solar panel add on

Discussion in 'General Electronics Chat' started by robertolson, Sep 13, 2009.

  1. robertolson

    Thread Starter New Member

    Sep 13, 2009
    I have four used panels approx 8 in. x 8 in. with regulators. All panels and regs check out ok. around 18v raw and all @ 13.7 v regulated. My problem
    is how best to use them along with my existing panel which is also regulated
    @ 13.7v. Would it work best to wire them into my existing regulator (parallel
    to my existing panel) or use one of the regulators to control all four 8 inchers and wire that parallel to the existing panel or regulate each 8 incher and wire them along with the existing all parellel? This would be to charge a 12 v lead acid battery.
  2. kkazem

    Active Member

    Jul 23, 2009
    If you want to parallel them, I recommend that you diode isolate them using a good sized 40 to 45v PIV Shottky diodes on each one to prevent back draining, unless you have a schematic and know that all the regulators also isolate (are they all the same??).
    If they are internally transistor or diode isolated, you can probably directly parallel them if the outputs are all set to a maximum of 13.7v or are at least all equal within a few hundred millivolts dc. There's no need for isolation resistors as the panels are already inherently resistive or act more like current sources, so they should parallel well. The isolating diodes may or may not be needed, but I would hate tu have your regulators blow by not being cautious. If you have a schematic of the regulators please post it and I can determine if iso diodes are needed or not.

    Kamran Kazem
  3. HarveyH42

    Active Member

    Jul 22, 2007
    By regulator, do you mean 'charge controller'? A charge controller would check the voltage of the battery, and stop sending current when its fully charged, so would sense the other panel as a fully charged battery?
  4. robertolson

    Thread Starter New Member

    Sep 13, 2009
    I an unable to make out anything on 3 of the regulators. They are all different. However on one regulator the following is readable:

    Make- Input/Output, Inc
    Solar Regulator 3A 12V
    PC 1381810001A AY 1381800001E (the "E" is written in freehanded)
    S/N 22943
    M505220 (also written in freehand)
    The unit is 3.25" X 3.25"

    The panels themselves are all identicle