Most old tractors use 6 volt batteries. It is common practice to stick 8
volt batteries in them to give them a little more zap. No changes are
necessary - their systems can handle it.

My problem is how to charge an 8 volt battery when it has been sitting for a
while and has been worn down. I have three battery chargers - a 12V
10-30-50 amp, a 12V 2 or 10 amp, and a 6 or 12 volt 4 amp.

I went to a local battery plave and the guy told me to use 12 volt low
amperage. Thoughts ?