Battery Protect charge disconnect - over voltage from charger

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jonathanv asked May 1, '23

Battery Protect charge disconnect - over voltage from charger

I have wired a Smart BP 220 as charge disconnect for my LFP batteries as per the Victron manual. It has a Phoenix Smart IP43 50A charger and two 100/30 Smart Solar MPPTs feeding into the In side. My issue is that if I disconnect the load output while the charger is active, it's output voltage will rise close to and sometimes over 16 volts and the BP will then not always allow reengaging as it is in Over Voltage protection (16v).

I have noticed that if I have the charger leave the VE Network (with a BMV 712 and Smart Battery Sense), the charge voltage will drop to 13.8 volts.

What should I do to ensure that if the BMS disconnects the charge BP, it then later will be able to reengage and not get stuck in over voltage protection, while preferably also still being part of the VE Network? Is there a way to set a max voltage out on the charger?

Lithium Battery Battery Protect Phoenix Smart Charger ip43

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Answer 1 · 2023-05-02T02:28:07Z

mvas answered · May 02, 2023 at 02:28 AM

Are you saying that your Phoenix Smart IP43 50 amp charger, continues to charge the LFP battery up to 16 volts? What are your charge voltage settings for Bulk, Abs & Float? Which charge "mode" is allowing 16 volts? How many amps are flowing when it goes above ~14.4 volts?

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jonathanv commented · May 04, 2023 at 03:52 PM

What I mean is that if the Battery Protect disconnects the charger (for whatever reason, be it manually or remotely through the BMS) the voltage on the charger output spikes to 16+ volts. The Battery Protect then wont allow it to reconnect as it goes into overvoltage protection. I have to physically turn of the mains power to the charger before I can reconnect the Pattery Protect and then turn the charger back on.

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Answer 2 · 2024-04-16T07:19:28Z

stu-co answered · Apr 16 at 07:19 AM

Hi, did you end up finding a solution to this or getting to the bottom of it? I suspect I'm suffering from a similar situation. I find it strange that the BMS is disconnecting the chargers in the first place but this might be due to a fault charger.

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jonathanv commented · Apr 18 at 12:13 PM

The only solution for me was to keep the charger out of the VE Network. My suspicion is that when the Battery Protect disconnects, it still sees the voltage sense from the Smart Battery Sense and then raises the voltage to keep it charging, not knowing it is no longer connected. Without the VE Network, it doesn't know the battery voltage and therefore stops charging.

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