bigalanp avatar image
bigalanp asked

MultiPlus Inverter/Charger 12v 800 VA, connecting 3 batteries

I have recently purchased a MultiPlus Inverter/Charger 12v 800 VA and I am looking to connect it up.

I have a Sealine S34 boat.

I never thought about it at the time of purchase as I was just thinking that it had a main bank of batteries that is used for the starboard engine starter and the domestics and another battery that is used for starting the port engine. But I now realise that there is also another battery that is remote and is used for the box thruster.

It looks like the MultiPlus Inverter/Charger is designed to only be connected to two banks of batteries, how do I connect the bow thruster battery so that it is charged?

The battery charger I am replacing is a Cristec CPS3 12V/25A that can supply three batteries.

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1 Answer
geomz avatar image
geomz answered ·

Actually, as far as I know, and based on the units I've used (Multi 3K) it's designed to manage *one* battery bank. And it's designed to do so against deep-discharge "house" type batteries. Not starting batteries.

It *can* also trickle charge an additional "start" (for your generator or engine, etc) battery. But it does not manage anything about it beyond a constant trickle charge.

If you wanted to use that charger (for some reason) instead of your existing separate charger, then you can get a battery isolator that will take the 1 trickle charge feed, and split it into 2. The reason the splitter is there is simply to keep one battery from back-feeding another. But at the meager 4A charge rate of that line, you're not going to get much performance from that.

If, however, you've collapsed all your (dissimilar capacity/function/load/etc) batteries, in parallel, together, and fed them all off of the main terminals on the inverter, that is a very bad idea and I would advise against doing that -for multiple reasons :)

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