question

Tommy avatar image
Tommy asked

Negative DC power, please help!

I asked this question before on another post, but I was not clear in asking the question so I will try again.

When my solar controller is producing more watts than my camper 12v system is using, the watts listed on the battery is incorrect and the DC power goes negative.

Screen shot of correct normal operation. I believe this screen shot proves I have the shunt wired properly.
cerbocorrect.png_____________________________________________________________________
S creen shot showing incorrect data:

Here, the solar is producing 84w, but the battery says it is charging at 137w and DC power is showing -53w. If I had another charger hooked up, I could see this being correct, but I do not. It's like the shunt is wired backwards. The problem only happens, (and always happens) when solar is producing more watts then the camper is consuming. As soon as the solar drops below 53w, the numbers are correct again.

screen-shot-2022-04-07-at-101159-am.png
Details: I have solar panels on the roof of the camper, wired in series
I have two 12v battleborn 100ah in parallel

I have a victron 100/30 mppt controller

I have a victron 712 battery monitor

My camper lights and refrigerator run on 12v

I am NOT connected to shore power, generator is not running, no other chargers hooked up

I do not have an inverter

Chassis battery positive is isolated from house batteries with libim 225; I have ensured the libim doesn't have the batteries connected

I have verified the load side of shunt is wired to negative load, and battery side wired to negative battery terminals

The ground screw on the solar controller is wired to load side of shunt

the positive output of solar controller is connected to the battery bank (with a fuse), neg output connected to load side of shunt

I have verified that the negative wire from the solar panels, is NOT grounded to chassis

In cerbo, "has dc system" is set to ON

Again, The problem only happens, (and always happens) when solar is producing more watts than the camper is consuming.

Thanks,
Tom
battery chargingsmart solar set-up help
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1 Answer
snoobler avatar image
snoobler answered ·

You've been asked multiple times to provide a wiring diagram and/or pictures, yet your response is to cross post and start over.


Not productive.


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