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jpd1009 asked

Smart shunt not sjhowing solar...sort of

I have a smart shunt connected in my camper and need help with a little troubleshooting of readings.

System outline:

2 x 100 amp hour batteries set in parallel.

Shunt connected negative to battery and load side to a distribution point that holds all charges and loads.

For charging I use an Atem DCDC & MPPT combined charger. So there is only one neg going to the load side of the shunt. All positives to the positive terminal via a distribution point.

I have attached 3 images;

1. the one that shows Power 101W is when connected to DC charging source.

2. the one that shows Power 0W is connected to solar panel (in full sun)

3. the one that shows Power -1W is when nothing is connected

The LED's on the DCDC/MPPT unit indicate correctly when either DC or Solar is connected.

My question is around item 2. Why 0W?img-6290.pngimg-6291.pngimg-6294.png

SmartShuntsolar
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img-6291.png (344.2 KiB)
img-6294.png (347.3 KiB)
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Paul B avatar image Paul B commented ·
you may need to test that the panels are putting out amps as you could have a bad connection in the total string setup. this will show open circuit volts


I suggest that you take the PV string Pos and neg wires out of the mppt unit that go to the PV panels and then short them togeather and then with a clamp meter measure the amps that they supply -

in good sun this should be close to the panels spec sheet. figures



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1 Answer
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Can you test/confirm that there is energy coming from the panels, maybe the problem is on that side.

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jpd1009 avatar image jpd1009 commented ·
Hi Matthias, Yes, I have 2 solar panels and tested them with a multimeter. Also, the DCDC/MPPT converter LED lights are behaving correctly for charging.

I am leaving the panels on for a few days to monitor if they are actually charging. If they are not then I would expect to see a natural drop in battery level.

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kevgermany avatar image kevgermany ♦♦ jpd1009 commented ·
You have a voltage drop already. Maybe post your solar charger setting as well as measured panel voltage at the charger.
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jpd1009 avatar image jpd1009 kevgermany ♦♦ commented ·

I have measured the 2 independent solar panels today.

1. A = 22.2, V = 0.9

2. A = 22.8, V = 0.87

So pretty much the same on this very overcast day. The shunt still shows 0 watts and amps.

The strange thing is that I know the battery is charging based on being away last week off grid.

What perplexes me is that there is only one set of charge wires coming from the DCDC /MPPT unit so you cannot wire the solar wrong


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Related Resources

SmartShunt Product Page

SmartShunt Installation Manual

SmartShunt Quick Installation Guide

SmartShunt Datasheet

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