Battery Choice

[Jeremy Bloyd-Peshkin]

Hey guys. I'm waffling on a decision. I can either buy lead acid batteries and have some leftover budget, or I can spend every last dollar and build a LiFePO4 pack. What should I do?

[Jeff Kantarek]

What's the watt-hour difference?

Jeff Kantarek
P: 708.921.0248

On Jan 16, 2013 7:53 PM, "Jeremy Bloyd-Peshkin" <jbloyd...@gmail.com> wrote:

Hey guys. I'm waffling on a decision. I can either buy lead acid batteries and have some leftover budget, or I can spend every last dollar and build a LiFePO4 pack. What should I do?

--

[Jeremy Bloyd-Peshkin]

They are both 25.4v, so what's really important is the amp-hour difference. The lead acids would be 7ah, or theoretically 18ah if I use the batteries around the space (although at a massive weight penalty). The lithium packs would either be 4.4ah or 6.6ah, but with much higher current discharge and a flatter discharge curve.

So.
Lead acid: cheap, high capacity, heavy, low discharge.
Lithium: expensive, low capacity, light, high discharge, very fast charging.

That's why I can't decide.

--
 
 

[Jeff Kantarek]

If we're going to be able to use them for more than one season I say go for it.

Jeff Kantarek
P: 708.921.0248

--
 
 

[Josh Krueger]

Also keep in mind the cost it would take to have spare battery packs in the pit.

Whats the recharge time on the lithiums?

[Jeremy Bloyd-Peshkin]

15 mins.

Sent from my tiny handheld device.

--
 
 

[Jeff Kantarek]

At that rate you'd almost be able to get away with sharing batteries between cars

Jeff Kantarek
P: 708.921.0248

--
 
 

[Jeremy Bloyd-Peshkin]

It depends on how long each car lasts on a pack.