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raymiller asked

BMV 712 not reseting SOC to 100% even after MPPT 15/75 has reached fully 100% SOC

I've had this issue for a while and seems to be that the MPPT 15/75 is not spending enough time at the Absorbtion State even though I've trying to set it for a longer period. The overnight discharge is about 16%. As you can see by the graph it is reset on the second Absorbtion state for the solar day on November 14.

On day 14th November the BMV 712 resets the SOC to 100% on the second Absorbtion state but does not on all other occasions the battery voltage reaches 28.4V.

My system is 24V and a 140AH Lithium-ion Phosphate battery. I've set up the BMV712 as per the manual

So it would seem to me the MPPT 15/75 Absortion state time is not matched with the BMV 712.

Some guidance in the various manuals for how to successfully achieve a better co-operation between the two devices would be appreciated.

screen-shot-2018-11-16-at-83759-am.png(105.0 kB)

MPPT ControllersBMV Battery Monitor
screen-shot-2018-11-16-at-83759-am.png (102.6 KiB)
mppt1575.png (87.3 KiB)
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Michael Connolly avatar image Michael Connolly commented ·

How did you get these graphs? Thanks

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raymiller answered ·

A further graph showing the longer time in Absorption State on 14th November when the BVM 712 reset the SOC to 100%. The time was possibly longer due to the lower solar availability with the MPPT dropping back to the Bulk charge state then achieving the second Absorption state, holding the voltage longer to trigger the required for BVM 712 SOC reset.


mpptnov14.png (82.2 KiB)
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raymiller avatar image raymiller commented ·

The first Absorption state is usually about 3 minutes with the second Absorption state was 12 minutes.

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raymiller answered ·

Found the other posts under:

Blue Solar MPPT leaves absorption too early

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