Battery SOC 100% but still charging?

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piet-hein-van-asselen asked Mar 17, '21

Battery SOC 100% but still charging?

Hello

In a solar system i have 2 packs of both 4 exide 330A gel batteries. Together this forms 2 sets of 24 volt batteries.

This setup is charged by solar panels connected to a MPPT 150-60 and a Multiplus compact 12-1600 is connected as well.

The system is monitored by a BMV 700 and this is connected to a color control gx.

Settings for the BMV are:

- Ah 660

- charged voltage 28,4 volt

My question:

Why the BMV tells the battery is 100 percent charged while the voltage is around 26,70-26,85 and still charging around 8 amps??

Shouldnt voltage readout be like around 28 volts and charging amps around at max 0,5 or so?

ThAnks in advance!

Best regards, Piet

battery charging BMV Battery Monitor SOC

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Ulrich answered · Mar 17, 2021 at 10:25 AM

Hi,
the SOC is calculated in a very complex manner. There are complex parameters that need to be set. It took me a couple of tries to get a reliable result.

There are a ton of YouTube videos on the subject at Victron. There you will get a lot of tips for the different battery types. This video helped me a lot: https://www.youtube.com/watch?v=mEN15Z_S4kE

greetings

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Answer 1 · 2021-03-17T10:25:45Z

Stefanie (Victron Energy Staff) answered · Mar 17, 2021 at 10:25 AM

Hi @Piet Hein van Asselen,

no, not really. It depends on your tail current settings in the BMV. Example: if it's set to like 4%, it means 4% of your total capacity. You need to play around with this parameter a bit. But 4% seems to be a good value to start with. With 8A charge current left your battery can be considered fully charged.

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Answer 2 · 2021-03-17T10:29:53Z

seb71 answered · Mar 17, 2021 at 10:29 AM

The charging is not halted if BMV SOC reaches 100%.

Put some screenshots with the all battery setings from BMV.

Screenshots with the MPPT charger settings.

Screenshots with the Multiplus charger setings (if you charge from the grid with it).

Any assistants used? ESS?

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Answer 3 · 2021-03-17T11:13:10Z

piet-hein-van-asselen answered · Mar 17, 2021 at 11:13 AM

Hello all,

Thank you for your quick responses.

By your comments i learned a few things. It seems due to the solar system charging the batteries, i have to keep the charged voltage higher then when charged by a battery charger. This has to do with fluctuating voltage from the MPPT.

I also learned the BMV uses a few settings as Stefanie mentioned.

I will play a bit more later with this when values changed by charging.

I bumped into this video and it has some same onfo as the one i the link from Ulrich.

https://www.victronenergy.com/blog/2017/04/13/instructional-video-how-to-optimise-the-bmv-700-series-sync-parameters/

Thanks for helping out !

Regards, Piet

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