Yesterday, I picked up a few A123 20Ah lithium cells while I was at
Drive Green Expo in Madison, WI. I have been wanting to tinker around with these batteries for a while now.
For those who don't know, these cells are very impressive. These are the batteries that are being used in the Fisker Karma. They can handle 10C (200A) continuous discharge and up to 22C (450A) burst discharge (depends on SOC). Most other prysmatic lithium cells can only handle 3-4C continuous discharge and around 10C burst discharge. The mottcell lithium cells I have in my Prius' plugin kit which you'll see below are 40Ah batteries and only capable of I believe 2C continuous discharge. Through my testing with them I don't even really know if I would say they can do that. Even at 1/2C continuous charge/discharge they get pretty warm.
These cells weigh in at just under 1.1lbs. My Mottcell cells are roughly 3.5lbs. However, I will need to add provisions for assembling and mounting the A123 cells so it will increase their weight, but I shall revisit that when I get there.
A123 amp20 data sheet
So, here are a few images I took so you can get an idea of the size.
Here is the packaging they come in. I got four cells (enough to make a 12V battery).
I didn't have a soda can handy so I used a soup can for scale.
They're very thin!
Length.
Width.
Thickness.
This is the 20Ah A123 cell compared to my 39Ah Mottcell prysmatic cell.
I also measured the tabs. They are 1.775" wide x 1" tall. The positive terminal is aluminum and is .010" thick. The negative is plated copper and is .007" thick.
So, I have a 12V 20Ah A123 battery essentially. I'll be messing around with it a bit, developing a connecting method. Eventually I think I'll probably put it into the Paseo as the starting battery. It should weigh about 5lbs vs the current group 24 lead acid battery that is in there. While I won't be able to use it as an alternator delete battery (not enough capacity, but the wife hasn't been plugging it in anyways, and she has been driving it for the past year), it will lighten things up a bit. Funny too, the A123 cells really didn't cost a ton more than the lead acid deep cycle. If I wanted the same usable capacity I'd need 8 more lithium cells which would make it cost quite a bit more.