question

crop1 avatar image
crop1 asked

ESS / Batrium BMS - feed back to grid why?

I have a multiplus 48/5000 it is grid connected and charges a 58 volt lithium battery made from a 24kw nissan leaf battery, I have a Batrium BMS.

I have 2 issues, my first issue is if I ask the system to charge the battery to a high voltage, for example 57 volts, upon reaching this it sometimes then discharges the battery back into the grid, if I catch this and switch the inverter off and on again it acts normally.

My second issue is with the batrium bms, setting the battery percentage charge. for eample if i set say 55v at 80% charge, within a few short weeks it will sink to say 53v is 80%. this causes the battery to charge less and less and I have to keep re setting the volt/percentage.

MultiPlus Quattro Inverter Charger
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1 Answer
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Crop1

I've moved your question to the more appropriate section, and changed the title to make it more clear.


feed-back to grid: this probably happens when the BMS lowers the CVL, your inverter gets the lower CVL and when actual battery voltage is higher, it will discharge until it reaches the new CVL.
Note that when doing this all limits are ignored! and so you probably want to prevent this by changing the BMS parameters.
(on an LFP battery this is no issue because of the different (dis)charge profile)

the second issue, you'll probably have more chance of a good answer on a Batrium forum, but who knows, there might be someone reading here that knows how they work.

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crop1 avatar image crop1 commented ·

what value do you think i should set the cvl to ?

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ crop1 commented ·

Hi @Crop1

I cannot advice you on that.

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