Multiplus 2 low voltage alarm regardless of battery being at 100%

Q&A and troubleshooting
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1

Hello,

I understand this topic has been brought up many times, and I have not been able to find a solution to my particular issue. I am stationed overseas in Germany, I have an American Camper. I have installed a 3X 330 Lifepo4 12V battery (BMS 200 amps) system connected in parallel using 2AWG size wire, since I am unable to use the European 230V for my appliance. My system consisted of a Cerbo GX, 2 X 100/30 MPPT for roof solar and portable solar, a battery smart shunt, Orion XS 50A, and a MultiPlus-II 12/3000 120.

I have been constantly getting Multiplus 2 low battery voltage (code 276), even when the batteries are at 100%. I installed the system using 4 AWG wires. I checked and triple-checked all bolts and tightened them to specs, no loose wires or damaged wires. The moment I initiate an AC load between 10-15 amps, I get a low battery alarm, and the MultiPlus restarts. I have reset the Multiplus to default and reconfigured it with these configurations, and still the same issue.

General: AC input 25 AMP and check the overruled by the remote; checked the dynamic current limiter

Grid: left it as is since I am not providing any power to grid.

Inverter: Inverter 120V; Power Assist is checked with 2.0 factor; ground relay is checked, DC input low shutdown 11.0v

DC input low restart 12.5V; DC input pre-alarm 12.50V.

Charger: Enable charger is checked; Lithium battery is selected; Absorption voltage is 14.4V; float voltage is 13.8V; and charge count is 120A. Repeater absorption time is .25hr, 7.00 days for the absorption interval, and absorption time of 1hr.

Can someone provide some insight on how to fix this issue, please?

2

Not 4/0 awg? For a 12vdc 3kVa the 4/0 (or 2x1/0 -50mm²x2) is more appropriate.

How long are the cable runs? You may just be getting volt drop?

3

Correct on the 4awg wire. I ordered 25mm2 wire, which is equivalent to 4AWG. Due to my camper’s limited storage space, the batteries are toward the front and all Victron components are in the rear. I use 20 feet of wire. I thought that could be an issue with wire size, but hoping it wouldn’t be. 4/0 is 107mm2 and Amazon.de doesn’t sell it; I would need to order it from Amazon.com. I will check with a bigger wire size and let you know in a few weeks. Thank you for the reply.

1 Like
4

For 20ft return path that is pretty long. See if you can go even larger (or make a double run of the cable). if you plan on using the full 3kVa potential.

2x 50mm² is just enough to run a full load comfortably for under 5m return path.