Hello and anyone feel like helping me troubleshoot a new system?

unyalli
unyalli Solar Expert Posts: 121 ✭✭
Hello folks, new to solar but not electronics and something is not right.

With the source side of my Doc Wattson connected to the panel and nothing on the load side it's reading Voc right? (No load voltage aka open circuit voltage). Mine seems to, it's at 21 volts around 0.1 amps fluctuating.

If this is true and I then connect the load side to the controller shouldn't this voltage drop to around 17-18? It doesn't, pretty much no change in reading. The controller shows green indicators and over time actually charges the battery slooowly. After three days of moving the panel to follow the sun directly my at rest battery voltage is 13.2 up from 12.6 where I started this expirement.

Everything is brand new. All connections are solid with a new ratcheting type crimping tool and marine grade heatshrink crimp connectors.
Solarland 90watt 12v panel. Vmp 17v Voc 21v 5.2amp at Vmp.
Morningstar Sunsaver MPPT15L controller.

Thanks, Jeff

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Welcome to the forum Jeff.

    Here's the question; what is the output of the charge controller connected to?
    If the answer is nothing or a fully charged battery then there is essentially no load on the panel and so the Voltage will still be very high.

    You can check the panel's Isc to see if it is producing as it should. You can also check the output of the charge controller to the battery to see if any current is flowing there. What size is the battery? The 5 Amps that one panel is capable of is not much, so if the battery is greater than about 50 Amp hours it probably would charge very slowly.
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    Welcome to the forum Jeff. Thank you and thanks for responding.

    Here's the question; what is the output of the charge controller connected to? As stated a somewhat discharged battery at 12.6 volts. This is a group 24 rv/marine battery that came with the camper. It's not a year old.
    If the answer is nothing or a fully charged battery then there is essentially no load on the panel and so the Voltage will still be very high.

    You can check the panel's Isc to see if it is producing as it should. Ok, ISC, will have to see what that is and how to check it, thanks. You can also check the output of the charge controller to the battery to see if any current is flowing there. I did with a craftsman clamp on dc amp meter and it was about .07 amps higher. If I had 0.12 amps at 20 volts into the controller I had around 0.19 amps at 14.8 volts to the battery. What size is the battery? Group 24. The 5 Amps that one panel is capable of is not much, so if the battery is greater than about 50 Amp hours it probably would charge very slowly.


    It does not like me answering within the quote so I have to blather on here.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    unyalli wrote: »
    It does not like me answering within the quote so I have to blather on here.

    That little trick takes a lot of hand-written HTML. :p

    Another thing to try; bypass the charge controller completely and measure the current from the panel directly to the battery.
    Note that as you change the panel angle its current will change (panels are a current source). If it's not square-on to the bright sun you won't get full output.

    Isc is the short-circuit current of the panel. Full sun, straight on, panel leads connected together. This will tell if your panel is putting out its potential.

    Those batteries are usually around 90 Amp hours, so 5 Amps can charge it but it will be slow. There really isn't much need for an MPPT controller on this, but if it's what you have you use it! :D
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Ok, Isc = Current ( amps or I) short circuit. So I have a volt/amp meter that will allow 10amps in series. I connect positive lead to solar panel positive and likewise for negative then place panel in direct sunlight. I think I remember this spec (and I'll check first) as 5.9 amps.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    unyalli wrote: »
    Ok, Isc = Current ( amps or I) short circuit. So I have a volt/amp meter that will allow 10amps in series. I connect positive lead to solar panel positive and likewise for negative then place panel in direct sunlight. I think I remember this spec (and I'll check first) as 5.9 amps.

    Sounds about right. Now as the voltage on the panel is permitted to rise, the current will decrease, and that's normal. You should get at least 4 amps charging your battery when the panel is under full sun around or near noon time, and facing the sun. Any shadow on the panel will DRASTICALLY cut the panel output. The cells are in series, and like the old Christmas tree lights, if one goes out, all the ones in that string go out (stop producing). So if only one cell is in shadow, it will kill the output of the complete string of which it's a part. Your panel may have two strings.
    Sometimes it's the simplest things we overlook :D
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    unyalli wrote: »
    I connect positive lead to solar panel positive and likewise for negative then place panel in direct sunlight. I think I remember this spec (and I'll check first) as 5.9 amps.
    If you are using the Doc Wattson to measure Isc, you must short out the 'Load' side of the Doc Wattson (disconnect everything else, especially the battery, from the Load side of Doc Wattson). The docwattson can easily handle the current of one panel.
    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Checking Isc at lunch today. I have a multimeter capable of 10 amps in-line through put. Thanks all for the tips. panel will be in direct sun angled straight at the sun with no shading of any kind. Supposed to be another clear day and close to 60. I'm in Cheyenne Wyoming so sun is around 35 degrees right now at highest point.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    If you are going to be working with DC power systems a fair amount, a DC Current Clamp Meter (such as this one) is a real handy tool. You do not have to disconnect any wiring, just clip the clamp around the wire you want to know the current. Much safer and no chances of shock or damaging the meter with too much current or acidental dead shorts.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    BB. wrote: »
    If you are going to be working with DC power systems a fair amount, a DC Current Clamp Meter (such as this one)-Bill

    That's one of the meters I have. Yes, could short the panel with a jumper and read current with this meter. This is the meter I used to determine what if any current was going to the battery. Thanks
  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    unyalli wrote: »
    Checking Isc at lunch today. I have a multimeter capable of 10 amps in-line through put. Thanks all for the tips. panel will be in direct sun angled straight at the sun with no shading of any kind. Supposed to be another clear day and close to 60. I'm in Cheyenne Wyoming so sun is around 35 degrees right now at highest point.

    I also have a 10A multi meter, the cheapest one sold by Harbor freight tool. The momentary spike of Isc( before the current settled down) fried the meter. Now it only measures voltage. That's what $2.99 gets you!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    If you have the DC Current Clamp Meter--You really do not need to measure Isc... You can discharge the battery (or turn on some loads) and measure the current and voltage at various points in the system (solar array, between controller and battery, and at battery bank.

    Depending on the charge controller you have (less expensive PWM or more expensive MPPT), the solar panel may be OK, but the charge controller (or bad wiring) is limiting the current for some reason.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?
    BB. wrote: »
    If you have the DC Current Clamp Meter--You really do not need to measure Isc...

    -Bill

    You do if you want to know what the panel is capable of. Otherwise finding out you only have 2 Amps going to the batteries tells you you only have 2 Amps going to the batteries, not how much current potential there is.

    When you're diagnosing a whole system you have to check each component in turn until you find the one that isn't working right.
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Heading home for lunch soon and wouldn't you know it we have overcast skies. Full cloud cover but just light gray not dark and pretty high up. This panel is a polycrystalline unit supposed to still function somewhat in low light conditions. With a spec of 5.9 amps Isc I should still see at least an amp shouldn't I?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Depends on how dark the clouds... Easily 50% less, I have seen 90% or less from my array on dark/gloomy days.

    Part of what you are looking for is that the voltages look good for what should be happening. If your battery is 12.5 volts, and you have a PWM controller. The input should be around 12.5 to 13.5 volts or so... If you see 17-21 volts, then the PWM charge controller is not not letting the current through.

    Checking voltage at the individual batteries/cells, at the battery bank common bus point, at the charge controller output, charge controller solar panel connection, etc... Looking for something that does not look right (too high or too low of voltage, etc.). Then look for reasons why the voltage (or current) does is not as expected.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    When I was a Tech Controller in the Air Force we had a highly technical term for things that magically fixed them selves. "FM". Do we have FM here? Do solar panels have to be kicked awake?

    I did the short out test using my clamp on inductive amp meter and under these heavy clouds got 0.80 amps. Figuring this should be safe I used my harbor freight inline meter and got the same. What the heck? I never saw more than 0.21 amps all weekend in direct sun.

    Well, figured why not connect it back togeather and see what happens. Un-real. I'm getting 3 times the power now in heavy clouds I got all weekend in direct sun.

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Solar panels will put out their Voc with a very minimal amount of illumination. That's why Voltage is fairly useless for judging a panel. You want to see how much current it will put out, and that requires full sunlight. It drops off quite rapidly as the light dims.

    Isc will always be higher than Imp, and you won't ever see Isc in the real world because it needs a short circuit to produce it.

    I think I mentioned you can bypass the charge controller completely and see what you get, but an Isc of 0.8 shows you don't have enough sun to bother with. Really need that bright light.
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    The clouds cleared for a bit to a light haze so had to run home and check. Time I got there clouds were back and voltage was 16.8 steady with amps holding at 1.16. Doc said he saw a peak amp of 4.16. Previously with the 21 volts the amps were all over from 0.05 to 0.21. I do believe it's working now. Did shorting out the panel somehow kick it into gear?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    No--Not likely "fixed" by this...

    However, you problem may have been a poor electrical connection... Either inside the panel (bad) or somewhere else (jbox, controller wiring, etc. -- Fixable). So--Fix may be temporary or permanent--Depending on where/what went wrong and what connections you may have cleaned/tightened.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • unyalli
    unyalli Solar Expert Posts: 121 ✭✭
    Re: Hello and anyone feel like helping me troubleshoot a new system?

    Well, thanks all for the assistance. Don't want to admit it but had to be a connection. I went over and over them multiple times last weekend.

    This is for boondocking in the camper. Going to mount two 6 volt GC2's on the tongue and install controller in forward external storage compartment. Not concerned with A/C, Microwave, or anything else drawing big power. Need to power the RV water pump, LED lights, Fridge control panel, and a Satellite radio boombox.