question

yvonbell avatar image
yvonbell asked

Soc wrong?

I have a 12 volt 230ah lithium battery. The smart says 100% soc but voltage says 11.7. Verified by multimeter. This doesn’t make sense,no?

SmartShunt
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Alexandra avatar image Alexandra ♦ commented ·

@Yvonbell

No. The SOC is incorrect but then what are your settings on the shunt?

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6 Answers
nickdb avatar image
nickdb answered ·

If the system has not been properly configured it makes perfect sense, and is expected.

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yvonbell avatar image yvonbell commented ·

I’m not gonna Be near the shunt for a week or so. Do you have suggestions?

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pwfarnell avatar image pwfarnell yvonbell commented ·
Post a screenshot of the current settings on the shunt and we will review them and makes suggestions. It is also worth noting how you charge the battery (solar, mains charger), and what absorption voltage you use and typical charging current. Under some situations the shunt can synchronise to 100% before the battery is full.
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yvonbell avatar image
yvonbell answered ·

So this battery was used in a cottage, off grid. I set my magnum inverter charger to lfp battery. Absorb time 1.5 hours..low battery cutout at 11 volts. , my Midnite kid charge controller absorb 14.4 for 15 minutes.float 13.3 low battery cutoff 10.8, reconnect 12.4. img-7148.png
this is what my shunt is showing.


img-7148.png (238.1 KiB)
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kevgermany avatar image kevgermany ♦♦ commented ·
Charged voltage is too low. Set it to just below absorption voltage.

And set both chargers to the battery maker's recommendations. Same on both.


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yvonbell avatar image yvonbell kevgermany ♦♦ commented ·
Thanks. I’ll try that
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yvonbell avatar image yvonbell yvonbell commented ·
So I tried that, I installed the battery at the camp yesterday. When I went today it said 40% soc. Brought the battery at home put the charger on it and it says 100% soc. The multimeter says 13.02. Which is about 40%. Any ideas what’s going on?
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Alexandra avatar image Alexandra ♦ yvonbell commented ·

@Yvonbell

The reason for the 100% when you reconnected the battery is the setting "Battery SOC on reset" rather put that to 'remember last'.... Rather than your current setting of 'Set to 100%'

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yvonbell avatar image yvonbell Alexandra ♦ commented ·

It worked! Thank you!

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Al avatar image
Al answered ·

Might be useful to watch this video:



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yvonbell avatar image yvonbell commented ·

I watched the video. Did everything he suggested as well as what you did. Still show 100% 13.01 volts. I have another battery there, different company. It works fine

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pwfarnell avatar image
pwfarnell answered ·

The other thing you can try is to set the charged voltage to 14.2V, just below your absorption voltage to delay synchronisation to 100% to the last possible point during the charge cycle in case you are getting synchronisation to 100% well before they are charged because you may have low charge current from solar which the shunt misinterprets as the end of charge.

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yvonbell avatar image yvonbell commented ·

I’m thoroughly confused. I have two different batteries, not on any charging device, they are both depleted….. all I want is the state of charge…. Should this shunt not provide this? It says 100% to each battery. I don’t understand this.

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pwfarnell avatar image pwfarnell yvonbell commented ·
The shunt does not base SOC on voltage. It measures the current going into or out of the battery to count the SOC up or down. This can drift due to inaccuracies so when the battery is full it resets to 100%. It determines if the battery is full if the voltage i s above the charged voltage setting and the current is below the tail current setting. This is why we said to put your charged voltage to around 14.2V, just below absorption so you know the battery gets to full voltage before it resets.


Another setting you have is "Battery SOC on reset" and yours is set to "Set to 100%" . This means each time you turn the shunt off or disconnect the battery, when you turn it back on it will start at 100%. Are you turning this on and off a lot because this could be your issue, you can swap this to "Keep SOC" so it remembers what the battery was at or "Clear" so it always starts in an undefined state until it gets the first full charge and synchronisation.


The other potential issue is with the one battery or wiring or fuses, if anything has a high resistance during charging then to the shunt and chargers it will look like it has charged because the voltage has increased but not much charge current is going in. You say your other battery works OK. Next time you charge it look to see the voltage and how much current is going in. Compare the other battery.

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yvonbell avatar image
yvonbell answered ·

So I cleared the soc setting. Then I placed the big battery on charger. Then I placed the smaller battery on charger. Then I took a screenshot of the smaller battery built in blue tooth. The following are the screenshots

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yvonbell avatar image yvonbell commented ·

img-7362.png

100ah aolithium

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img-7362.png (158.4 KiB)
Alexandra avatar image Alexandra ♦ yvonbell commented ·

@Yvonbell

The two dashes means the shunt is not synchronised.

Also switching batteries wont help the situation. It is designed for permanent mounting and battery connection - on one battery bank.

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yvonbell avatar image yvonbell Alexandra ♦ commented ·
So I should click synchronize and it should start working?
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pwfarnell avatar image pwfarnell yvonbell commented ·
Do not click synchronise until the battery is full, but the shunt should synchronise itself anyway. Synchronise means set the SOC to 100% when the battery is known to be full. Notjing to do with charging.
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yvonbell avatar image yvonbell pwfarnell commented ·
Thanks!
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yvonbell avatar image yvonbell commented ·

img-7363.png

Built in blue tooth

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img-7363.png (326.4 KiB)
yvonbell avatar image yvonbell yvonbell commented ·

230ah Litimeimg-7360.png

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img-7360.png (161.7 KiB)
yvonbell avatar image
yvonbell answered ·

I cleared up one thing, I had a negative wire on the negative post where I should have had it in the load side. Now at least I have the current coming in

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Alexandra avatar image Alexandra ♦ commented ·

@Yvonbell

Its always the basics.... That's what the quick install manual is for.

The manual has a section for incorrect readings.


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