"Karl Townsend" wrote: Well, now you know why that battery is dead as a
door nail. You got to have
about 40 volts to charge a 36 volt battery.
^^^^^^^^^^^^^^^^^^^^^^
Be careful interpreting voltage readings from a battery charger. It's
rectified AC (half-wave or full-wave) and the peaks will be higher than the
average or RMS value. You can get charging from a setup which, according to
the meter, shouldn't work. I'm not saying that's what your problem is, but
it is something to be aware of.

If you put a husky transformer on the input you might be able to boost the
output voltage enough to charge your battery fully. This could either be a
transformer with a 1.25 (or so) turns ratio, or one that gives you about 6
or 8 volts output, hooked series adding to the line voltage. I expect there
will be enough safety factor built into the charger to tolerate this much
over voltage.

Be aware also that if this battery has been in a discharged state for some
time, it probably has lost part of its capacity.