(ET) Thoughts on NiCDs and card 4

[Christopher Zach <czach computer org>]

Got about 60ah from the NiCD pack today; very busy one doing mowing, 
sweeping, and driving all day long. Finally one side of the pack started 
dropping out, so now it's all on charge again.

I think I'm going to want to put in a pair of contactors on the packs so 
they are not connected when the tractor is off, and can allow me to 
isolate the tractor to run/charge on one pack or the other. Anyone know 
if the start switch can be tapped to power a seperate pair of 
contactors, or should I put in another relay for this? Or does kicking 
start alone latch any of the relays?

Card 4 is also interesting; I fixed that burned connection on it, popped 
it back in the tractor, and promptly set one of the diodes on fire. Hm. 
Guess it was a blown diode after all. I gave up and pulled all four of 
those field diodes, drilled out the holes a bit wider, and installed 
four new Radio Shack 3 amp diodes. 400 volt PIV as well; figured with 
the field dropping out you might get some surges. This should fix the 
problem, however I think given this and other people with problems it's 
time to replace your diodes. Drill out the holes with a tiny drill bit, 
and install the RS 3 amp ones. My guess is they used 1 amp diodes, and 
aside from being old, they're just too small.

Another thought: The control bus is fused by a 20 amp fuse. That's way 
too high for some of those components, maybe we should use a 5 or 10 amp 
fuse?

Chris