Multiplus II shutting down

DIY
, , , ,
1

Hello, I’m having an ongoing problem with my 12/2000 Multiplus (on a new to me boat) not being able to put out more that 900 -1000 watts before shutting down with a low battery warning.

The unit will cycle, shutting off for a few seconds before restarting. It’s connected to 600 Ah of AGM batteries. Measuring across the inverter terminals the lowest voltage I’ve seen is 12.1v when it’s drawing 100ish amps. Measuring at the batteries gives me 12.3 v. All connections seem good.

I went into Connect and made sure the DC input low shutdown was set sufficiently low (10.75v) but, doesn’t seem to make a difference.

There’s a Cerbo and BMV in the system with DVCC enabled.

Any suggestions on what to check next? Possible bad unit?

Screenshot_20260509_061425_Chrome
Screenshot_20260509_061425_Chrome1057×1564 101 KB

20260508_103100
20260508_1031001920×3410 1.62 MB

20260508_102837
20260508_1028371142×1630 528 KB

2

Check all your connections are tight (properly torqued) and that your crimps and terminations are excellent. If they are, then monitor your DC ripple with VE.Configure or a custom widget in the advanced section of VRM. Most likely you have something insufficient on the DC input side of the inverter.

3

Thanks, all connections seem tight and clean. I’ll create a dc ripple widget and will keep an eye on that. What’s considered excessive ripple?

4

Have you read the manual? :slight_smile:

Screenshot 2026-05-09 at 10.04.29 AM
Screenshot 2026-05-09 at 10.04.29 AM2362×208 30.7 KB

Here’s my DC ripple for the system in my shop today while charging my car at a steady 9kW:

Screenshot 2026-05-09 at 10.07.55 AM
Screenshot 2026-05-09 at 10.07.55 AM952×1026 93.5 KB

This is from a 3-phase system with three MultiPlus-II 48/5000 120V inverters.

In my view, 1.25Vrms is far too high for a properly designed system. Post your DC ripple graph once you have it set up.

5

You might also find Victron’s “Wiring Unlimited” booklet interesting: https://www.victronenergy.com/upload/documents/The_Wiring_Unlimited_book/43562-Wiring_Unlimited-pdf-en.pdf

There is a discussion of DC ripple caused by the PWM switching used to make the AC waveform.

6

Update on my Multiplus shutdown issue. It continues to shut down at about 1000 watts output. No low voltage or other alarms were logged. Ripple voltage measured with my non RMS meter at shutdown was around 0.5v with the BMV showing batteries at 12.4v. Also seeing approximately 0.5v ripple on my multimeter while charging at 60-70 amps.

I set up a custom widget to monitor ripple voltage in VRM and for some reason it says “no data to display.” I’ll have to work on that to try and figure out why it isn’t recording.

20260512_101126
20260512_1011261920×3410 1.15 MB

20260512_101536
20260512_1015361920×1905 854 KB

7

What wire gauge did you use for the DC cables going into the Multi? What did you use to crimp the lugs on the cable?

8

0.5v equals a approx1v reading difference. So at 12v it will see 11v.

9

I believe the cables are factory installed when the boat was built in 2007. The multiplus unit is about three years old. It looks like they’re all 4/0 with about 7’ on each side +/- from the battery bank to the inverter.

10

4/0 is certainly plenty for a 2kVA inverter. Regarding your ripple widget, sometimes you have to change the data interval on VRM and then change it back to something else to get data to show on the graph. As @lxonline said, 0.5V is a lot for a 12V system in my opinion. That’s large in percentage terms. I’m eager to see the data.