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piano-guy asked

How to set up Multi Plus compact 12/2000/80-50 120v for Li battery

Hello Everyone,

I am installing a Multi-plus Compact 12/2000/80-50 120 v into a camper. I have 2 new 200 ah SOK Lithium batteries connected in parallel. I used the (interface USB) to connect to my computer and adjusted the Multi-plus for Lithium batteries. The charge voltage should be 14.4 volts but when I measure the voltage with a meter it never goes above 13.64 v. The Smart Shunt confirms this. Is there something wrong with my Multi-plus, or have a missed something in the setup?
After adjusting the charge voltage in the software I turned off the system and restarted it to make sure the settings actually took place. Everything showed good and seemed to reflect the new charging voltage of 14.4, but it still does not reach that level.

After letting the batteries charge for a few hours, I tried to see if the inverted would power my microwave oven. The smart shunt shows that it was drawing slightly less than 1500 watts and then the inverter shut off after just a few seconds. The battery voltage was dropping down to about 10.5 volts before it tripped off.

Did I get a bad Multi-plus, bad batteries, or just miss something in the setup?

Any advise you can give me would be appreciated.

Thanks,
Roger Lilly

MultiPlus Quattro Inverter Charger
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2 Answers
Kevin Windrem avatar image
Kevin Windrem answered ·

In VictronConnect, make sure the charger is enabled in the Muiti config and that the charge current is set to match your battery's maximum charging current (or the max the Multi can produce if that is less).

The Multi should then enter Bulk mode unless the Absorption or Float voltages have been reached.

If you don't see any charge current, try charging the batteries with an alternate charger to see if they accept a charge from another source. That will tell you if the issue is in the Multi or the batteries.

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rmaddy avatar image
rmaddy answered ·

I have the same two SOK 206Ah batteries. But mine are setup in series for a 24V system. I am using the BMV-712 instead of the Smart Shunt and I have the 24V/2000/50-50 120V MultiPlus.

Here are relevant pictures from VictronConnect that are working for me. Of course you need to divide all of my voltage settings by 2 since you have 12V versus my 24V. And your battery capacity is 412Ah since yours are in parallel. Everything else should be basically the same.

Here's the Battery settings for the BMV. The Smart Shunt has the same settings screen. Again, change the Battery capacity to 412Ah and change the Charged voltage to either 14.1 or 14.2.

img-2628.png


Here's the Charger settings screen from the Multiplus. Change the Absorption voltage to 14.3V and the Float voltage to 13.6V. And of course make sure you have enabled the Lithium batteries setting.

vcmultipluscharger.png


If you also have the Smart Dongle for your Multiplus for Bluetooth, setup VE.Smart networking for both your Smart Shunt and Multiplus so they can share some data between them.

Once you get this all setup, connect the AC In on your inverter and charge the batteries. Let it fully complete the Bulk and Absorption phases. Depending on the real SOC of your batteries, the Bulk charge could take several hours and the Absorption is setup to run for 1 hour. Then it will switch to Float. Let it get that far. The SOC may show 100% long before it gets to that point but that's fine. Let it complete regardless of the SOC shown up to that point. The SOC will be properly reset to 100% when it is really fully charged based on the Charged voltage, Charged detection time, and Current threshold. During the hour of absorption charging, the voltage should show a steady 14.3V (+/- 0.02) and the current should drop steadily towards zero.

Hopefully after that complete charge, everything will work correctly for you.


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