Recycling Arco panels for a battery charger

706jim
706jim Solar Expert Posts: 519 ✭✭✭✭
in General Solar Power Topics #1
My initial foray into solar power dates back to 1994. I purchased 7 Arco panels (about 1' x 4') five of them "Bronze" and two of them "Gold". These were salvaged from a solar farm in Arizona (I was told) and are brown in colour. 7 of these in series give an open circuit voltage of about 42-44 and they used to deliver around 5-7 amps when charging through an old AMPS on/off charge controller.
The rating for this group was about 170 watts. I am thinking of using these as a battery maintainer for my boat since they contribute very little to my present array.

So the question to the group is this: How many of these should I use to avoid overloading a simple PWM controller that would be charging two group 31 12 volt batteries in parallel?

Would it damage in inexpensive controller (none purchased yet) if I fed the whole 42 volts into it?

Or would it be preferable to use about four of them in series (they're about 6 volts VOC)?

And for nostalgia's sake, this group was about $700 USD back in 1974!
Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,101 ✭✭✭✭✭
    #2
    Series 3 at a time for a 12 volt battery and PWM controller So you can go3s2p. or all 6 in series with a true MPPT controller. Beware of the cheap controllers labeled MPPT, they're not MPPT. 

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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