs good power delivery, AGM fits well. AGMs typically don't have as much capacity though- but with something very aero and very light, the capacity is less of a determining factor.


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## gmijackso (Sep 30, 2008)

Added batteries at my local Wal-Mart today in Post #2. 

WalMart also had a book of Everstart batteries that I didn't get a chance to look at. The guy behind the counter was already over hours he said and had to punch out. He then came back and helped me find the price for the 27DC-6. He then tried to tell me that Deep Cycle batteries required a regular starting battery as well, becasue the starting battery started the deep cycle... I tried to correct him and explain the difference and the uses of the two batteries, and he responded with "just telling you what people tell me" and walked away. I decided I'd come back later and check the book. I know it's a gamble, but I find it hard to believe that I'd come back when somebody less knowledgeable was manning the station.


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## TX_Dj (Jul 25, 2008)

gmijackso said:


> I'd come back when somebody less knowledgeable was manning the station.


Pep Boys / Wal Mart / Target / etc...

I would never trust any of those types of organizations to know the first thing about a car, let alone anything authoritative about battery technologies.

Your chance of finding comparable or less competency behind the counter are good.


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## chamilun (Jun 17, 2008)

the batteries at sams, wm, and many other local places are rebadged johnson controls. i dont believe the 27 29 are true deep cycle batteries.


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## fugdabug (Jul 14, 2008)

I would have to put in a word for US Battery,.. they have a 12V Deep Cycle the US185HCXC that is rated at 220Ahr... I don't know the cost as I didn't contact our local dealer on it I just went and did a search on the website at US Battery. I would give them a look... and they weigh a bit LESS than the Trojans... goo luc


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## chamilun (Jun 17, 2008)

i ruled out us battery because I couldnt find a local distributor (nashville). in fact, all of the distributors listed on their website told me they no longer do business with them. i found that odd, and moved on (to Trojans)

for what its worth, Trojan has the J185 that was 2x taller than a t-1275 and has a huge ah rating down to the 5hr rating. i dont know why no one has experimented with these (maybe for a truck?). see my interstate battery post for why they may not be the right terminals.


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## Coley (Jul 26, 2007)

I have been testing 4 used MK Power GEL batteries against the MAXX29. 

Even though it has a rating of 125AH, the new MAXX29 is no match for the used GELS.

Even charging the GELs to 14.2 and then the MAXX29 to 14.30, it still can't come close to putting out amps as long as the 73.6 AH MKs.

I only run 10 miles before I recharge, so the pack isn't down much.

The MAXX29 was only good for 1100 miles or so. Then it drops off like a rock.

That seems to be the problem with any of the Marine/Deepcycles that I have tried.


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## chamilun (Jun 17, 2008)

Coley,
thanks for posting your experience with that battery. Theres information everywhere that claims its the second coming (cheap and quality). After doing extensive research, down to manufacture level (including whether JC or Exide is making), there is a reason it is cheaper. 

the golf cart distributor I spoke to said that he does recommend people buy their 6V or 8V batt @ Sams, but said they will last half as long as the Trojans.

that MK Power Gel sounds really good as well, I just needed more range


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## TheSGC (Nov 15, 2007)

Coley said:


> I have been testing 4 used MK Power GEL batteries against the MAXX29.
> 
> Even though it has a rating of 125AH, the new MAXX29 is no match for the used GELS.
> 
> ...


Coley, were your MAXX29's from Exide or Johnson Controls?


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## Zemmo (Sep 13, 2007)

gmijackso said:


> Think it's possible? If there are enough people on board, I'll start a new thread to start collecting the data. Would basically need a consensus on some average pack sizes, makes and models of batteries people are using, their real world run times at x current (AH ratings for EV), and failure rates. Everything else should be able to be found online such as price and warranty. Then it's just a spreadsheet away from being usable.


I think there might be too many variables to accurately track this type of data. People have different maintenance patterns, driving patterns, BMS equipment, knowing how to properly set their charger, etc. Just a lot of things to consider on a study like that. An example is, I have just gotten into some electronics for batteries. They seem to be bringing more life out of my battery pack (they are 2003 Trojan stock) but not every one will spend the extra money to get every last bit out of their batteries. The data would be interesting to know but I don't know how accurate it would be.


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## chamilun (Jun 17, 2008)

Zemmo,
what type of electronics? like BMS?

thanks


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## Zemmo (Sep 13, 2007)

I assume you are referring to what I am using. I built battery desulfators and charging regulators. The desulfators are helping clean the batteries of sulfation and the charging regulators are preventing batteries from getting over charged while the others are catching up. I wish I could afford some other kind of BMS but for lead acid batteries, they aren't really needed. So thats why I just built the cheaper stuff to put onto the batteries. Something is better than nothing.


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## Coley (Jul 26, 2007)

Coley, were your MAXX29's from Exide or Johnson Controls?

Exide.


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## diver653 (Sep 20, 2011)

Zemmo said:


> I assume you are referring to what I am using. I built battery desulfators and charging regulators.


Are there instructions some where for doing these desulfators and regulators?


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## lockduke (Dec 25, 2009)

Having just read these post's there is also a battery made for floor scrubbers that is 350 AH I was just going to purchase a set for a test for my solar panel before I scale up to the full scale system. they may be what you are looking for. I saw these at Tractor Supply, I believe they are made by Exide. I am not totally positive but they are on their display sheet / catalog I also have been using a DEKA AGM 908-D 285 AH battery for almost 3 years with my 3000/6000 watt inverter on my service truck to power all of my accessories like overhead florescent 12vdc lights grinders and key machines as well as 1000W halogen lights for outside the truck.Just last weekend I was working on the truck and left all the lights on while I worked on it, and did not want to try and use the alternator (130amp) to try and recharge it. So I used my Schumacher battery charger to recharge overnight and it recovered without any problems. Just my two cents. Duke.P.S. If you want to know anything else, just e-mail me and I will be glad to give any info I can.


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