The other day, I was able to get a used 72V charger in unknown condition, but the cost was right (free!)
This charger has both a 12V and a 72V output on it.
I wired up a power cord for it and tested the outputs. The 12V out was sending about 13.5 volts, but the 72V output wasn't doing anything.
I have been told that many higher voltage chargers don't do anything unless they are hooked up to the batteries, so it was time to rig some up.
I pulled out my "second-string" of batteries and lined them up in the garage. I dug my pile of forklift cables out of the snow and found some with terminals on both ends.
I strung the batteries in series with the forlift cables and then hooked up the charger.
Measuring the string of voltage, the multimeter read 75.4V, which comes to a little more than 12.5V each, which isn't bad considering that the batteries are just sitting in my garage, and it's still cold out. (1℉ right now)
When I turned the charger on, the Killawatt measuring it only went up to about 20 watts. I'm sure that's just the power used to run the two fans on the charger.
I heard a few clicks once or twice from inside the charger. Something's not quite right with it.
Maybe at the next EV Build Day, I can have some of the other guys take a look at it.
If nothing else, it's a free 12V charger.