question

gagan-ranatunga avatar image
gagan-ranatunga asked

VRM SOC issue

capture.pngcapture2.pngIt doesnt Reach 100%


when-i-change-it-to-95.pngWhen I change the bulk to 95%


capture3.png



capture4.pngSOC is at 89% but the battery is at float

Hi Team,

I have an issue with a system I installed, the SOC is giving weird readings, the setup is 200ah x 4 gel batteries with an easy solar 11 5000 gx. The SOC doesnt reach 100% and when I change the bulk charging up to 95% , the SOC jumps from 85% to 95% can you help me to solve this.

VRMEasySolar All-in-One
capture.png (20.7 KiB)
capture2.png (111.5 KiB)
capture3.png (83.9 KiB)
when-i-change-it-to-95.png (33.6 KiB)
capture4.png (105.2 KiB)
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1 Answer
Alexandra avatar image
Alexandra answered ·

@Gagan Ranatunga

This is mostly because the charging is voltage based with no way of measuring the amps or amp hours to and from the battery. It is worse when it is solar only charging since that will be voltage based as well and the solar provides direct to loads and battery charging. Then the ve bus 'knows' even less about where the power went.

Are the settings also the same on the mppt?

If a shunt is added you will find things will improve in that regard.

In any case if your batteries have reached target voltage and they aren't taking in any more amps then they are charged.

Does it get to 100% when you connect to grid?

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Alexandra avatar image Alexandra ♦ commented ·
The 85% and the 95% you set there is where the inverter will stay in bulk charge. So the jump up is related to the setting change.

What batteries do you have? It is usually only flooded lead acid that have 80% efficiency.


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gagan-ranatunga avatar image gagan-ranatunga commented ·

Hi @Alexandra

Thank you for the reply, the batteries are gel batteries 200Ahx 4, ya and it is the same settings on the charge controller aswell. There is no grid connection as it is completely off the grid and charges only from solar. any idea on how to get to 100% ?

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gagan-ranatunga avatar image gagan-ranatunga gagan-ranatunga commented ·

OPzV12-200.pdf this is the datasheet for the battery

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opzv12-200.pdf (1.5 MiB)
Alexandra avatar image Alexandra ♦ gagan-ranatunga commented ·

Thank you for sharing the datasheet.

Looking at the charge graphs SOC when bulk is finished is more likely to be 80%. But it is at 80% with 50% of the time left to full absorbtion if it started at 80% DOD.

Again the VE bus can't really work out the SOC if it is solar only charging especially if there are loads as well.

I know this from experience and ended up adding a BMV.

On your GX in system set up - system status is it set to use solar charger current to improve SOC?

Do you have balancers on the bank as well? And are you sure that is the temperature compensation value? If you check the datasheet again you will see a different value.


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