Getting .6 amps from a 60 watt panel!

System
System Posts: 2,511 admin
in Advanced Solar Electric Technical Forum #1
I bought a panel that had several cracks in the glass -- I tested it and it seemed to measure 17.X volts -- I know, I should have brought a multimeter and measured voltage, current, etc. but I didn't think it would have any cracks in it. Live and learn.

Anyhow, I'd like to know if I should measure short circuit current, or current under an actual load. Right now, my expensive SolarBoost 200E charge controller is reporting 0.6 amps from the solar panel -- that would be the equivalent of a 10 watt panel.

I might have to pry off the broken glass and start testing the various connections between the individual cells. That doesn't sound fun!

Before I do that, I want to make sure that something is indeed wrong with the panel.

I have very short wiring, 12 AWG, and 2 Trojan T-105 6V batteries combined into one 12V. I have it facing the sun at an angle, with nothing obstructing it, etc. I live in Texas, so the sun should be delivering a lot of power this time of year.

Thanks,

Matthew
· Share on Twitter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Getting .6 amps from a 60 watt panel!

    Measuring short circuit current will tell you if the cells/wiring have been damaged by cracks/poor connections.

    Voc and Isc will probably give you 90%+ confidence in the panel's health.

    My guess, measuring under load will also help you measure possible sun damage/degradation (typical issues with "inexpensive" amorphous solar panels). Problem is that this is a pain in the but (haul partially discharged battery/load+MPPT controller+meter...).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #3
    Re: Getting .6 amps from a 60 watt panel!

    Cracked glass is the same as parital shading ... I've had panels just like that and seen results anywhere from 10-30% of nameplate

    By the way, a cracked cell typically has no effect on the power output, as most solar panels have redundant metal to carry the current for each cell
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #4
    Re: Getting .6 amps from a 60 watt panel!

    I have another question --

    If I have to buy more charging capacity (solar panels, etc.) I was considering buying some small fan-like windmills. I don't know if anyone has heard of MotorWind.

    Anyhow, I can get 4 KW/h per day capacity for $450 or so, including shipping. Problem is, the specs say that they generate "12 -100V, unregulated".

    So how hard would it be to turn that excess voltage into more current -- since my charge controller can only handle 30V.

    I could go with a new solar panel, but an 80W panel costs more than these 20 small "micro-windmills", and it would only generate 80W * 8 hours (640W) instead of 4 KW.

    Matthew
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #5
    Re: Getting .6 amps from a 60 watt panel!

    My next question --

    I bought a piece of glass for this panel (cost me $60!) and I used silicone to attach it to the panel. It worked well, and was probably waterproof. But I removed it, thinking the glass might be reflecting some of the juicy UV rays so the panel wouldn't get as much. Also, I thought it might be acting as a greenhouse to make the panel even hotter.

    Should I remove the cracked glass, and perhaps re-silicone my new sheet of glass over the panel to protect it? It sounds like it could work. If I can't get much amperage otherwise, I might have to test the cells anyhow. I don't think I'll ever be able to charge my 2 6V 220 AH batteries with .6 amps of charging... that's more like a trickle charge!

    Matthew
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #6
    Re: Getting .6 amps from a 60 watt panel!
    Solar Guppy wrote: »
    Cracked glass is the same as parital shading ... I've had panels just like that and seen results anywhere from 10-30% of nameplate

    By the way, a cracked cell typically has no effect on the power output, as most solar panels have redundant metal to carry the current for each cell

    by my calculation, I should be getting 3.50 amps if this is a 60W panel (which I'm pretty sure it is -- it's 3 feet by 2 feet Holec brand.

    I'm getting .6 amps -- so that's 17.1% of it's rated value.

    Matthew
    · Share on Twitter
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #7
    Re: Getting .6 amps from a 60 watt panel!
    CathInfo wrote: »
    by my calculation, I should be getting 3.50 amps if this is a 60W panel (which I'm pretty sure it is -- it's 3 feet by 2 feet Holec brand.

    I'm getting .6 amps -- so that's 17.1% of it's rated value.

    Matthew

    Sound about right, all those cracks is shading to the cells
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #8
    Re: Getting .6 amps from a 60 watt panel!

    I just went outside and tried to remove the glass -- not successful. This particular panel (Holec) has a rubber backing, and the glass seems to be glued to the individual solar cells. I started with an area that had the worst crack damage -- and started near the frame (so as not to damage the cells underneath) but I nicked once of the cells anyhow.

    I wish this panel had been in a thicker frame -- with some space between the cells and the glass covering. Then my job would have been easy!

    I didn't realize just HOW MUCH damage was done to the panel when it had cracks on it. I thought it might get 5 or 10% less energy. But it's getting 83% less!

    I wonder if there's any way to fix it... probably not.

    Matthew
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #9
    Re: Getting .6 amps from a 60 watt panel!

    How important is it to ground your solar panel? I haven't done so, and I was wondering if that might be causing a problem.

    Matthew
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #10
    Re: Getting .6 amps from a 60 watt panel!

    Probably not... Usually the glass, adhesive, cells, backing are all vacuum laminated together. A huge mess to try and get apart.

    Pulling out the individual cells for experiments is about the best you can get from this.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #11
    Re: Getting .6 amps from a 60 watt panel!
    CathInfo wrote: »
    I have another question --

    So how hard would it be to turn that excess voltage into more current -- since my charge controller can only handle 30V.

    Very hard, except for the 4 days a year you get winds over 30 MPH.

    Skip the idea of wind, unless you live in a VERY windy area.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #12
    Re: Getting .6 amps from a 60 watt panel!

    Actually, these MotorWind devices aren't really windmills. They are an array of small turbines, which only require wind speed of 2 m/s to start generating.

    Apparently they work quite well.
    · Share on Twitter
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #13
    Re: Getting .6 amps from a 60 watt panel!
    CathInfo wrote: »
    Actually, these MotorWind devices aren't really windmills. They are an array of small turbines, which only require wind speed of 2 m/s to start generating.

    Apparently they work quite well.
    (according to the sales hype)

    Any installed anywhere ?

    http://www.motorwavegroup.com/new/motorwind/product.html

    Well, let us know how well they work for you, but don't say you weren't warned.

    Array of 20 @ 2 MPS (4.48 mph) generates 1 watt
    Array of 20 @ 5 MPS (11.2 mph) generates 15 watts

    I'm not going to worry too much about my batteries overcharging.

    MPS - MPH conversion
    http://www.energy.iastate.edu/renewable/wind/wem/conversion_table.htm
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #14
    Re: Getting .6 amps from a 60 watt panel!

    But then it really goes up from there.


    5 m/s = 11.2 mph gives you 15 watts
    7 m/s = 15.68 MPH gives you 42 watts

    and it goes up rather drastically from there.

    The problem is, what voltage is that power delivered in? What can I do with 50 volts at .81 amps? I'd rather have 17.1 volts at 2.46 amps. (you get the idea)

    And these devices charge your batteries 24 hours -- not just from 10 AM till 6 PM. Tripling the number of charging hours certainly helps --

    I look at it like: how much solar panel could I buy for $350? A single 60 watt panel. That would only bring in 60W X 8 hours = 480W.
    Say you came in between the two above: 13 mph wind for 25(?) watts. 25 X 24 hours = 600W. And if you could get 15 MPH wind, you'd have 42 X 24 = 1000W. Anything "windy" (greater than 15 MPH wind) and you'd really be raking in the energy.


    Matthew
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #15
    Re: Getting .6 amps from a 60 watt panel!
    CathInfo wrote: »
    I have another question --

    If I have to buy more charging capacity (solar panels, etc.) I was considering buying some small fan-like windmills. I don't know if anyone has heard of MotorWind.

    Anyhow, I can get 4 KW/h per day capacity for $450 or so, including shipping. Problem is, the specs say that they generate "12 -100V, unregulated".

    So how hard would it be to turn that excess voltage into more current -- since my charge controller can only handle 30V.

    I could go with a new solar panel, but an 80W panel costs more than these 20 small "micro-windmills", and it would only generate 80W * 8 hours (640W) instead of 4 KW.

    Matthew
    =
    =========================================
    Before you blow ANY money on that miracle windmill, take some time and read up on posts and the experience of those, including myself who have spent money on such things. They're much like the famous Q-Ray.
    Cheers
    Wayne
    · Share on Twitter
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #16
    Re: Getting .6 amps from a 60 watt panel!
    CathInfo wrote: »
    How important is it to ground your solar panel? I haven't done so, and I was wondering if that might be causing a problem.
    Matthew

    For testing, grounding a single panel does nothing. Actually, grounding panels is only for lighting protection and to make inspectors happy.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

    · Share on Twitter

Categories