MultiPlus 12/3000: runs only with AC present, dead on battery, resets under charge load

DIY
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1

Ran into a new issue with my Multiplus 12V 120V - 3000 VA (Standard) purchased in 2019 and installed in a campervan. 2/0 cables, 600ah bank.

Right now, the unit only powers on when shore power is connected. With AC present, it behaves normally - the MultiControl responds, both charger-only and ON modes work, charging and inverting both work. If I remove shore power, the entire MultiControl panel goes dark, and the unit is completely dead. There is no light on the Multicontrol at all on battery and the switches do nothing.

Separately, while charging on shore power, it resets itself and does not throw any errors on the LEDs. It resets itself in ~5 mins with the input limiter at 5A, and about 2-3min with the input limiter at 16a. Tested two different separate AC circuits to rule out upstream power.

I have tried different batteries to rule that out.

High DC current clearly passes through the DC path in both directions, which is why I don’t think there’s an open or high-resistance connection between battery and unit. Feels like something is actually wrong with the unit itself, but id love to diagnose that before sending it back in…

Thanks in advance for any help!!

4

If the MP is only running on AC, even with another and flawless battery, I should suspect that there is something wrong with the MP. Maybe you should contact your local Victron dealer, if they can inspect and repair the MP.

5

Check the MP’s internal fuse.