How to charge a 6v battery?

I have 2 12V smart chargers and a 50 year old 6amp dumb charger that has a 6v/12v switch. Is it safe to use this old charger on  a ke100 6 v battery?

Yes on the 6 volt charger but 6 amps is a bit much for a small battery just don’t leave it on very long.

Here is some info on making and using a DIY charger. I can say it works well and will charge just about any voltage battery.

www.alpharubicon.com/elect/3dollarbattggn.htm

You can get a voltage regulator for about $30.

www.amazon.com/DROK-Converter-Adjustable...0BQBXMH67?th=1&psc=1


Hook it up to your 6 volt or 12 charger.
You can control the voltage down to about 0.5v dc.
Plus you contol the current.

I just hooked my regulator up to a laptop charger to charge my 12v battery.

Battery University has a lot of info on charging batteries.

batteryuniversity.com/article/bu-405-cha...-with-a-power-supply