geordi avatar image
geordi asked

Smart Solar and Multiplus with Cerbo or Color Control in an RV?

I'm looking for help building an integrated solution that will not overcharge the batteries in my RV.
I have: 3 panels of solar for 1020 watts, connected to a Smartsolar 150/85. I also have the VE.Direct Bluetooth b/c of where this unit is positioned relative to where I prefer to monitor b/c of bluetooth range.
Magnum Magnasine 2812 inverter charger
Magnum battery monitor
Onan QD7500 diesel generator
8 GC2 golf cart batteries set up as a 12V array - Because this is an RV, this MUST remain a 12V system.

My issue: With near continuous 4-5 amp load out of the batteries, I'm not sure that the Magnasine is charging properly with the generator running, or that the solar is not overcharging the batteries at the same time b/c it only has the voltage to monitor - no battery monitor (yet?) on the Victron side. During a 2 week period with the generator running 24/7, the batteries used a total of about 2 ounces of water per week each, or about a quart for the array over 2 weeks. To me, this seems excessive.

I'm thinking about a complete system with the Multiplus 2000 or 3000, the new Cerbo or Color Control.... What I would like is a centrally controlled system where ONE device knows everything going into or out of the batteries and manages the needs with monitoring. Is this possible? Do I need a BMV for that? Does the Cerbo or Color Connect do this with the added benefit of internet / remote monitoring possible?

Multiplus-IIMPPT Controllerscerbo gx
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2 Answers
ejrossouw avatar image
ejrossouw answered ·


The MPPT should not be overcharging the batteries if configure with the correct parameters. I cannot personally comment on the other equipment.

How old are these batteries and how balanced is your bank. A bad battery can definitely adversely impact the system and charging. Well worth exploring that option too, as throwing good equipment at bad batteries will still not solve a battery problem.

As for you ambitions to install a complete Victron solution, good move. It will easily serve all your needs and possibly more. See the Victron VRM demo to get a feel for the remote monitoring and management possibilities. There are multiple choices in the GX range you can opt for and maybe hop over to

to see what fits your requirements. I'd personally suggest to look at comparison sheet to see what ports etc you will require.

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geordi avatar image
geordi answered ·

The batteries aren't that old, although they are not all the same age. Power from the array is very good without the generator running, it is able to run my large compressor fridge overnight on around 20% of the SoC according to the Magnum battery monitor.

The charge voltages are set according to Interstate Batteries who made these. My concern is that the charger logic MAY not be taking into account the load (which it should be able to detect by communicating with the battery monitor) as it seems to spend many hours in absorption mode.

My main questions I guess with the Victron system - Will the GX - either Cerbo or Color Control - "take over" the logic and control of the charging and take into account the active loads while deciding what charge profile to use at any given moment?

1 comment
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ejrossouw avatar image ejrossouw commented ·

I propose you have a read of the below as it explain how it works. Hope it helps.

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