Sizing Panels

goldcoaster · Senior Member

Sizing Panels

Whenarewethere · Guru

With ideal weather at the middle of the day. Measure the amps & voltage coming into the controller & calculate the angle of the sun & factor this in. Repeat a few times to average results.

The other option is measure the actual area of the solar cells themselves, not the overall panel, & use a conservative factor of say 130 watts per square metre. If the are new panels say 150 watts per square metre.

Whenarewethere · Guru

Ideally they show be wired in, in such a fashion that you can measure each one individually, this could be wired in with individual switching. A DC clampmeter is a great tool to check everything.

Jaahn · Guru

Hi Mick smile

I would measure the size of them and just look on the web for similar sized panels to get some idea of the power. Sometimes you might get a mobile to take a pic of the specs label by sliding it under. hmm

If you want to know if one is not working then assuming you have an indication of the power or amps of them all, get out in the bright high sun, cover the panels with thick blankets or similar, and uncover one at a time and see how they compare. Do not fall off the ladder though. wink

Obviously a clamp meter would be easier but only if the person who wired it left the wires available to get around individually and I have not seem that often.

Jaahn

-- Edited by Jaahn on Wednesday 2nd of June 2021 02:43:42 PM

Peter_n_Margaret · Guru

Comparing them to others on the market is risky because many are severely overstated (and fraudulently so).
Unless they are particularly good (or bad) they will be about 150W/m2 under test conditions.
In full sun they will produce about 70% of that.
Covering or clamp meter or disconnecting one at a time is the only way to get a reasonable actual.
Cheers,
Peter