Odd battery protect behavior in lithium mode

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david-ktn asked Jul 30, '20

Odd battery protect behavior in lithium mode

I have a smart BP-65 connected to a mini-bms and victron lion battery. The BP-65 is configured for LION mode through the app. When I unplug the remote connector, simulating loss of +12v from BMS, nothing happens. My understanding is in LION mode it should immediately disconnect the load? If I unplug the ground, the BP says it's shutting down due to low voltage, which again my understanding is in LION mode the voltage settings are ignored?

Any thoughts? I did a reset to default but no change in behavior.

Lithium Battery Battery Protect

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Answer 1 · 2020-07-31T18:38:18Z

david-ktn answered · Jul 31, 2020 at 06:38 PM

As a follow-up, I was able to put a meter on the remote wire coming from the BMS to the BP-65 and I can see the voltage on the trigger wire is +12v (12v system), and when I disconnect the trigger from the BMS the voltage steadily degrades down to something < 1v over a period of about 90 seconds. However the BP doesn't turn off when the remote wire is no longer pulled high, nor after it has degraded to <1v. My next thought was to try and see what happens when its pulled low, or maybe use a resistor so the voltage drops from 12v more quickly. But still weird its not functioning as I would have expected based on the documentation.

Anyone else seen anything similar?

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