How many volts is 91 heritage softail battery and how many amps is needed to charge it?

The battery in a '91 Softail is a 12 volt battery. How many amps is needed to charge it? You can charge the battery with a 1 amp trickle charger or a 10 automotive style charge. I'd recommend the 1 amp trickle charger. Leave it on charge overnight and the battery should be fully charged in the morning if it's any good. I use a "battery tender" or a "smart charger" to charge my batteries and then to keep them fully charged at all times when I'm not riding the bike. It's rated output is 1.5 amps per hour.

Good Luck
Steve

The battery is 12 volts and to charge use a 2-10 amp charger.