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Robert Boerescu avatar image
Robert Boerescu asked

Un-managed Battery with ESS

Hi everyone! After reading a lots of posts here and watching videos on youtube and going through Victron Professional online videos I do not seem to find a proper answer on how to setup a LIFEPO4 with multiplus 2 and ESS if the battery has an internal BMS in a box with no possibility of communication. Right now It is set as AGM but the fact that it is showing as float when it should be bulk is annoying and I am not sure if there may be other implications.

I have an EasySolar2, SmartShunt 500Amp, 4x455w half cut panels and 48v 15s 100amp Chinese battery with internal BMS. I use 52V for charging and 51 for float. I use AC Output 1 for critical loads, mostly computers routers and stuff. This is mainly for backup because there are a lot of power cuts.

I have another Fronius Symo Gen24 plus 5k with 14x455w panels AC coupled but they do not communicate (no integration with Victron).

I do not want to spend money now for a new battery and I am looking for the best way of making use of what I have.

I read that for lithium when it goes down 0,8 V from the charging voltage is going back to bulk but probably for AGM this is different and this is why it stays on FLOAT.

I can upload the config if anyone wants to have a look.

Multiplus-IIEasySolar All-in-One48v battery
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4 Answers
Alexandra avatar image
Alexandra answered ·

@Robert Boerescu

You can use a lithium battery profile, then change the target voltages. That will work better. Then the rebulk offset is closer and temperature compensation is off and there is no equalisation.

I have many batteries with no comms running ESS without issues this way.

Your voltages are the same as Pylontec based systems so should be fine.

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Robert Boerescu avatar image
Robert Boerescu answered ·

Thank you, @Alexandra

I was thinking about doing it but the options in the lithium ESS settings are not very obvious for a battery without comm. Option “other BMS” will not give errors like not able to communicate with BMS or stuff like this?

Thank again for your help.

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Alexandra avatar image Alexandra ♦ commented ·

Use System uses lifepo4 with other type BMS. No errors like bms lost will be an issue.

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Robert Boerescu avatar image
Robert Boerescu answered ·

I changed it and so far so good, I am keeping an eye on it....

screenshot-2022-11-29-084652.png


screenshot-2022-11-29-084652.png (46.8 KiB)
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Robert Boerescu answered ·

All seems to be good, I also tested a turn off turn on the easysolar and it worked fine, It did not come up with bms comm errors and stuff which is what I was afraid of.

The first time I powered off and on, for some reason, the internal ve direct conection to the MPPT did not work and the solar charger was not showing up in vrm but it was actually working. I did a second power off power on and it came back ok. Strange. Hopefully it will not do it again. I looks like with great customizability come some bugs also :-)

It is good that it can work properly without having a compatible bms because the batteries in the compatibility list while very good, tend to be very expensive at least here in Turkey.


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