We have a 275 with twin batteries and the factory-fitted electrics (we believe). When the engine is running and charging the batteries is this charging both batteries or does it depend on the setting of the isolator switch? How can one tell?
Any help appreciated.

David

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Hi David
In the factory std set up battery switch needs to be turned on for charging ie turn on to 1 or 2 start engine then switch to 1+2 to charge both or 1 or 2 to charge them individually. To confirm charging use a meter directly on the batteries, whilst being charged they should be about 14.5V or even higher. When charged but rested they should be about 12.5V. There is a lot of literature on charging marine batteries, written by more experienced people than me , check on it more more precise figures. Note as a rule of thumb do not run the engine with the battery switch turned to 0 as in this case the alternator could be open circuit which would allow the voltage to rise sufficiently to blow up the bridge rectifier.

Jan
325/32 ex 275