highest ah 12V battery - DIY Electric Car Forums
Go Back  

DIY Electric Car Forums > EV Conversions and Builds > Batteries and Charging

Register Blogs FAQ Members List Social Groups Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 10-04-2008, 10:58 PM
chamilun chamilun is offline
Senior Member
 
Join Date: Jun 2008
Posts: 179
chamilun is on a distinguished road
Default highest ah 12V battery

what is the highest ah 12V battery available? when I say available, meaning a battery that costs circa $200 and can be found without driving to canada.

Im leaning towards a us battery or trojan 12Volt, but still think there is a better battery out there.

thanks
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 10-04-2008, 11:45 PM
gmijackso gmijackso is offline
Member
 
Join Date: Sep 2008
Location: Las Vegas, NV
Posts: 98
gmijackso is on a distinguished road
Default Re: highest ah 12V battery

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.

Last edited by gmijackso; 10-07-2008 at 12:48 AM. Reason: Added batteries
Reply With Quote
  #3  
Old 10-05-2008, 09:07 AM
chamilun chamilun is offline
Senior Member
 
Join Date: Jun 2008
Posts: 179
chamilun is on a distinguished road
Default Re: highest ah 12V battery

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
Reply With Quote
  #4  
Old 10-05-2008, 12:07 PM
TX_Dj's Avatar
TX_Dj TX_Dj is offline
SPAM Cop
 
Join Date: Jul 2008
Location: Texas, Plano (Dallas)
Posts: 1,499
TX_Dj is on a distinguished road
Default Re: highest ah 12V battery

"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.
__________________
cheers,
dj
"I'm No Expert!(TM)"
A fuel and his money are soon parted...
Reply With Quote
  #5  
Old 10-05-2008, 01:36 PM
chamilun chamilun is offline
Senior Member
 
Join Date: Jun 2008
Posts: 179
chamilun is on a distinguished road
Default Re: highest ah 12V battery

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.
Reply With Quote
  #6  
Old 10-05-2008, 01:59 PM
gmijackso gmijackso is offline
Member
 
Join Date: Sep 2008
Location: Las Vegas, NV
Posts: 98
gmijackso is on a distinguished road
Default Re: highest ah 12V battery

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.
Reply With Quote
  #7  
Old 10-05-2008, 02:29 PM
TX_Dj's Avatar
TX_Dj TX_Dj is offline
SPAM Cop
 
Join Date: Jul 2008
Location: Texas, Plano (Dallas)
Posts: 1,499
TX_Dj is on a distinguished road
Default Re: highest ah 12V battery

Quote:
Originally Posted by chamilun View Post
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.

Quote:
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.
__________________
cheers,
dj
"I'm No Expert!(TM)"
A fuel and his money are soon parted...
Reply With Quote
  #8  
Old 10-05-2008, 02:57 PM
gmijackso gmijackso is offline
Member
 
Join Date: Sep 2008
Location: Las Vegas, NV
Posts: 98
gmijackso is on a distinguished road
Default Re: highest ah 12V battery

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.
Reply With Quote
  #9  
Old 10-05-2008, 03:22 PM
chamilun chamilun is offline
Senior Member
 
Join Date: Jun 2008
Posts: 179
chamilun is on a distinguished road
Default Re: highest ah 12V battery

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.
Reply With Quote
  #10  
Old 10-05-2008, 03:49 PM
TX_Dj's Avatar
TX_Dj TX_Dj is offline
SPAM Cop
 
Join Date: Jul 2008
Location: Texas, Plano (Dallas)
Posts: 1,499
TX_Dj is on a distinguished road
Default Re: highest ah 12V battery

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.
__________________
cheers,
dj
"I'm No Expert!(TM)"
A fuel and his money are soon parted...
Reply With Quote
Reply

Share or Bookmark this

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

 
Support DIY Electric Car
Sponsors

All times are GMT -6. The time now is 12:01 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Ad Management by RedTyger