eugenioschloss avatar image
eugenioschloss asked

Mobile off-grid design Challenge

Dear VE Community,

I am seeking your expert advice on a custom project that I am currently designing for a trailer application. I would appreciate your feedback on whether the design meets the requirements or if I need to make any changes.

Here are the major specifications of the system:


  • The system must be able to receive power from both one AC source (such as grid or diesel generator) and DC source (such as solar panels).
  • The system will primarily operate in off-grid mode, with "Storage" batteries used as the main power supply.


  • The system includes two "load" batteries rated at 24V and 22Ah each, which should receive a constant current between 10A and 20A to be replenished.
  • Additionally, some DC loads and AC loads needs to be fed with power. These loads are on demand and not constant baseline.

Please note that the "load" batteries are not intended to reverse energy back to the system. Instead, they will be discharged elsewhere. Think of the system as a continuous battery charger on wheels!

My current preferred design uses a Victron Multiplus II 24/3000 combined with 2x Pylontech UP2500 and a Lynx Distributor. Two DC-DC 24/24 chargers would be installed between the Lynx Distributor and the "load" batteries to charge them. According to my calculations, I should be able to replenish the "load" batteries around 4-5 times each.

I have attached a high-level schematic of the system for reference:


I would greatly appreciate your input on the feasibility of this design to fulfill its intended purpose and any potential improvements you may suggest. Any suggestions and tips before I move forward with more detailed design would be invaluable.

Thank you in advance for your assistance!

Multiplus-IIbattery chargingPylontechoffgridcampervan
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matt1309 avatar image matt1309 commented ·
I'm no expert but looks good/feasible to me.

The only thing I'd flag is "DC Power from solar" assuming it's solar via MPPT you would normally wire that into Battery/main DC bus bars (Lynx Distribution) rather than into the multiplus, however you may have just done that for ease of diagram so please ignore comment if that's the case.

I'm not too familiar with Orion however I'm not 100% sure it integrates with Cerbo/venus os so monitoring that in cerbo may require a smart shunt however I'm sure someone else can clarify on that.

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kevgermany avatar image kevgermany ♦♦ matt1309 commented ·
Correct, no monitoring of current in the orions
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eugenioschloss avatar image eugenioschloss matt1309 commented ·
Hi, yes good point. Solar will be linked directly to the distributor. Unfortunately Orion does not connect with the Cerbo GX so I need to get a bit more creative there.

Thanks for the feedback!

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matt1309 avatar image matt1309 eugenioschloss commented ·
Pretty sure a smart shunt monitoring can monitor DC loads now. Chuck one of those in and you should be good.,
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kevgermany avatar image kevgermany ♦♦ matt1309 commented ·
Yes, needs to be setup for it. But no control possible for the Orion.
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