ROLAND CHUNG avatar image

Truck camper - MPPT 75/15 Smart Solar Blue LED slow flashing - But PV leads show 33.09V

Brand new truck camper with factory solar. Solar has never worked. Blue led is slow flashing. PV leads shows 33.09V. Battery leads show 11.65 V. Fuses are good.

Loaded Victron Connect on an android tablet - it updated and connected, but showed no activity. Read about a possible issue with android v5, so loaded app on latest android phone (Note9) with same results. Shows app and connects to device (controller) but shows no activity.

There is a red + lead and a white - lead coming from panels to a utility area under the step up to the camper overhang. When I test those leads, they show 33.09 V (subject to change) on a multitestor.

The red and white leads from the battery shows 11.65 V (subject to change). The + lead shows 33.09 when tested to the - lug on the battery box. The - lead shows continuity when tested to the lug on the battery box.

I've checked the battery terminal connections and they are tight and show 11.65 V on the terminals and on the battery box lugs.

Here's something strange to me. As soon as I connect the other end of the fuse holder into the + terminal of the controller and insert the fuse, the - and + terminals of the PV connection read .850 or less (subject to change). I've checked the terminal on the line side of the fuse holder, re-did the connection between the red lead from the solar panel to the fuse holder, inserted the fuse and checked the lead on the load side of the fuse holder and everything looks good and tests good. But when the pv leads are connected, the terminals show .850 - even when I touch the wires where they insert into the controller, they show .850.

I'm new to solar, but I am wondering if maybe there is a compromised wire running from the roof mounted solar panels. Maybe a nicked wire that only has a few strands of conductor intact. That would be enough for my multi testor to register the 33.09 V but maybe when connected to the controller, the higher demand (to run the controller and feed the batteries) exceeds what the (suspected) few strands can pass along.

The camper manufacturer thought it might be a bad controller and sent me a new one, but it has had the same results as the original.

Another thing that I thought is that maybe there is some activity going on and that the .850 v is a trickle charge occuring and that the Victron Connect app is just not working properly. But the slow flash of the blue led and lack of activity on the other leds would be too much of a coincidence.

Please help.

MPPT Controllers
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3 Answers
Paul B avatar image
Paul B answered ·

could you please send us a screen picture when the victron Connect app is connected to the Smart Solar unit.

I would like to see the summary screen, and under settings the Battery screen.

Some other tests you could do is take the PV leads off the charger and put a amp meter between them, this should show the ratted current coming from the panels, if this is non existent then look for a bad wiring connection somewhere in the wiring to the panels.

You could also check that connection under the steps and put a amp meter across that as well

The panel ratings should be on a label on the back of the panels

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ROLAND CHUNG avatar image ROLAND CHUNG commented ·

Thanks PaulB, If the Christyler fix doesn't work, then I will start on your suggestions.

Edit- I tried reversing the leads into the controller and that fixed it. I will go uptop to redo the mc4 connectors so that the wire colors from there will still be correct. Wait till I let the manufacturer know.

If it is okay, I will still try to send some screen shots of the Victron Connect App for you to review my settings. You might be able to catch something like a setting too high for my battery set up. Thanks again for your help!

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christyler avatar image
christyler answered ·

Are you 100% sure you are the polarity of the PV wires correct, if not try swapping them around temporary. You won't damage anything. If it starts working they were wrong. The fact that you have voltage on the PV wires tells us the panels and wireing are working, I suspect they are just wired the wrong way round

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ROLAND CHUNG avatar image ROLAND CHUNG commented ·

Thank you Chris, sorry for the delay - work stuff. I will try this first.

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ROLAND CHUNG avatar image
ROLAND CHUNG answered ·

Okay Paul and Chris,

Last week, I was able to get the solar controller to read the panel information and basically work. At first, I was happy to see about 75 to 80 watts. The camper is parked on the side of the house and is not using any electricity except for what may be lost by some electrical vampires (tv and entertainment system).

So, when I looked into the solar option for the camper, it turns out to be a 160 watt solar panel system. I'm only showing about 23-35 watts (31.59v / 0.7amps) everytime that I look at Victron Connect. When I look at the history, it shows 75 to 80 watts - being new to solar, I'm not exactly sure what I am looking at, but it seems like I'm not getting close to the 160 watts that I'm supposed to be getting.

My question - is it possible or likely that since the solar panels were connected to the controller with reversed wires since the production date (I pressume), the output of the panels might be compromised? I know that I have had the camper for over 3 months and it is likely that the camper was manufactured months before I got it.

I'm just asking the community as I would like to have some confidence if I need to have the manufacturer provide some warranty service to replace the solar panel.

Also, the manufacturer doesn't really have a reliable service partner in my area. Aside from removing the semiflexible panel from the curved area of the roof, I feel pretty comfortable swapping out the panel if necessary. I would just need to consult this forum for advice on removing the panel without damaging the aluminum roofing.

Please let me know what you think.



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