[CBCS]

How should I charge my 12v 120Ah Battery?

The charger I have is a 12v 15 amp.

It has 2 options 3a or 15a? Which should I use and why?

[jeff1]

Trickle charge over night at 3amp

Stick it on 15amp and its called a booster charge and booster charges can damage a battery

[Ian Lancaster]

I bought a 'smart' battery charger.  It has four options: 2amp 8amp 12amp and 16amp.

According to the instructions you should only use the 16amp setting on batteries with a capacity in excess of 100ah.

In other words, it should be OK to charge yours at 15amps - but don't take my word for it :

[CBCS]

I've been told to charge it on 15a all the time! Thats from the battery shop where I bought it.

[charlie2]

i have a smart charge just put it on and it chooses how much charge it needs cost me65 quid .god it hurt but you can leave it on as long as you like without damaging the battery.

[windowswashed]

I bought a 'smart' battery charger.  It has four options: 2amp 8amp 12amp and 16amp.

According to the instructions you should only use the 16amp setting on batteries with a capacity in excess of 100ah.

In other words, it should be OK to charge yours at 15amps - but don't take my word for it :

Ian, is it a 'ring' charger by any chance? Very good battery charger (16amp) model.