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wolfbarnsolar avatar image
wolfbarnsolar asked

Combined the AC Output of Two inverters with Separate Battery Banks & Chargers

Had an Idea! to use my 2 Systems & combine the AC output to off grid home & Sheds

I have 2 Separate banks of 48v Battery's of different Types OPzV 2v & Wet Cells 6v (so can not be Combined I believe)

2 Separate solar systems supply charging (1 Multi via solar charger 1 other brand inverter) to 2 Buildings on separate supplies

Currently both systems supply a building each,

Multi has Gen connection for backup charging

Can I combine the AC output from both Inverters to the Home & Sheds as one Supply (drawing from Both sets of Batteries)

I understand (believe) i can only charge 1 battery bank from the generator but would like someone to confirm or deny this

Is this feasible & is there a better way ???

Multiplus-II
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2 Answers
Elimac avatar image
Elimac answered ·

Hello

I also am interested in alternative ways of maximizing the use of Victron gear, specially those modes that could enable to add extra battery capacity.

I don't know the full answer, but as far as I know at the moment, two issues come to mind:


1) You need to make sure both inverters are in SYNC, so the output wave is in phase on both outputs. If not, I don't know what can happen, but you could end up with more than the desired VAC, or less too. How to achieve this? besides using the standard parallel connection, I am not sure, but I could think of just feeding on the input a sample of the VAC wave... or joining just the neutrals? Not sure if it works


2) second issue is how to balance the power to loads from both systems. I have no idea what will happen, which inverter will provide most power? How to balance?


The best you could do is a cascade configuration, IN from first connects to GRID or Generator, OUT from first connects to IN of second. Both OUTS could feed their own loads, and bigger loads connect on second inverter and you make use of powerassist.

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boekel avatar image boekel ♦ commented ·

Cascading is the only way that it can work, Never combine outputs!!

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wolfbarnsolar answered ·

Hi Elimac

Yes I realize the same issues after further contact with my friendly electrician

But interested in the cascade configuration

Hi Bokel

Thanks for that any further info would be appreciated

Assume the battery bank on inverter 2 is charged as if it were on GRID (set via CCGX Parameters for Grid connect) Inverter 1 is set up as Generator Backup

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Elimac avatar image Elimac commented ·

Remember, in my opinion the cascade configuration should be regarded as a series of 2 complete systems, and hence maybe better to use one CCGX/ Venus for each one. I don't know if is possible to use the same CCGX. If so, I am also interested as it would make monitoring better (same site).

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