(ET) Report: BB600 NiCD battery performance in my Elec-Trak

[Christopher Zach <cz alembic crystel com>]

With the fall and winter coming on I thought I would share the results 
of running BB600 NiCD batteries in the E20.

Currently I have two strings of 30 NiCD cells in my E20. They all fit in 
the rear battery box with a set of 15, then a 2*4 vertical spacer, then 
a set of 15, then a 2*4 spacer and the other 30 batteries mounted the 
same way. The result is 4 quadrants of 15 cells. This gives me a nominal 
voltage of 36 volts, with a capacity of 60ah for the pack.

I could put another 30 cells in the front, but right now I just have a 
pair of dead 80AH AGM batteries up there for ballast.

Overall performance is *excellent*. Using a Link 10, I have noticed that 
I can pull a good 26ah per string without problems. This is in the 
summer, winter, mowing, tilling, snowblowing. The batteries are totally 
unaffected by the cold. In winter I put an extra 30 cells in the rear 
weight box and run with three strings. With that I can do just about 
anything with the snowblower. I have been able to pull over 150 amps per 
string peak without the batteries sagging too much.

The E20 charger for whatever reason charges these cells perfectly. I 
think it's the 45 volt end charge coupled with the high current charge 
up to the taper voltage (around 44 volts or so) that makes them happy.

I typically have to water them once a year, the biggest problem is 
washing the dust off the tops before opening the caps. Takes about 15-30 
minutes to do.

The biggest problem is that they weigh less than the T105's so there is 
less weight in the tractor. This doesn't seem to be a big issue for the 
back batteries, but I'm wondering if the front would be heavy enough to 
maintain steering traction if I put another 30 up there. Maybe I need a 
lead weight under the front or something like that; anyone know if one 
can have a weight cast in the shape of the front battery box base? On 
the other hand it would be easier on the steering. Hm.

Given reasonable care, I expect this pack to last about 50-100 years or so.

Part of the reason I'm writing this is because I am thinking of removing 
the 250 cells that are in my S10 pickup truck. I put them in there 
looking for a 30 mile range truck, however trying to charge 250 of them 
in series is a lot more complex than 30 of them. So if anyone would like 
to try these cells, please let me know. I probably won't swap them out 
before the spring, and 250 cells would be enough to do about 3 tractors.

Chris