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Loss of domestic electric

We have suddenly lost 12v and 240v power. Inverter alarm light flashing and 12v fridge light too. Lights dim. Control panel meter shows charging at about 14v. Batteries topped up Ok, no loose wires on alternator. Any thoughts on what problem is?

Asked by: Paul Taylor  | 10.52am, Thursday 2 July

WW says:

It sounds very much as though one or more of your domestic batteries has failed. Although your control panel shows a charge voltage of 14V, I suspect that if you measure the voltage when the engine is not running that the overall voltage will drop quite quickly.
Assuming that your boat has several 12V batteries connected in parallel; one or more of the batteries has lost a cell which will drag the whole lot down. The (temporary) solution is to separate all the batteries electrically by disconnecting one connection on each battery, and to measure the voltage of each individual battery. Reconnect the ones that show around 12V, leaving the others disconnected. This will give you a working battery bank of less capacity as a temporary fix. The long term solution is to replace ALL the batteries as the others are probably likely to fail soon.
To ensure a parallel connected battery bank is reliable, all the batteries need to be the same type and ideally from the same manufacturing batch.

Rupert Smedley  | 12.01PM, Thursday 2 July

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