question

hudelrob avatar image
hudelrob asked

Smart Shunt Negative Current

I have 2 X 200amp lithium batters wired in parallel. 20220503-101344.jpg

When connected to shore power I see a constant -2.88amps and -43W. I turn on some fans and other electrical items and I see the -amps/w increase to a larger -number which would be expected.


I then turn everything off and I see positive amps/watts until my voltage returns to 14.6 at which point it immediately returns to -2.88amps/-43w.

When I disconnect shore-power I see very low -.3 amps and very low W until a small LED light goes out in the hallway of my RV and everything goes to Zero. This seems to be what I would expect to see.

I need help understanding why on shore power and a fully charged battery why I am seeing -2.88amps and -43W which seems odd to me. I can only assume something in the RV is pulling power.

Thoughts or suggestion?




SmartShunt
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1 Answer
snoobler avatar image
snoobler answered ·
Suggestion:


Disconnect everything from the system side of the shunt and do a zero current calibration in the app.


Get a clamp DC ammeter and confirm the values.


I suspect your converter may float at around 13.2-13.6V - below LFP resting fully charge values, so rather than the AC-DC converter providing power, the system is drawing on the higher voltage battery.


See if you observe the same behavior at notably lower states of charge.


I don't understand the specifics, but when I my motorhome is on shore power, my DC master disconnect doesn't work, so it may force certain systems to be on.

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hudelrob avatar image hudelrob commented ·
Thank you Snoobler that appears to have done the trick.
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