Is it the onboard charger or bad battery

[garry]

I have a Minn Kota MK210 onboard charger hooked up to two batteries for my 24 volt trolling motor, worked perfectly last season. Topped off the batteries this spring and plugged in the charger, had boat out twice and everything seemed fine, went out again yesterday and trolling motor had no power, when I got home I plugged in the charger to check if it was working. Today I took off the caps to the batteries to check the charge level and one was perfect and the other was smoking with no water in the battery. I filled the battery with water to check what would happen, the water is bubbling, do you think the battery is bad or that the charger got stuck in the charging mode to boil out the water when it should have went to the maintance charge. How do I find out if the issue is the charger or the battery?

 

[boat1010]

Re: Is it the onboard charger or bad battery

Are you charging both batteries together? If you are then I doubt if it is the charger. If you filled both batteries before you started charging them then I would say you have a bad battery. You can check the batteries with a hydrometer to see if one is bad.

 

[garry]

Re: Is it the onboard charger or bad battery

Boat1010, thanks for the quick reply,

It is a 2 bank charger so both batteries are charging, both batteries tested good before topping them off and hooking up to the charger, been plugged in to the charger for about 2 weeks. I leave it hooked up because once the batteries are charged it is supposed to maintain the charged level, worked perfectly last season.

 

[ebry710]

Re: Is it the onboard charger or bad battery

Boat1010, thanks for the quick reply,

It is a 2 bank charger so both batteries are charging, both batteries tested good before topping them off and hooking up to the charger, been plugged in to the charger for about 2 weeks. I leave it hooked up because once the batteries are charged it is supposed to maintain the charged level, worked perfectly last season.

If both batteries have tested good, then you've answered the question. Sounds like a charger problem.