# AA batteries **URL:** \ **Category:** EV Small Talk\ **Created:** [July 22, 2008, 4:31pm UTC](https://community.electricforum.com/t/aa-batteries/841 "2008-07-22T16:31:41Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![tomusiaka](https://avatars.discourse-cdn.com/v4/letter/t/e19b73/32.png) [@tomusiaka](https://community.electricforum.com/u/tomusiaka)\ **Post date:** [July 22, 2008, 4:31pm UTC](https://community.electricforum.com/t/aa-batteries/841/1 "2008-07-22T16:31:41Z")
Hello, I have done a comparison of the big car batteries and I am not an physics expert (if I was I wouldn’t probably ask questions here) but based on my calculations, connecting a bunch of AA batteries would end up being cheaper and lighter than connecting the large betteries. Here is my comparison: [B]Car battery:[/B] Amper-hour: 40Ah Voltage: 12V Energy: 12V\*40Ah = 48Wh mass: 1.6kg Energy/mass: 30Wh/kg price: $80 To store 12kWh: batterries needed: 12000Wh/48Wh = 250 price: $80 \* 250 = [B]$20000[/B] mass: 1.6kg \* 250 = [B]400kg[/B] Therefore, to store 12kWh we need to pay $20,000 and our vehicle will weigh 400kg more. Now, if we used a bunch of AA NiMH betteries: [B]AA battery:[/B] Amper-hour: 2.5Ah Voltage: 1.2V Energy: 1.2V\*2.5Ah = 3Wh mass: 31g = 0.031kg Energy/mass: 3Wh/0.031kg = 97Wh/kg price: $1 To store 12kWh: batterries needed: 12000Wh / 3Wh = 4000 price: $1 \* 4000 = [B]$4000[/B] mass: 0.031kg \* 4000 = [B]124kg[/B] Therefore, based on my calculations (tell me if I’m wrong), by connecting 4000 AA batteries together, we would be able to store 12kWh of energy by just paying $4000 and our vehicle will weigh only 124kg more. Please let me know why AA batteries are not being used (whether I have some error in my calculations or there is some other reason for this) Thank you ---
**Author:** ![frodus](https://avatars.discourse-cdn.com/v4/letter/f/e95f7d/32.png) [@frodus](https://community.electricforum.com/u/frodus)\ **Post date:** [July 22, 2008, 5:11pm UTC](https://community.electricforum.com/t/aa-batteries/841/2 "2008-07-22T17:11:06Z")
You calculated wrong… 12\*40=480Wh… not 480, that would make your pack cost $2,000, and not 20,000. Cost for 25 batteries. Another reason we don’t use em, is because of connection loss for each welded tab. By the way, where’d you find a 1.6kg 40Ah 12V battery? ---
**Author:** ![tomusiaka](https://avatars.discourse-cdn.com/v4/letter/t/e19b73/32.png) [@tomusiaka](https://community.electricforum.com/u/tomusiaka)\ **Post date:** [July 24, 2008, 7:09am UTC](https://community.electricforum.com/t/aa-batteries/841/3 "2008-07-24T07:09:31Z")
I see my mistake. I would need 25 batteries. The weigh I provided is wrong too. A single 40Ah, 12V battery weighs 12 kg. Therefore, the total weight would be 25 \* 12kg = 300kg. Thank you for enlightening me. ---
**Author:** ![frodus](https://avatars.discourse-cdn.com/v4/letter/f/e95f7d/32.png) [@frodus](https://community.electricforum.com/u/frodus)\ **Post date:** [July 24, 2008, 8:44am UTC](https://community.electricforum.com/t/aa-batteries/841/4 "2008-07-24T08:44:04Z")
no prob, i make math mistakes a ton, and end up eating my words 🙂 there’s an electric land racer that broke electric land speed records with C batteries… lots of them, in tubes. ---
**Author:** ![tomusiaka](https://avatars.discourse-cdn.com/v4/letter/t/e19b73/32.png) [@tomusiaka](https://community.electricforum.com/u/tomusiaka)\ **Post date:** [July 24, 2008, 8:56am UTC](https://community.electricforum.com/t/aa-batteries/841/5 "2008-07-24T08:56:48Z")
Yes, that’s what I was thinking about too. If the batteries were connected in a string, you could get a pretty high voltage (1.2V \* 4000 = 4800V), which would give a nice kick I think (tell me if I’m wrong). I also just read news about an electric vehicle for 150,000 GBP that is about to come on market with 700 horsepower: [http://www.lightningcarcompany.co.uk/](http://www.lightningcarcompany.co.uk/)