question

Jan avatar image
Jan asked

BMV-712 Smart It's not synchronizing because the charging current is out of range.

The instruction manual states that:

Some lithium battery chargers stop charging when the current drops below a set threshold. The tail current must be set higher in this case.

I have a portable device equipped with a 12V 12Ah (c20) LiFePO4 battery and BMV-712 Smart. The charger, as well as the entire device, is waterproof, so I cannot exchange it.

My issue is that automatic synchronization is not working, the charger completes the charging process at a current of 1,1-1.2 amps, then the green light comes on and it shuts off. Periodically, when the battery voltage drops, it turns on, charges, and then shuts off again.


For BMV-712 Smart to synchronize, three conditions must be met: charged voltage, tail current and charged detection time.

My charged voltage is set to 13.8V (the battery voltage when the charger finishes the charging process is 14.2V).

Tail current is set to 10%, which is 1.2 amps

charged detection time is 1m - this value is too high because the charger finishes its work immediately

The remaining settings are:

1.png


What can I do about this?


BMV Battery Monitor
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1 Answer
pwfarnell avatar image
pwfarnell answered ·

As you have set the tail current to 10% which is the maximum setting according to the manual, the only thing you may be able to change is the detection time, the manual says that this can be set to 0 mins.

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Jan avatar image Jan commented ·

When I set it to 0, it changes to 1 minute. I cannot set it to 0. I don't know why the manual specifies a range from 0.

In this thread, the BMV-712 user also attempted to set it to 0 without success.

https://community.victronenergy.com/questions/137473/charged-detection-time-bmv-712.html

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pwfarnell avatar image pwfarnell Jan commented ·

There does not appear to be any way to get automatic synchronisation.

One workaround would be to double the battery capacity so the tail current is 2.4A but then the SOC would be completely wrong.

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