When I put the charger on the battery, it didn't seem to want to take a charge. I have no idea how old the battery is.

It's almost an academic question at this point. Once I'm done doing some brake work on my F*ord Galaxie, I'm going to focus on the 3100, the first task being to convert it to 12V. I want to run a radio, so 12V is a must as far as I'm concerned.

Thanks...

Chris