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sprinter2023 avatar image
sprinter2023 asked

Voltage bouncing up and down with MultiPlus 3000VA 12-Volt

I have a the Victron Energy MultiPlus 3000VA 12-Volt Pure Sine Wave Inverter and 120 amp Battery Charger, Today the voltage and amps keep going up and down, even if I turn of the power to battery

I have had this installed and working from the middle of November, I have unplugged the cat5 cable the had the dongle plugged to it, any suggestions to fix this ?



bmv-712-voltage.png


voltageamps
bmv-712-voltage.png (172.4 KiB)
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sprinter2023 avatar image sprinter2023 commented ·
I did a restart on the BMS and the looks like it fixed the problem
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2 Answers
Trevor Bird avatar image
Trevor Bird answered ·

@Sprinter2023 I am guessing your batteries are Lithiums with an internal BMS. If that is the case, I suggest you may lower your absorption charge voltage and see if you can settle down the BMS. If the batteries are not lithium, that is a different matter.

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sprinter2023 avatar image sprinter2023 commented ·

It still does it when I turn of the battery disconnect

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sprinter2023 avatar image sprinter2023 sprinter2023 commented ·
yes, they are the Lifepo4 12v 906ah
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Trevor Bird avatar image Trevor Bird sprinter2023 commented ·
That is unusual to see that if the batteries are just sitting there isolated from everything. I am not sure where the current is going if the batteries are not connected to anything.
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Paul B avatar image
Paul B answered ·

The BMS is turning the batteries off as one cell is going over its max limits. - to help stop the issue - reduce the Absorption voltage to say 13.7 or lower if needed to stop the on off issue that the BMS is doing - then look at the cell voltages of your batteries and slowly adjust the voltage up as the high cell voltage reduces . max cell voltage would be around 3.65v on any one cell. another way is to use the DVCC in the gx unit and reduce the charge amps to 1 or 2 amps and see if that brings it under control. once the total volatge gets to 14.2 then you should again slowly raise the volatge to 14.5 or until all cells are close to 3.65 then reduce the volatge back to norma SETTINGS


This points to unbalanced cells


ps IT MAYBE better to play with the DVCC and reduce the max charge amps this maybe easer as the adjustement can be done in the GX unit under DVCC

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sprinter2023 avatar image sprinter2023 commented ·

would the bms affect the inverter/charger when i turn off the battery disconnect

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