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malcolmdmoore asked

VE.Bus Error 5 Overvoltage on AC-Out

Setup (in an RV):

* 2x MultiPlus 24/3000/70-50 120V set up in master-slave configuration
** One each connected to a circuit breaker panel
* SmartSolar MPPT 150/70
* Color Control GX
* BMV-712

AC panels have loads distributed across them. Included among these are two RV aircon units, with soft-start capacitors added. When I run a specific RV aircon unit, which is on one panel, and another high-wattage device on the other panel, I get VE.Bus Error 5 and the accompanying 30-second shutdown of all AC loads.

Testing so far:

* Seems to be centered around the interaction between the inverters, one of the aircon units, and the solar system.
* Only happens when inverting. When on shore power, no issues.
* Seems to only happen when the compressor on the AC comes on.
* Second AC unit does not appear to generate the problem.
* Load at the time is anywhere from 1600 - 3000 W, depending on what I have running. Seems to initially require me to put a heavy load on the system, then I can get it to happen with solely the AC unit in operation.
* Slave unit always displays the fault. This inverter drives the aircon unit that I can generate the fault with.
* Have not tried cutting out the PV controller far have only cut the panels out (400A panel cutout switch, 80A controller cutout switch)

Any ideas appreciated.

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malcolmdmoore avatar image malcolmdmoore commented ·

Update: With MPPT 150/70 fully defeated, problem persists. We will start with the simple stuff, checking the wiring between the two inverters next.

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Can you please post a wiring diagram of the system?

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2 Answers
malcolmdmoore avatar image
malcolmdmoore answered ·


Will add a diagram shortly. Have been wanting to answer this for a while but have been super busy.

In essence, the tl;dr is to "check your AC wiring" as the manuals say. The problem is, of course, where and what to check.

In my case, the problem was that my AC cabinet was wired up as two separate circuits, with one inverter driving one and the other driving the other, from when the system was originally designed to have a "shore power" circuit which only energized if grid power was present, and an "inverter" circuit that powered lower-load devices from batteries.

When I loaded up one circuit, the voltage on it dropped, to the point where the inverter on the unloaded circuit detected a voltage disagree which caused it to throw the VE.Bus Error 5. Since both units were connected to operate as one, both circuits dropped when the error occurred.

The solution was to rewire the AC panel as a single circuit. After speaking with Victron and Battle Born Batteries, the vendor we worked with, we determined that the lower voltage on the loaded circuit made the inverter on the unloaded circuit think there was an overvoltage condition.

We rewired the AC panel as one circuit, and haven't had a single problem since, even taking the inverters up to a combined sustained 7800W for 10 minutes.

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neoneddy avatar image
neoneddy answered ·

I think I've got the same issue going on. I also have two AC lines running to my panel. Seemed logical at the time. What gauge wires is running to the panel now? I might need to upgrade.

Also, then how to connect each multiplus? Run them to a small combiner / junction box close to them? Run them into each other and skip a junction box?

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Related Resources

What is VE.Bus?

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