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jerrylcaldwell asked

MultiPlus shuts down while on shore power after bulk charge is complete

We are out for the first time in our RV after installing a new MultiPlus 12/3000/120 and three SOK 206 AH batteries. When the batteries are near fully charged the multi turns itself off terminating all 120v shore power to the RV. I have witnessed fairly large voltage (14.2 to 12) drops during these events which may be causing the MultiPlus to cycle off. I cycled the 3 SOK 206 AH batteries and went through a bulk charge. Shortly after entering absorption the unit cycles off and on just as it did before discharge/charge, terminating 120 volt shore power. The MultiPlus will handle moderate 120v loads without shore power but turns off when the air conditioner compressor kicks on.


I don’t understand why the MultiPlus will not allow shore power to pass through as described in Victron documentation. Disappointed in the system so far.

multipus
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Paul B avatar image
Paul B answered ·

My best guess is that the batteries you have are NOT been fully topped balanced and a cell in each battery is going HIGH and thus the batteries are turning off. reduce the bulk and float charge voltage's to say 13.7, leave it there for a week then increase it to 14v leave for another week

then reset the battery type to lithium - battery type

you will need a MK3 or a cerbo/gx unit connected to the vrm

This would be my guess, read up on how to top balance those batteries. cycling them wont help - the cells will need to be fully top balanced.


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jerrylcaldwell avatar image jerrylcaldwell commented ·
Paul, thanks for the input. I had DCL On and heard that this might be the problem. I turned it off early this morning and the charge finally made it through absorption and into float for the first time. We are camping this weekend, but I will also go through your process as well.


I had A thought during the night that it might have been one BMS shutting down from the high temp sensor and causing the issue. it was really hot here in Texas yesterday. The batteries were allowed to set over night with no load and were at 24C this morning. I connected shore power and turned the MultiPlus on and it shut down in less than a minute. Once DCL was off all seems to be good. Thanks again
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