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Help Setting Up 24v System In RV

We have been struggling to figure out all of the components needed to setup a 24v system in our RV. We have 4 255w solar panels, Victron Multiplus 3000, Victron 150|35 MPPT, and after much debate between Tesla modules, and Battleborn batteries, we are going with Battleborn.

We have also been looking at the Orion converters but do not know whether to go with an isolated or non-isolated one. We also were looking at the Victron Octo GX to control it all.

The RV is currently powered via 30A service. It would also be nice to change the batteries off the alternator while driving.

Thank you!
Holly & Dustin.

campervanschematics
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3 Answers
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Kevin Windrem answered ·

You might get away with a non-isolated 24 to 12 volt converter for your loads. It would require a common negative for both systems.

If you want to charge from your alternator, you'd need a second DC-DC converter to go from 12 to 24, and that one would need to have a charging algorithm.

You can also go with a 12 volt DC system for your Multi and charge controller. It means larger conductors to handle the 2x currents but does eliminate the 24 to 12 volt converter. I would only do this if the inverter and batteries are located close to each other.

Even with a 12-volt house bank, you'd still need the DC-DC charger to charge from the alternator.

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sasquatters avatar image sasquatters commented ·

So would an isolated converter be better? Does Victron make the 12 to 24v converter to mention?

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Kevin Windrem avatar image Kevin Windrem sasquatters commented ·

Victron makes a lot of different DC-DC converters and chargers. The line is named Orion.

Isolated would be better in that you don't need to pay so close attention to the negative bussing between starter and house systems. Isolated are a little more expensive than non-isolated. Depending on the power requirements, you may need to go with non-isolated.

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ah64id avatar image
ah64id answered ·

What are your goals for going 24V vs staying with 12V?

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sasquatters avatar image sasquatters commented ·

Our panels and all components are for 24v. More efficient charging.

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Kevin Windrem avatar image Kevin Windrem sasquatters commented ·

Your solar panels are going through an MPPT controller so the battery voltage isn't tied to the panel voltage. As long as the panel voltage is higher than the battery voltage (plus 5 volts), the controller will efficiently convert the solar power to the battery power.

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ah64id avatar image ah64id sasquatters commented ·

As mentioned you do not need to have a 24V battery bank with that setup.

Switching to a 24v battery bank will either take all new lights/DC appliances or a step down transformer. Neither of those options are easy and you really don't gain anything, not even more effecient charging with that MPPT controller.

Stick with a 12V setup, use that MPPT controller and it will charge as efficiently as possible.

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Kevin Windrem answered ·

I missed the point about the Octo GX. The Octo GX has no display, so you need to use a tablet/computer/phone and access the GUI via a web browser.

A better choice would probably be the Cerbo GX. Cerbo also has no display but the Touch 50 companion touch screen is available if you decide you want a dedicated display.

Another approach is the Color Control GX. It's an older product with no analog or digital inputs but could fit your need as well.

I recommend a GX device, but you can also use VictronConnect: A smart phone/tablet app that communicates via Bluetooth. VE.Smart Networking then provides a more limited integration than a GX device.

You should also incorporate a battery monitor (BMV series or Smart Shunt) to monitor battery state of charge. (The Multi calculates SOC but assumes there aren't other loads or charging sources so is not appropriate for this type of system.)

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