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johnsg avatar image
johnsg asked

SmartShunt shows decreasing SOC on shore power & battery is fully charged

My 500A SmartShunt shows a dressing SOC even when I'm on shore power. My AC Charger shows me the battery is fully charged and yes there is a small current draw on the DC system as the caravan has been designed to use the DC system for lights and 12V fans but this current draw is more than covered by the solar and AC feed.

The cables to the shunt are correctly connected and I have the latest firmware on the shunt. Attached are pictures to show my settings and the SOC below 100% as well as my AC charger remote display showing fully charged.

Any clues guys and gals? TIA


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SOC
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img-6152.png (239.9 KiB)
tempimage81nmbw.gif (4.0 MiB)
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3 Answers
kevgermany avatar image
kevgermany answered ·

Are there any wires connected to the negative battery terminal, as well as the one that goes to the shunt?

If so move them to the load side of the shunt.

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Alexandra avatar image Alexandra ♦ commented ·
Can we assume there is no solar?

What is your battery chemistry?

How have you programmed the AC charger?

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johnsg avatar image johnsg Alexandra ♦ commented ·
The shunt is correctly cabled. One cable to the battery negative and one cable to the negative bus bar.
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johnsg avatar image johnsg Alexandra ♦ commented ·
Three 120AH lithium batteries connected in parallel. Yes there is solar as well
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delf67 avatar image
delf67 answered ·

The AC charger must be going directly to the battery rather than through the shunt.

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johnsg avatar image johnsg commented ·
Sorry but I don’t think that is correct - everything has to go through the shunt.
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delf67 avatar image delf67 johnsg commented ·
No I meant for this to be happening it must be wired that way, not it should be. Badly worded on my part, sorry.
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pwfarnell avatar image
pwfarnell answered ·

Bear with me here, I know you have said the shunt is wired correct, do you have a negative ground connection to the chassis and if so is this on the load/ system side of the shunt. I ask because we get quite a few RV, boats, vans & caravans with a chassis ground connected directly to the battery negative and you get some current bypassing the shunt, it has to be on the shunt system side. If you do not have this then apologies.

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