Can you overpanel a Blue Sky Controller?

st4rgut
st4rgut Registered Users Posts: 36 ✭✭
in Off Grid Solar & Battery Systems #1
Hi, I found a cheap Make Sky Blue MPPT Controller online and want to meet the max power rating of 1440 Watts for my 24 Volt system on overcast days. I've got enough panels to harvest the maximum power on cloudy days but I'm worried because the specs of the controller on the seller's site says, "(The total power rated of PV can’t be over this watt that will break the controller.)" Yet, I've read on forums that charge controller's can tolerate exceed max pv input rating as long as the panels stay within the max pv input voltage. I also saw a youtube reviewer mention his Blue Sky controller may have some sort of current limiter in it. Has anyone using Blue sky MPPT controller tested its max power limits?
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  • 706jim
    706jim Solar Expert Posts: 519 ✭✭✭✭
    #2
    What is the warranty? The controller may absorb an overcurrent for a time or may just blow up. My old Trace C40 PWM controller is rated at 40 amps yet has survived short periods of up to 58 amps
    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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  • st4rgut
    st4rgut Registered Users Posts: 36 ✭✭
    #3
    1 year warranty
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  • st4rgut
    st4rgut Registered Users Posts: 36 ✭✭
    #4
    Just called Sean Buckner, the USA rep for Blue Sky. He says no, the controller can't handle above max pv input and I would have to wire controllers in parallel to achieve that.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    You do have to be very clear on what "over paneling" means... Do they mean over voltage of over current on the input? 

    Over voltage on the input--Obviously not a a good idea.

    Over current (over rated Watts/Vmp-array) available on the input--There is what the controller electronics can handle vs what the wiring/connections are "Rated" for for safety (have seen 45 Amp rated output and 45 rated max input current--But Watts could be over rated.

    And to be honest, the answer you are going to get from the company is to follow the manual. You probably are not going to talk to the designer to get the details (such as you can over Watt the controller, but not over current the controller input).

    For longer life (electronics, and most anything), running at less that "Rated power" is going to keep the controller cooler and give you that longer life. (as always, have good air circulation and a cool environment... Don't install in a hot/sunny room, with little airflow).

    -Blll
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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