no volts showing

IreneIrene Registered Users Posts: 2
I hope someone can help me. I have put up 4 unisolar 136 watt flexible panels in series. I'm told they are 24Volt panels. I tested them at the end of the 4Y connector, and it is showing 43 volts. I'm thinking this is VOC. When I connect them to the cable that runs to the charge controller, there is 0 volts reading at the end of this cable. It's the same size cable that is on the panels. So nothing is reading to the charge controller. I tried an amp test, using 1 12 volt batteries in series, and I get 0 reading for amps there. I DON'T KNOW WHAT THE DEAL COULD BE. I ran a continuity test on the cable running from the 4Y top the charge controller, and there is continuity. PLEASE I need advice.

Comments

  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    Well lets get our nomenclature the same...

    Series would be; + panel - + panel - + panel - + panel -

    Normally 'Y' connectors connect panel in parallel connecting all the positives and negatives, so is your in parallel?

    If in series you should see the voc increase with each additional panel in series, I think the Unisolar 136 watt panel has a VOC of around 46 volts so I think you are in parallel.

    so once you combine the panels you see voltage at the ends one positive end and one negative end?

    Then you run a wire to your controller, can you take this end and still measure voltage from the previous point with each end? This should be straight forward, connect one long wire and check voltage, if you know it's good use the new extended end to check voltage once you add the wire extending the other end. In this manner you can see which wire has lost continuity. If they both have voltage at the end of the extended wire, we move to the charge controller.

    What charge controller are you using? Did you read on how your charge controller likes to be hooked up? If it sets the voltage, not you, it will likely want the battery connected first. If it's a PWM type controller you may have too much voltage for a 12 volt battery! SO lets see where you stand and we can look at what needs to be done from here.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    If you had a battery connected and tested for amps you may well have fried your meter! Most meters are only good to 8 or 10 amps. did you switch where your meter cables connect to the meter? Voltage should be fine for tracking down problems and even if the current feature is fried, you may be able to check for voltage still.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • IreneIrene Registered Users Posts: 2
    The panels are in parallel. 1 Y connector for all the positives, 1 for all the negatives. I can get a voltage reading when I test at the end of these Y connectors. Then I run a 15 foot cable, made of the same wires that are the leads running off each panel...they look to be about 10Guage, but specifically for solar. If I test for voltage at the end of the 15 foot cable, I get nothing. So I disconnected the `15 foot cables, and checked for continuity. That checked out fine. so if the 15 foot cables ore good, why don't I get a voltage reading there? I have a tracer 4210RN MPPT charge controller. The PV light does not come on, but the battery light does. I ran down the batteries, and they are currently at 11.8v, so that isn't the problem. Do I need to pitch the 15 foot cables and go to like 6 GA cable instead? If so, how do I connect 6 guage to the solar panels, since the panels terminate with MC3 connectors?
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    Sounds like the connectors are different, odd situation, did you try connecting one to one side and check for voltage, then the other to see if you can narrow it down to a single cable?.

    I use to have MC3 connectors, and I don't recall having seen or heard of any other cable connectors like them, so I'd discount a wrong type of connector, though perhaps there are MC3 with wider connectors for thicker wires, but then the opposite mating cable wouldn't mate. Maybe some where someone stuck too large a wire into a connector end, or stuck in a nail or something to use as a test and spread the connector.

    Yes you need to charge those batteries before you use them any more! If the array is your only source of charging, I would try my best to trouble shoot the wiring, and if I couldn't figure it out, go ahead and butcher the end, Unisolar filed for bankruptcy back in 2012 so unless the supplier is warrantying these, you won't lose much.

    I have not mentioned that 4 panels in parallel should have fuses or breakers for each panel. If you choose to butcher(remove the connectors) you could use a combiner box to join the wires and run your single wire back to the charge controller.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • muliamulia Solar Expert Posts: 62 ✭✭✭✭
    Irene wrote: »
    The panels are in parallel. 1 Y connector for all the positives, 1 for all the negatives. I can get a voltage reading when I test at the end of these Y connectors. Then I run a 15 foot cable, made of the same wires that are the leads running off each panel...they look to be about 10Guage, but specifically for solar. If I test for voltage at the end of the 15 foot cable, I get nothing. So I disconnected the `15 foot cables, and checked for continuity. That checked out fine. so if the 15 foot cables ore good, why don't I get a voltage reading there? I have a tracer 4210RN MPPT charge controller. The PV light does not come on, but the battery light does. I ran down the batteries, and they are currently at 11.8v, so that isn't the problem. Do I need to pitch the 15 foot cables and go to like 6 GA cable instead? If so, how do I connect 6 guage to the solar panels, since the panels terminate with MC3 connectors?


    If you connect them parallel, they should end up with 24V, not 43V in your first post.

    10AWG should be able to handle them (up to 30A according to NEC).

    I wonder 15foot cable is connected to these panels directly (hard-wired) or using MC3 connector? If it's using connector, you should try to change the connector or try to 'hardwire' it.

    Happened to me before, the connector failed/loose therefore no voltage/current shown, changed it using another new MC4 connector and it's good to go.

    If you can find new MC3 connector, it worth to try changing 15 foot cables connector, then connect the array and measure it.
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    I agree with you Mulia, in that she may have to replace the connectors.

    As I pointed out before these panel have a VOC of 46 volts so 43 volts is not out of line for the panels in parallel.

    I hope she hasn't given up on us, maybe she got things working, inquiring minds want to know!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • muliamulia Solar Expert Posts: 62 ✭✭✭✭
    Most problems seems so big actually can't be fixed with little troubleshooting. Like changing the connector.

    I hope so. I think she has it working by now.
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