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connorgleason avatar image
connorgleason asked

SmartShunt Wiring Question (How to measure loads with ground not connected to "System Minus")?

I just installed a lithium battery bank + DCDC + SmartShunt on my Class A motorhome. I have installed the SmartShunt as instructed, and it measures all loads going through the inverter really well! However, I have an AquaHot hydronic heater that runs off diesel and +12V. The ground for this AquaHot goes straight to the chassis and not the "System Minus". When the AquaHot turns on, I do not see any change in the app to power consumption, so I don't think it's being measured. Any ideas? Thank you!

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Alexandra avatar image
Alexandra answered ·

@connorgleason

Is the shunt the only thing connected to the battery terminal and all negatives after that?

Are you sure the heater is pulling power from the house battery?

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connorgleason avatar image connorgleason commented ·

I have 2x 12V in parallel. The parallel pack has one neg going to the RV chassis and one going to the SmartShunt. The "System Minus" is connected directly my Magnum inverter. So there are not any negatives coming from any load to the batteries directly. Regarding the heater power source - great question. I assumed the +12V was coming from the house batteries because draining your starting batteries to run an AquaHot would not seem like a good idea :) In any case, I will confirm. However, assuming the AquaHot is getting +12V direct from the battery bank and the ground being bolted direct to the chassis...would it be measured?? Thanks for your help.

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pwfarnell avatar image pwfarnell connorgleason commented ·
The negative to the chassis needs to be moved from the battery to the system side of the shunt. Then any current flowing through the chassis will go back through the shunt. Most common mistake in RV wiring.
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