question

thompsondr1 avatar image
thompsondr1 asked

Charger moving to Float and not moving back

I will preface by apologizing for not being an electrical expert...but I'm running into a few issues. I have a Victron BMV 712, a Victron MPPT charge controller 100/30, 300 watts of solar and 200ah Battleborn batteries (all fairly new). My batteries were charging up to around 85% in Bulk then spending some time in Absorbtion and finishing in Float to 100%. Now they are switching to Float at around 80% and will not switch back to Absorbtion or Bulk for the remainder of that day. I have tested this by waiting until it goes to Float and turning on my appliances and running it down to 50% (all the while the MPPT stays in Float). The next day it cranks right back up in Bulk and goes up until about 80%. I am using the app and (think I have) configured my charge controller and BMV according to Victron instructions. What could be happening here and/or what information would need to hazard some guesses? Thanks!

battery charging
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4 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @thompsondr1

Can you show a screenshot of your charging settings?

if you select 'expert mode' there is a setting for re-bulk voltage.

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thompsondr1 answered ·

Here are pictures of the Battery screen from the MPPT and the BMV. Let me know if there was something else that would help. Thanks!


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thompsondr1 answered ·

Of course after writing this yesterday it has spent the entire (super sunny) day on Bulk, even after the battery was 100% full hours ago. Maybe I’m just focusing on the wrong thing and the % full actually has no connection/correlation with what charge stage it should be in(?)

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Hi @thompsondr1

voltage / current is your proof, if your battery monitor is not setup correctly, or connected properly, it can be wrong :)

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thompsondr1 answered ·

Any chance you could be a little more specific about what I should check and what I should expect to see? And I do have a voltimeter.

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about the BMV settings: charged voltage should be (close to) absorption voltage, so 13,2V is way too low and can cause the unit to sync to 100% too early

https://www.youtube.com/watch?v=4ReljfO3k6M


about charging: look at the voltage where it goes to absorption / float, does that correspond with the settings?

PS. 14.6V seems very high for a LiFePO4 battery, what is the minimum charging voltage according to the manufacturer?

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