question

Yoni Nijman avatar image
Yoni Nijman asked

SOC synchronisation BMV 700

For some reason the SOC calibration isn't what it should be.

I've seen a video on YouTube to adjust settings for solar charging charged voltage 0.3v under absorption voltage in normal operation it should be under float voltage

But when my 75 15 mppt is in end of absorption it resets it's state of charge.

Mppt keeps charging for a few more hours with 4 amps that means the reading is not close to accurate.

BMV and Smart Solar both Bluetooth connected also with a battery smart, if the mppt and the BMW could talk it could reset it's state of charge when it hits float charge.


Any settings to change to get it as close as accurate?


Thanks Yoni


BMV Battery MonitorSOCsmart solar set-up help
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boekel avatar image boekel ♦ commented ·

this can be difficult to get exactly right with small solar chargers in the system, but it can be done with some tweaking.

For a start, please tell us what kind of batteries you use and if there are any other components in the system.

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Yoni Nijman avatar image Yoni Nijman boekel ♦ commented ·

Hi,

I'm using 2 PBQ cyclic AGM batteries in series 250ah C10 266ah C20

Solar panels 2x200wp parallel

C20 value is programmed to BMV.

Absorption voltage is set at 29.00V float is set to 27.50V this is minimum requirements from manufacturer.

Charged voltage in BMV is set to 28.7V (as stated in victron solar setup video) and tail current down to 2% maybe I even have to lower I think

I think the problem is the low charging current that sets of a synchronisation.

Communication between BMV and Smart Solar would almost completely solve this problem.


Thank for your answer and waiting for your feedback!



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boekel avatar image boekel ♦ Yoni Nijman commented ·

I'd extend the 'charge detection time'

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Yoni Nijman avatar image Yoni Nijman boekel ♦ commented ·

I extended the detection time,.
will take some time to see if it worked holidays are over for now

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1 Answer
Mark avatar image
Mark answered ·

I assume that you have correctly entered the battery C20 capacity in the BMV?

If this is already correct, then based on what your saying I would probably try reducing the tail current % slightly next.

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Yoni Nijman avatar image Yoni Nijman commented ·

I commented above this.

C20 is dialed in but it make sense to lower the tail current think I'll go for 1 or 1.5 percent.

I have a look if this works better but I need some sun to test :)


Thank you for your reply




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