Help needed - battery charger

[peterandjeanette]

Scene setting -

Boat has 4 x 12 volt batteries, all two years old. One for port engine, one for starboard engine and two for domestic. Charge comes from factory fitted 240 volt charger when on shore power and engines when moving around.

Problem -

When the 240 volt charger is switched on it shows maximum charge - as confirmed by the ampmeter on the main panel - 60 amps. After about 10 minutes at 60 amps the 80 amp circuit breaker - marked "battery cahrger" on the HEAVY DUTY DISTRUBUTION BOX trips out.
Now, either the charger is not sensing the charge in the battery or one or more batteries are completely knackered.

I also notice that when moving around - ie on engine charging, the "charge ampmeter" shows no sign of life.

What do you think? So far, there has been no problem with starting either engine, and the domestic voltmeter shows a reading of 12.5 volts.

All help gratefully received.

 

[halcyon]

What make and type of mains charger?

Brian

 

[peterandjeanette]

Mains charger is Mastervolt MAAS 12/60. Given excellent service - so far!

 

[AndrewB]

It might just be the circuit breaker. A few of our oldest ones (up to 20 years old) have started to pop somewhat below their rating, and have had to be replaced.

 

[LadyInBed]

I take it that the mains charger is trying to charge all 4 batteries (in parallel) at the same time.
I would isolate some (2 or 3) of the batteries and see what happens when only charging 1 or 2 batteries.
If it charges 2 ok, try it on the other 2.
If that's all ok then it is probably the circuit breaker that can't handle the current to 4 batteries not the batteries.
If it trips on all the batteries when only charging 1 battery at a time then it's the circuit breaker.
If it trips on any of the batteries on their own but ok on the other batteries then that battery is knackered.