question

praxe avatar image
praxe asked

Absorption voltage can’t be reached

Hi guys, I have a VictronConnect multiplus 2 12V 3000VA that is hooked up to two Ultimatron 150Ah lifepo4 batteries.

I have set the absorption voltage according to the battery specifications to 14.6V. Nevertheless the BMS kicks in at around 14.2V and stops the charging the process. All the cells seem to be pretty good balanced.

The multiplus stays at 14.6V and does not drop down to float voltage (set at 13.8V).

The batteries are new, do they need to get a few cycles until they reach full capacity?


thanks in advance

br lukas

Multiplus-IIlifepo
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4 Answers
thanar avatar image
thanar answered ·

If the BMS is kicking in, then there is a cell that goes higher than it's supposed to. How to you know that "the cells are pretty good balanced"? Do you have some insight on the BMS data?

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praxe answered ·

Yes I can see the cell voltage via the Ultimatron app. They are all in a range of +/- 0.005V. Maximum delta between the highest and the lowest is 0.008V


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rikhf answered ·

How is the charging process stopped? By switching off the BMS or by telling the Victron system to reduce charge current?

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praxe avatar image
praxe answered ·

Via the BMS. The Victron system stays at 14.6V, I guess until the maximum absorption time is reached. Then the system stays at float voltage 13.6V.

Battery voltage drops from 14.2V to 13.6V.

SoC from the batteries also slowly drops from 100% to 97%, even when the multiplus is still in charging/float mode.

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Related Resources

Additional resources still need to be added for this topic

MultiPlus-II Product page 

MultiPlus-II Manual

Multiplus-II GX Online Manual

MultiPlus-II 230V Datasheet 

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