Hi Team, my Victron panels appear to supply close to the specified amps but down on power by 25%. As long as I’m getting the amps into my battery should I care about the reduced power? Thanks.
asked
Good current but low power
Power depends on illumination, temperature and angle to the sun, amongst other things.
The MPPT will maximise power, keeping panel voltage high, while adjusting current.
How much less than rated power are you getting, roughly where in the world are you and is there any shading of the panels?
Hi, I’m in Adelaide Australia. Midday sun directly overhead, clear sky, 25 deg C, and I’m getting maximum 110 watts from my 140w panel. VOC is down about 2 volts but ISC is about right. I have 2 new panels and both are same performance. I have a new Victron 100/50 controller on the way, I’ll repeat some tests and see how I go.
You're probably in the right ballpark with the panels. The max values are for standard conditions, one of these is panels at 25C. In bright sun with air temp at 25C, the panels will be a lot hotter than ambient and will give less power.
@genwest As the panel temperature increases the voltage reduces noticeably and the current increases very slightly, hence the power produced falls, what you are seeing is entirely expected. See
https://www.pveducation.org/pvcdrom/solar-cell-operation/effect-of-temperature
