Fitting solar from scratch

Discussion in 'Mech Tech' started by 1973daisey, Jun 22, 2017.

  1. This is mine, fully charged battery fridge just turned on and an overcast day

    Panel voltage
    Current produced
    Battery voltage under load from fridge
    Cloudy sky

    2x50watt panels on roof[​IMG][​IMG][​IMG][​IMG]
  2. As I’ve just been out taking the photos and readings requested by the Photonic Universe engineer to check out the condition of my 100w panel, I might as well post them on here:
    It was 11am, cloudy sky, no sun, not raining.

    Voltage direct from panel:

    What the controller says:

    Short circuit current off panel:

    What the controller says:

    Current to battery (battery voltage is 12.6v at the moment)

    Panel fitted on roof (air spaces underneath provided by roof ridges)

    If it looks like I've taken any of these reading wrongly, please please do say, as the workings of ampage on sophisticated multimeters these days really is beyond me.
  3. The panel can’t produce 33.1 amps. In theory a 100w panel at 19v would produce 5.26amp.
  4. Agreed! But I think it's reading milliamps?
  5. If mine are anything to go by that’s about right. :) Am I helping?
    scrooge95 likes this.
  6. @77 Westy @scrooge95 so do you both have the same panels but different controllers and getting the same problem?
  7. Different panels too I think. Mine is Photonic Universe.
    To be honest, I wasn't thinking my panel was the problem (I'd assumed it was the controller as there appeared to be voltage and current coming off the panel), but maybe it is? Help!!
    Last edited: Oct 13, 2018
  8. I have two 100w Eco Worthy panels and a 20amp Eco Worthy MPPT controller.
    IMG_5371 (Large).JPG
  9. I'm off camping tonight so just plugged the cool box in its showing 13.1V and 1.09A. It's cloudy outside, with the sun barely breaking through. I wish I could help you more. You definitely got the positive from the panel wired up to the positive on the controller, there's not much else to consider?

    Edit: Just been out again, battery has dropped to 12.9V and now showing 1.9A. Given the weather that seems OK to me.
    Last edited: Oct 13, 2018
    pkrboo, Lasty and scrooge95 like this.
  10. The scale you have the meter set to is 200milliAmps, that means the panel is producing 0.033 Amps when in short circuit.
    77 Westy and scrooge95 like this.
  11. Thank you.
    I'm not sure that's very much is it? Hardly setting the solar world on fire :( I suppose it was cloudy though, but...
    77 Westy likes this.
  12. Yep, not a lot is it?

    What was you engineer expecting?

    I edited the post while you were answering so it now says 0.033Amps, so we're dealing with the same units. In my experience that would nicely illuminate a 5mm LED, but buggar all else.
    Valveandy and 77 Westy like this.
  13. I am no panel expert, but going on what @mikedjames said in his recent post, he reckoned you should be getting 5 Amp short circuit (I assume that's on a sunny day).

    You're getting less than 150 times less that Mike's sunny day short circuit figure.
    77 Westy likes this.
  14. I'm not sure what the Photonic Universe engineer was expecting, probably a bit more than this though! I emailed him the photos this morning, so I guess he will pick that up on Monday and reply with a few more questions.
    I assumed controller failure, but maybe it's not looking good for the panel.
    The controller was bought for me as a Christmas present; the panel I bought myself in February. The system was set up and installed in April / May this year. If something has failed, I would hope for a bit of recompense from the vendor as I'm not sure I've done anything wrong - and it was working in July.
    77 Westy likes this.
  15. I think I know what is wrong but I don’t know why.

    I initially thought the controller was faulty but after measuring the open circuit voltage and short circuit amps it seems that both panels produce very little. Why is still a mystery, a faulty batch of panels is unlikely as they were manufactured several months apart and although I can find a few others with failed panels Eco Worth must sell thousands of them so the failure rate is low. And when they fail it is always after more than a year of use and mine have been on the bus for less than 5 months with much less than that of actual use and I don’t think they worked from the first day.

    So why are both mine so poor, what makes them fail, if it had been just one panel I’d put it down to bad luck, but both of them? Installation is straightforward and the wiring simple but I only tested the open circuit voltage of the panels before I installed them, I didn’t measure the short circuit current. Lesson learned but if/when I replace the panels how do I stop them failing when I don’t know what caused them to fail in the first place?
  16. The only gotcha I can see, having had another look at your photos, is that you plugged into the mA socket and not the 10Amp socket on the meter, but I assume you got no reading when trying the 10Amp socket?

    I'm afraid if those measurement are correct, those panels are doing nothing much useful, but as you say... the big question is....Why not?
  17. Yep 33.1 milliamps
  18. Plugged into milliamps socket is ok, if it read more than 200 mA then it would have shown as OL or overload. And scale would need to have been changed or moved over to ten amp socket.
    Last edited: Oct 13, 2018
  19. I would agree. I don't know what to expect from a panel at short, so starting on the 10 Amps scale would be the safe thing to do. Then again I doubt 33mA would even register on the 10A scale. This doesn't seem at lot of power from a 100 watt panel. If the panel was loaded down to produce 12v, then 100/12 gives a hypothetical 8 and a bit
  20. Yeah, I did start off with the 10A scale, but as it read a bit fat nothing, I switched down.
    pkrboo likes this.

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