question

Sim Wonkdonk avatar image
Sim Wonkdonk asked

Help me work out what's going on with my solar set up (Smartsolar 75/15 MPPT, 180w panel)

Early last year I had a solar panel professionally installed (photonic universe 180w) and a controller (Victron Smartsolar MPPT 75/15).


I didn’t really use my van as much as intended last year, but spent a good chunk of time in it in march this year, I was super impressed the battery was hanging around 13.4 v all the time I checked, and then this summer I got a bit panicky the solar panel wasn’t working because I was only ever reading 12.8v max. This has sent me down an absolute rabbit hole, but two things of note, I’ve since remembered in march I had hookup as I took a fan heater everywhere I stayed, and when I got the controller installed I disabled bluetooth, as someone said it would drain the leisure battery. So the 13.4 reading probably wasn’t accurate.


So after all this panicking I’ve managed to reenable bluetooth on the controller, so can look at trends of charging again, and its showing that when I’ve been using the van its been bulk charging, but when I’ve not been using it and its been on the driveway its been doing nothing. So that sounds like its charging fine, right?


Whats really thrown me is the installer also mentioned that if its a slow blue blink on the mppt its not “working”, and if I put a multimeter on the screw heads where the solar panel is connected to the mppt, I should be getting a constant voltage supply from the panel to the mppt, which is another behaviour I’m not seeing. Does anyone know a bit more about whether this is true? The installer also asked me to send him a screen grab of the app status which I’ve attached, and he said that showed the panel isn’t working.


I’m very confused how it can show all these things suggesting its not working, and have a panel thats providing 0 input on a multimeter but still showing charging trends on dates I've been out and using the van

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MPPT Controllerssmart solar charging behaviour
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1 comment
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Alexandra avatar image Alexandra ♦ commented ·

@Sim Wonkdonk

Installer seems correct the panel is not working very well. Or at least that is what the data is showing right now.

Check connections as the app suggests from the panel to the charge controller. Disconnect the panel and check VOC. Check wiring for damage.

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3 Answers
macca61 avatar image
macca61 answered ·

yes you should be getting various voltages depending on the sunlight but around the 20volt mark , go back to the panel and pull the plugs at the panel check for voltage there, its probably between them and the controller

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kevgermany avatar image
kevgermany answered ·

Do you, by any chance, have alternator charging as well? An Orion, for instance. But what you're seeing in the records could be an intermittent connection between panels and MPPT.

Agree with the others about the panel.

Good forum name. Took me a while to work it out.

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Alexandra avatar image
Alexandra answered ·

@Sim Wonkdonk

A further thought, if it is taking so little energy to raise the battery voltage up, then the battery is dead.

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