Can I tell what wattage my solar panel is?

[Bobbo]

When I bought my Airstream, part of the deal was the dealer add the Airstream solar panel package. The Airstream package said I would get an 80 watt panel, a PWM controller, and 2 AGM batteries.

They did install a solar panel and PWM controller, but I had to email Airstream and get them involved before the dealer would provide the AGM batteries (which they finally did).

Not that I don't trust the dealer, but is there any way I can tell what wattage the solar panel on my roof is?

[Bobbo]

DownTheAvenue wrote:
If this "Airstream solar package" is actually an Airstream product that they stocked and sold, then a simple call to Airstream will probably get your answer.

That is the issue. I don't trust the dealer. If it was the true Airstream package, it should have had the batteries in the first place.

I am going to start by just measuring the surface area of the panel as a crude estimate.

Thanks all.

[DownTheAvenue]

If this "Airstream solar package" is actually an Airstream product that they stocked and sold, then a simple call to Airstream will probably get your answer.

[Ivylog]

10 square inches/watt is a pretty good rule of thumb...so the 780 above is what you should be able to measure for yours.

[Chad_Heiser]

Watts = Amps x Volts

Do as described above to get a close estimate of the panels wattage. However, the number you get will be less than the actual STC (Standard Test Conditions) rating of the panel. This is because STC ratings are for idyllic conditions that cannot be attained in the real world.

If you can get your phone under the panel near the connection box, you could also move it around and snap some pictures of the underside of the panel to maybe get a snapshot of the label and see the ratings.

[time2roll]

Label on the back most likely. Or measure it and compare. They are very similar in wattage per square inch when comparing similar sizes. 80w is maybe 39x20 so 780 sq. in.

https://www.solarblvd.com/products/solar-cynergy-80-watt-12-volt-solar-panel-4/

[MrWizard]

disconnect the leads coming from the panel to the controller
leave the battery output leads connected

set a digital multi meter on 200 DC volts
measure the voltage across those leads, should be 18 - 23 v
this is the VOC 'voltage open circuit' aka NO LOAD

now set the same meter DC amps, connect to the "10 amp" jack on the meter
now measure the amps
you reading the max short circuit amps

post the results here
a 2-3 amp reading is a 40w panel a 4-6 amp reading 80w or more

do this in high sun no shade on the panel

OR
you can unbolt the panel and read the specs on the label on the back of the panel