Help me make a A123 battery pack...

[basslover911]

I think its around 50 amps.

OH gosh so if I get a 50AH battery that means I can only run the car for one hour? (alternatorless?)... wow that seems very low. How do people go alternatorless if they can only drive the car one hour?!

[Christ]

Actually, you should only discharge them to no more than 75 percent...so with a 100ah pack, drawing 50a constant, you'll only get 1.5h usage... less when you consider losses.

Something tells me that 50a isn't normal usage for your car, though.

[Joenavy85]

something you need to consider as far as current is how much the batteries can handle, yeah your battery might have 50 Ah capacity but what is the maximum discharge rate? if your homemade pack can only handle a constant 20A draw and you try to draw 30A for an extended amount of time you can fry the pack

[basslover911]

Originally Posted by Joenavy85

something you need to consider as far as current is how much the batteries can handle, yeah your battery might have 50 Ah capacity but what is the maximum discharge rate? if your homemade pack can only handle a constant 20A draw and you try to draw 30A for an extended amount of time you can fry the pack

Well those A123's have a 70amp con and 100amp discharge capacity so I doubt ill ever even come close to it... I think.

[Joenavy85]

you have to consider how much current your starter draws on a "cold" start, obviously it won't be as bad for you as it would be for me up here in Northern Illinois

[Joenavy85]

just some info for you

Ford Focus - hard starting

i don't know what engine your zx3 has, but this could be roughly the same

[basslover911]

Originally Posted by Joenavy85

just some info for you

Ford Focus - hard starting

i don't know what engine your zx3 has, but this could be roughly the same

Na thats the diesel model, but it could be the same? Plus I want to integrate auto start/stop and Im going to be replacing the starter anyway since I don't want it to die with so much constant use.

[basslover911]

Originally Posted by Joenavy85

you have to consider how much current your starter draws on a "cold" start, obviously it won't be as bad for you as it would be for me up here in Northern Illinois

I didn't even think about that lol. Good point!

For these batteries, couldn't i just wire them in series/parallel and directly to the +/- cables? Or would i need some sort of charge controller/voltage regulator or, well, anything else?

[Joenavy85]

i'm not sure what you would need exactly for charging the battery, if you plan to use a solar panel you can get a solar charge controller online for pretty cheap. as far as series/parallel you could do that to reduce the current draw on individual cells, but i'm not sure how you would calculate that. as far as that link i posted, i know that starter would draw more than you car (most likely) but if you build your pack to handle that much it would work just fine for your car (assuming the draw is less)