100 watts to 600 watts within a minute same sun

blueblue Registered Users Posts: 35 ✭✭
Ive been watching the voltage on my panels. It will sometimes jump from 100 watt output to 600 watt output within a minute with the same sun. Ive seen some variances even under load but mostly I have pretty good output. I have 1500 watts in panels at 8 -12 volt batteries at 24 volts . I was wondering if the 60amp epever solar controller would cause this in charging the batteries? Or perhaps the panels have an intermittent short somewhere. The panels are 3 banks of 5 panels at 100 watts each. 


  • mcgivormcgivor Solar Expert Posts: 2,394 ✭✭✭✭✭
    Difficult to say, if there are loads or clouds these factors could cause swings in wattage, but the interrelationship between voltage and power would be a better way  to determine if there is an issue, or if what's being seen is merely a dynamic change based on conditions. 

    The battery regulates the voltage, if the voltage drops along with power there could indicate a problem in the array or a passing cloud, if voltage remains stable but power increases that could indicate a load cycling on. Battery capacity along with state of charge will influence the degree of the swings, so in order to conduct a test the conditions would have to be controlled, no loads on a clear day with the battery partially discharged. This would allow the PV to provide as much current as conditions allow without being influenced by another factor, then carefully watch the voltage and wattage, or current depending on the display, there should be no radical swings. The type of controller PWM or MPPT is not mentioned, but PWM should remain more stable, clamped to the battery voltage whereas MPPT may vary in power to some degree as it tracks the maximum power point but these swings would be subtle, not major. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
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