BMV712 jumps from ~75% to 100% and continues to show high charge rate for several hours

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brent-carroll asked Oct 6, '20

BMV712 jumps from ~75% to 100% and continues to show high charge rate for several hours

I've seen other responses to this question that did not help me solve this - like, read the manual. I did, followed the setup, and I am still stymied. I have a 960W PV, Quattro 5K, 2 100/50 MPPTs, 3 200Ah Smart Lithium Batteries, and the BMV712. It's all brand new and works perfectly except for this one thing. After night time discharge down to ~60%, normal charging seems to occur throughout the day. But, in watching the BMV (and looking at history on VRM, it jumps from ~75% to 100% SOC, and then continues to consume 600+ watts of solar for several hours. I've tried the manual zero current calibration, and once I saw current drop and and trickle into the batteries mid-afternoon (assuming it was close to 100%), tried to manually sync the SOC. But, it continues to do this even after. What am I missing? Any help would be appreciated.

BMV Battery Monitor

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Answer 1 · 2020-10-07T01:30:48Z

Vance Mitchell answered · Oct 07, 2020 at 01:30 AM

Can you share a screenshot of your BMV settings?

I suspect that the solar is dropping below your tail current for a period, so either lowering your tail current or increasing the charged detection time might solve your issue.

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Answer 2 · 2020-10-10T12:29:48Z

brent-carroll answered · Oct 10, 2020 at 12:29 PM

Hi there,

So, in consulting with my Victron rep, they suggested the following settings, which has been working for a few days now:

14V Charged Voltage

2% Tail Current

1 minute charge detection time

Discharge Floor Set to 0

Puekart Exp. 1.05

Charge Efficiency 99%

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Answer 3 · 2020-10-10T16:14:35Z

spirou answered · Oct 10, 2020 at 04:14 PM

BMV is just a counter that does calculations based on parameters you set. If those are wrong then any %SOC display is near useless. But people still think that it is something more than an estimate. It certainly has no influence whatsoever on any charging source even when networked together beyond sharing voltage (and temp?) measurements.

Consult the manuals, experiment with parameters and maybe you will come up with something that is close enough. Personally, I hardly ever look at percentage. Voltage, amps and amp hours drawn are all that you need to see what is going on.

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