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TominTampa's avatar
TominTampa
Explorer
Jun 09, 2017

Old Solar Panels

Hello All,
I'm finally getting around to a little solar upgrading, (nothing big, just to maintain the batteries). I've got a new Prostar PS-30M controller, but I haven't purchased my new solar panel yet. My question is that it looks like right now the most my 21 year old solar panels bring in is 1 amp! I know technology has progressed in the last 21 years but boy does that seem low? The house batteries are sitting at 13.0 volts and the old solar panels are only bringing in 1 measly amp. Even when I put a load on the house batteries, it's still just an amp of solar power. Can anyone chime in with any old solar stories from days gone by? I believe the old panels are Honeywell panels, I'm going to include a photo of them below. - Tom
Class A
  • 2oldman's avatar
    2oldman
    Explorer II
    Jun 10, 2017
    Sure sounds like those panels are shot. You may find burned out spots on the wiring on the front.
  • azrving's avatar
    azrving
    Explorer
    Jun 10, 2017
    Isolate the panel wiring and check voltage and short circuit amps tilted to full sun.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Jun 10, 2017
    "nothing big, just to maintain the batteries"

    Solar can be so much more than "maintain the batteries." Think bigger.
  • KD4UPL's avatar
    KD4UPL
    Explorer
    Jun 10, 2017
    What are the panels rated? It's impossible to tell from just a frontal picture.
    Tilt the panel so it's aimed directly at the sun and measure the open circuit voltage. Then, short the output and measure the current. See how these measurements compare to the label that is hopefully on the back.
  • MrWizard's avatar
    MrWizard
    Moderator
    Jun 10, 2017
    there could be a corroded connection, or a few bad cells
    a few look light blue, maybe water damaged
    a bad cell in a string of 11, pretty much kills that string

    i count 33 cells, (3 strings per panel) if i'm correct those are 16.5v panels

    one panel has fuzzy cells in all 3 strings
    the other panel has 1 string with fuzzy cells
    and 2 strings that are all clear dark blue
    it might be only (2) full working cell strings in your setup

    you need to do a meter check and see what they give the batteries when there is load on the batteries
    turn on all the lights and see if the solar output goes up
  • Ed_Gee's avatar
    Ed_Gee
    Explorer II
    Jun 10, 2017
    I can say with some certainty that those are 50Watt panels. New, you had 100W available. Mr. Wizard has pointed out that you may have water damaged cells..... do as many others have already suggested and disconnect the solar panels from everything and do a short circuit current measurement. You should see at least 3 amps in full direct-on sunlight from each panel. An open circuit voltage measurement should give 18 - 22 volts.
  • TominTampa's avatar
    TominTampa
    Explorer
    Jun 10, 2017
    Everyone,
    Thanks for the replies! Looks like I'm going to have to do some more research up on top of the roof! Thanks again. - Tom
  • azrving's avatar
    azrving
    Explorer
    Jun 10, 2017
    I have used this tool to easily see amp output from the panel. Fuse buddy. Just connect the two panel wires to the two blade terminals and you will read amps.
  • Ed_Gee's avatar
    Ed_Gee
    Explorer II
    Jun 10, 2017
    Most digital multi-meters can measure up to 10 amps of current. After checking the rating on your Meter you can simply put the leads across the output wires from the panel to measure short circuit current.
    BTW, should your two old panels prove deficient, you should be able to find the equivalent wattage in a single new panel for around a dollar a Watt.

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