question

Timothy Bryan avatar image
Timothy Bryan asked

BMV712 Settings with solar

I've just installed the BMV712.

It currently monitors a Lead Crystal 110Ah battery.

Bulk 14.7

Absorption 14.7

Float 13.6

I also run an 80w solar panel through a CTEK D250SA.

I have the 712 at settings:

Charged Voltage: 14.5

Tail Current: 2%

Efficiency Factor: 97%

Puekert: 1.25

Low SOC Relay: 50% 50%

It appears to always show 100% SOC even when the voltage has dropped after a night of accessories running off it.

The settings weren't initially setup like this. Do I need to charge fully and resync? Or is there a settings issue.

BMV Battery MonitorSolar Panel
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2 Answers
JohnC avatar image
JohnC answered ·

Hi Tim. First port of call would be to check your shunt wiring. A pleasant explanation: https://www.victronenergy.com/blog/2017/03/31/instructional-video-how-to-connect-the-bmv-700-battery-monitor/

Check that and come back.


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Timothy Bryan avatar image Timothy Bryan commented ·

@JohnC

Shunt wiring is perfect. I should probably correct myself, it hasn't always shown 100%, at one stage it went down to say 98% but the battery was definitely below 98%.

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JohnC avatar image
JohnC answered ·

Ok. It does help telling us that you've seen it at 98%, so it's likely just in your settings. The two main ones..

Peukert 1.25 may be in the ballpark, so leave that for now.

Efficiency 97%. What that's saying is the BMV is calculating it's % on highly efficient batts (in vs out) and overestimating what's left. Try dropping it to 90% to see what happens.

If you 'overshoot' doing this, your SOC will read too low, so you've gotta home-in on it.

Setting these things up correctly isn't for the impatient, so take your time. Understanding what you're doing with these settings is important too.

https://www.victronenergy.com/upload/documents/Manual-BMV-700-700H-702-712-EN-NL-FR-DE-ES-SE-PT-IT.pdf

Good luck.


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