question

Jan Goudriaan avatar image
Jan Goudriaan asked

Victron multiplus II 48V/5000 Valence Batteries Charging contact

am planning to use the multiplus 2 in a ESS using Valance U27-12XP lithium batteries.


These batteries have their own separate BMS, and this BMS controls contactor outputs. A Charge/Discharge and a charge control contact


The Charge/Discharge contact wil connect or disconnect the batteries from the Multiplus in case of a Failure.


The charge control contactor operates based on the value of VCell_Max. If VCell_Max > 3.8V the contactor output is disabled. If VCell_Max < 3.75V the output is enabled again. In this way the charge control contactor output will pulse off/on based on the value of VCell_Max and allow the cells to balance without overcharging.


My question is, is there a way to enable and disable the charger in the multiplus 2 using this charge control contact in combination with a separate relay and a input on the Multiplus 2

Multiplus-II
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2 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

yes, you can add the 2 wire bms assistant to the multi, and this gives you independent control of charge and discharge. Using a contactor to disconnect the supply from the multi is crude and not reliable - the inrush current will damage the contactor - particularly if it switches frequently.

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Jan Goudriaan avatar image
Jan Goudriaan answered ·

Thank you for the response, this helps with my design.

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