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Vilmas avatar image
Vilmas asked

SmartShunt 500A SOC issue

Hello
Got a problem with my 500A shunt.
The SOC reading increasing and increasing. Every week I have to reduce the SOC by about 5%.
Looks like IN and OUT current readings aren't equal.
VRM portal shows all the time the battery gets charged from not existing external source. I did zero calibration, and I changed the parameters... Only one thing is a bit helping. Connecting to the battery charger. Setting about 30w and doing the Zero calibrating.screenshot-2024-01-18-at-140448.pngscreenshot-2024-01-18-at-140515.png

It is my Shunt parameters and VRM


SmartShunt
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3 Answers
klim8skeptic avatar image
klim8skeptic answered ·

@Vilmas Batteries are not 100% efficient during their charging cycle. You have set the charging efficiency as 100%, as such your Soc will drift a bit each day.

Perhaps you could share your battery details, and some info about your installation so some guidance could be given.

Might be worth watching this BMV youtube tutorial.

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Vilmas avatar image Vilmas commented ·

Hi. I know the batery aren't 100% efficient.In my case the battery is 110% efficiency. As I said before. Every week i need drop SOC by 5-10%. I'd believe in 6 months or so my flat battery would have the 100% of SOC.. My system is simple offgrid islan. Battery 2x 234Ah s14 lion.Anything else on vrm picture above. P.S. No grid.

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klim8skeptic avatar image klim8skeptic ♦ Vilmas commented ·

@Vilmas In my case the battery is 110% efficiency

If you lower the charge efficiency a bit that will bring that back to parity.

Tesla batteries have a charge efficiency of ~94%, Leaf batteries ~ 87.5% (??)

What sort of Lion cells do you have? Somebody might know setting suitable for them.

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Vilmas avatar image
Vilmas answered ·

If I set less than 100 it would be worst. I need to get above 100%. It is not possible, even in real life. Think the problem is the current reading. it has to read both ways (charge and discharge) the same, but it doesn't in my opinion. I noticed it in the wintertime as the battery never goes to 100% and doesn't reset.
Victron must set the bottom reset in this case. I have to reset it manually The reset has to be flexible to set as 95-100% and 0-10%.

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JohnC avatar image
JohnC answered ·

@Vilmas

By setting your Charge Efficiency to 100% you're telling the Shunt to use 100% of it's measured current to calculate SOC, when less than that is actually making it to the batteries. So it will always show higher than the battery actually is. As you've described..

Compensating with the Zero calibration isn't in the manual. And some of your other settings will need work too. But sort this one first.

@klim8skeptic knows his stuff, he's trying to help you..

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Vilmas avatar image Vilmas commented ·

Hi. Could you point me what settings I could adjust except smart shunt settings? I cant set above 100% and lover as 1 peuker. Thanks

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JohnC avatar image JohnC ♦ Vilmas commented ·
@Vilmas

Do a Zero Current Calibration (without the bias) and start by setting your Charge Efficiency to 90-95%, then work from there. We still don't know what your batteries are.

Best grab the manual off the Victron website and keep reading it until you understand what each of the settings actually do.

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