question

boekel avatar image
boekel asked

Battery voltage limits in ESS mode? (not discharging below 41V when grid available)

I'm testing batteries with an ESS system: Quattro 48/10000, Venus, CANbus BMS


When testing 12s batteries, in ESS mode the system discharges until about 41 volts, then tapering down DC current and holding voltage there. I've searched for sustain voltage, cut off voltage, etc., all is set to 36/37 volt.

when adding a load to the output, the unit uses grid-power to provide the load, actually going over the set Input Current limit.

Only when switching off the Grid, the system uses the battery down to the set levels (stopping at 37V)

Is there a setting somewhere I missed? or is it an undocumented feature?

some lithium batteries have quite a bit of capacity between 41 and 37 volts, it's good to know if we're able to use this in peak-shaving systems.

ESS
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lassestu avatar image lassestu commented ·

Did you find a solution for this? Having the same problem, starts using grid power from 41-40.8V. Only when I put the grid down it starts using battery power again all the way down to 37.2V which is acceptable.

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boekel avatar image boekel ♦ lassestu commented ·

No I have not, in practice I only use this part of SOC for backup use, so not a problem in real life for me.

But it would be nice if the system works as expected.

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lassestu avatar image lassestu boekel ♦ commented ·

Yeah I guess my system will be at the same level, the rest will be for real backup if the grid actually goes down. But I would like to know what parameter is limiting this, I cant find it in any documentation, so I would appreciate if any Victron staff replies with what parameter that is doing this, and why its not customizable.



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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

There are several places where settings or limitations could lead to this behaviour.

Could you please post screenshots of the following sections for your system?


Venus-device / CANbus Battery / Parameters


Venus-device / ESS / Minimum SOC


VE Configure / ESS Assistant / Sustain voltage




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boekel avatar image
boekel answered ·

Some settings and observations:


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markde avatar image
markde answered ·

hi,

Could anyone find a solution to drain the battery down to 37.2 voltage while running in ess mode? Hardware wise it should be possible because without Grid it discharges all the way down.


thx in advance!

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solartech12 avatar image solartech12 commented ·
did you find solution to this ??
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Related Resources

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