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hebs avatar image
hebs asked

Multiplus II overload alarm - battery discharge limited

I have two Multiplus 3000/48 II (one GX & one non-GX) in single phase parallel, with Seplos Smart BMS communicating through CANBUS. Has been working fine for a month or two but for some reason when set on “inverter only” it can no longer cope with even small surges of energy usage. It triggers an “inverter overload alarm” about two seconds after switching on anything that uses a bit more electricity than normal (kettle or hair dryer or oven or microwave). It has worked with these items in inverter only mode before and I am trying to work out what I have done for it to stop working.

The physical setup hasn’t changed but I have been playing around in node red quite a bit.

I did have an ESS assistant installed (on both as per guidance) with identical setups when it worked fine. I have also tried without ESS and it still trips on a higher load.

Has anyone come across this before, thank you.

Multiplus-II
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2 Answers
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mbotke answered ·

I'm looking in to spurious overload warnings as well - looks like there is a firmware update on Victron Professional.

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hebs avatar image hebs commented ·

For me, it isn't a warning, it is an alarm, causing the Multiplus to turn off.


I noticed a few posts so I updated from v497 to v500 today but the issue is exactly the same. It was working fine for two months on v497 before it started playing up. My battery is not throwing any errors so I must have changed a setting in my Victron for it to be doing this now.... or something may have blown inside one of the Multiplus's?

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nickdb avatar image nickdb ♦♦ hebs commented ·

Or you have a problem with one of your loads.

It the unit is shutting off and restarting after 30 seconds, you have exceeded its specs.

If you’re southern hemisphere, it gets warmer this time of year so the inverter will also derate. There can be many variables.

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hebs avatar image hebs nickdb ♦♦ commented ·
I have tried various different device loads and it faults at around 2,000w of load. Two Multiplus 2 48/3000/35 in parallel should be able to handle 6,000w continuous and 11,000w peak.


All cables are matched in length to balance between the two multis. I have followed the cabling guide written by Victron.


I have had it running with 6,000w off battery fine before but now it won’t get over 2,000w (ish) before it alarms/trips. That isn’t exceeding specs. All works as expected when switch is set to ‘on’ but it just isn’t playing above 2,000w when set to ‘inverter only’.



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hebs avatar image hebs hebs commented ·

I’m in the UK and it’s a steady 16C in the garage where the inverters and battery are located.

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hebs avatar image
hebs answered ·

I have tried many combinations of settings to try and figure out why I get an overload alarm. I believe that the cause is that my battery will only put out 50A max for some reason (apx 2,500W). So when on 'inverter only' and the demand exceeds that 50A, and it throws an overload alarm and turns off the inverter. I tried different set points to feed back to the grid (when switch set to 'on') and despite the set point being -6000W, it only ever discharged to a maximum of 50A (app 2,500W).


BATTERY: Lifepo4 - 190Ah - 15S managed by Seplos Smart BMS over CANBUS.

It is a 150A BMS and CCL is currently at 140A and DCL is at 145A. None of the BMS settings suggest a 50A limit and none of the BMS alarms/warnings have triggered.

The battery charges comfortably at 70A and I have previously had the battery discharging at 110A+ on 'inverter only' without issue.


I have not changed my BMS settings since it last worked correctly, but I have played with the Victron setup loads including node red.

Could one of my Multiplus's be faulty?

Is there a parameter/setting that I am missing that could limit battery discharge current?


Any steer would be very much appreciated, thank you.

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