Battery charging question

[NanciL]

Can a Marine "No Maintenance" battery be charged ?

I just bought a small pop up and we won't be using it till October.
the battery is a Marine sealed "no maintenance one".

I decided to keep it in my shop and once a month put it on my charger.
This morning I tried it for the first time and after I made the connections I got a loud pop and smoke came from the charger. Naturally I immediately unplug and disconnected everything.

On my charger I can chose "wet", "AGM" or "Gel.
I have always used "wet" so that is what I chose.

Thinking I fried the charger, I tried it on a small 12 volt battery from my ATV and to my surprise it worked fine.

I check the Marine battery and I am getting 11.5 volts on my meter

Can any one explain why I would have gotten what appeared to be some sort of short ?

Jack L

[Fubeca]

Of course a marine battery can be charged. The two most likely scenarios are 1) the charger cables were inadvertently reversed, 2) the battery is junk and was discharged/recharged backwards resulting in a reversed polarity.

Stick a digital meter on it - is it 11.5v or -11.5v?

[RPreeb]

I can't answer the OP's question, but when I put my battery in winter storage, I put it on a battery tender, not a charger. Seems to be better on the battery using a smart tender, even if the charger has a trickle mode.

[beemerphile1]

Did you connect the battery backward?