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urban-caterpillar avatar image
urban-caterpillar asked

Connecting a 12/240v inverter to the AC grid terminal on multiplus IIGX

Hi all. I've been trying to come up with a way to use my diesel ute as an intermittent backup generator for my multiplus II off grid system which comprises of an MPPT, Multiplus 3000 II-GX and a powerplus 48v lithium battery bank.


I am considering the possibility of using a 12/240 pure sine wave inverter on the battery terminals of the car, and running the AC output straight into the grid terminals on the multiplus to charge the battery bank if PV power is not sufficient. Obviously there needs to be some safety mechanisms in place here to prevent too much current flow, exposed conductors etc. My question is though, would the multiplus be happy with this power source as long as the multiplus did not draw more power than the inverter could provide?

Multiplus-IIoffgrid
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2 Answers
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JohnC answered ·

Hi @Urban caterpillar

This should be possible. I looked up the Multi's input current minimum settings, and the lowest you could go with that is either 3.0 or 3.7A (depends on model). Can be set in the GX. That's around 700-900W, so your other inverter needs to be happy with that. And indeed the vehicle battery it's drawing from.

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urban-caterpillar answered ·

Thanks John. That seems in line with my thinking. Program the GX device to draw a maximum current from the grid that is less than the max cont output of the inverter. As long as the battery and alternator can provide the power then in theory everything seems good.

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