50 solar cell battery charger wiring?

Discussion in 'The Projects Forum' started by usrmpz, May 14, 2009.

  1. usrmpz

    Thread Starter New Member

    May 14, 2009
    I just bought 50 solar cells and I am ready to begin wiring them to make a panel, the cells are .5 volts each, 1.7 watts each and 3.5 amps each. I am going to use the panel to charge a 12 volt battery which will power an inverter for a few odds and ends. I read the difference in series and parallel wiring, I understand that series wiring increases voltage, and parallel increases amperage. What would the recommended sequence be for using my 50 cells together on a panel to charge a 12 volt battery? Should I wire them as series until I get 18 volts (36 cells, right?) and then wire the remainder as parallel to increase the amperage? I’m a little unclear as to how I can get the most out of my cells for the purpose of battery charging. If my calculations are correct, these 50 cells would create an 85 watt panel. Also, how many cells make an ideal size panel? If this goes well, I will be buying more cells to expand my project. Any help would be appreciated. Thanks
  2. DonQ

    Active Member

    May 6, 2009
    There isn't a way where you can have 36 in series and the rest of them in parallel. You really only have the options of 50x1, 25x2, 16x3 (with 2 left over), etc.

    Since you need 30-36 in series (anything over 25) the only easy option you have is to just sit on the others till you expand.

    There are ways to get power off the cells at one voltage, and electronically convert it to a charging current at a different voltage for your battery. This might be more than you want to do, but it would let you use all your cells, and also give you the option of using the cells at the voltage where they provide the most total power. The max power is different than either the max voltage or the max current values.
  3. Externet

    AAC Fanatic!

    Nov 29, 2005
    Buy 10 more equal cells and wire 30 cells in series in one panel, make a second 30-cell panel and put both panels in parallel.

  4. Bernard


    Aug 7, 2008
    Here is a plot of a solar battery float charger, 1 PM Tucson AZ. It backes up what DonQ had to say about maximum power.
  5. SgtWookie


    Jul 17, 2007
    I don't really have anything to add to this thread at this point, despite your PM.
  6. usrmpz

    Thread Starter New Member

    May 14, 2009
    Thanks for the reply's everyone, my question was sufficiently answered.