Archive for June, 2009

Battery decision time

Monday, June 8th, 2009

I went and did some initial testing on the 12 volt system in the car, and it doesn’t have any obvious shorts, so it is ready for testing.

However.  A number of disturbing reports on how badly the car will perform with 1200 pounds of lead acid battery has me very worried.  I’ve read several real-world scenarios of max 50 miles and very weak acceleration.  Since I need need to have freeway speed and the ability to climb some steep hills, this is just not acceptable.

The only solution is to go for a higher voltage battery pack, and lead acid batteries won’t do it.

Time for Lithium.  Lithium Iron Phosphate.  Trouble is, that these are only made in China right now.  And they are expensive.

Comparison time (shipping not included):

  • Lead acid pack, 144 volt, 12.9 kw, $2600.
  • Lithium pack, 163 volt, 13.7 kw, $8000.
  • Lithium pack, 243 volt, 20.4 kw, $12,000.

That last pack will take up the same space as the lead acid batteries, but provide much more voltage and almost twice the available capacity.  The cost is just astounding though.

I’ll keep you posted on any further thoughts on this.