August 2008


The first round of baseline testing of the cells I received from a
scooter vendor for testing, show that they can achieve their nameplate
rating of 40ah at a 1C discharge rate, down to 2.5v. They typically
put out 2-5% more than that. All testing was done with a constant
current load of 40 amps. Recharging was constant current at 10 amps to
4.25v max.

The temperature of the exterior of the cells in my garage were 103F.
Ambient estimate was about 75-80F. I’ll track the ambient more closely
next round. More testing will make clear if temperature produced is
the limiting factor in using these cells in an EV.

During discharge I noticed that the voltage fell much faster when it
hit 2.8v. So I suspect this will become more important as the loads go
up in future testing.

Next round of baseline testing will be discharging at 60 amps constant
current down to 2.5v. After that it will be time to put them in the truck.

Brazil!
– Photo album will be on my website.

Thundersky Lithium cell testing thanks to Allen at Green E Motors!!!

1.5 sets of A123 cells in house.

My trip to Brazil!