question

philipl avatar image
philipl asked

Multiplus II and Battery current limiting

Hi,


In an installation where a Multiplus II 48/5000/70 and single BYD 2.5 battery will be used as a UPS, is it possible to set the maximum battery discharge current to protect the BYD battery? The BYD battery spec says discharge should be limited to 2.6kw. So the Multiplus will be connected to the grid, and the BYD battery will serve to provide power if the grid goes off. The system only need to be able to supply about 2 to 2.5kw max.

So is it possible to set the maximum discharge current from the battery to 2.6kw, or otherwise, can the Multiplus be set to output to a maximum of 2.6kw?


Thanks

Multiplus-IIBYD
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3 Answers
sean avatar image
sean answered ·

Within the ESS settings there is an option to limit inverter power.

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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @philipl

When the grid fails, there is no limit other than what the inverter can do (incl overload capacity), that is why there is a minimal number of batteries specified for off-grid, etc.

https://www.victronenergy.com/live/battery_compatibility:byd_b-box#minimum_battery_sizing

The only way to limit the current, is to limit the users on the output of the inverter (you could install a low current breaker on the AC1 output.

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philipl avatar image
philipl answered ·

Hi @Daniël Boekel (Victron Energy Staff), thanks for your answer. I just want to make sure. Are you saying that even if I limit the inverter power in the ESS Settings, that the inverter will ignore those settings if the grid fail? So the inverter will then operate at up to maximum capacity when the grid has failed? Which could then overload the single BYD battery.

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