Solar panel rating

[kb0zke]

If a panel is advertised as a "100W" panel, does that mean that it will deliver 100W per hour under ideal conditions?


I realize that in the real world ideal conditions are seldom seen, but one has to start somewhere.

[waninae39]

yES, only under IDEAL conditions
many factors affect total power output
typically you get about 30-70% depending on location, orientation, shade, sun angle, TOD etc

[kb0zke]

Thanks for the quick response. That's what I thought, but the older I get the more I question what I think. Maybe I should just stop thinking.

[field & stream]

I think the rating is only achieved (if ever) in a laboratory setting. Marketing BS.

There are so many variables in the real world that it is hard to even generalize. You might get 70% of that for a short while best case, but even if you are chasing the sun and there are no clouds or shade in my experience you will be doing well to get 30Ah per day per 100w of panels.

Add clouds and/or shade and the closest round number is zero.

[PaulBristol]

2025 Trade Wind with 600 watts of solar on the roof produced a maximum of about 400 watts peak in Texas desert sun in March.


It produce about 150 watts peak in Wisconsin sun in February.

[thiel]

I have 400w of panels, but the best Ive ever seen is about 375 (though to be fair the panels are tilted a little away from each other due to the rounded roof.)

[O-side Jimmy]

Down grade the rating as follows: 10-30% based on location (closer to the coast is more of a downgrade), 10% more if MultiCrystal (vs. Mono). Use 5-5.5 hours of production, less if at a higher Latitude. If Inverting to 110VAC, another 10%. I’ve been playing with PV since 1981. I was the BD Mgr for the largest mfg and deployer of PV. I also put the very first PV panel on an RV (a sailboat in 1982).

[vanderwielen]

Yes, and in some cases more with quality products. variables are the angle of the sun (do trigonometry), the haze in the air, the SOC of the accepting battery bank... but generally assume you get the rating. Here's a shot of my 315W of Zamp roof mount panels driving North with a slight uphill drive in March at noon in New Mexico. When using Victron MPPT products a bit of overhead or over-paneling is allowable. Their 30A 12v allows a max of 440W harvest. (image failed but the harvest on this array was 343 watts)

[Peter C]

Previous trailer I had "made in china" panels and with a high quality charge controller I never saw anything close to rated output. With my Airstream I went with the higher efficient Renogy Eclipse 100watt x 4 panels and have seen higher than the rated 400 watts of output (July close to noon full sun). Paying for higher quality "made in USA" panels was a good investment. I also purchased 200watt portable renogy eclipse suitcase (using an external victron mppt controller) and also see very close to 200 watt but generally I do not use the portable system as much.


I strongly suggest to purchase quality.

[JCWDCW]

We have 1 x100 watt solar. I have seen 6 amps but our batteries were at 11 or 12 volts so likely some resistance to taking more amps
Keeps our 2x100AH AGM topped up nicely. We have boondocked 3 days on a Caravan with minimal sun. We don’t use inverter power for anything and our 2012 International has the absorption fridge.
Enough for our needs but likely not for many who have to run the 110 volt appliances and have the new compressor fridge

[RThorn]

Try this: https://pvwatts.nrel.gov/

Its designed for residential applications but it will give you a good sense for the impact of the weather, pitch, inverter efficiency ,etc. Remember, if part of a panel is shaded you may lose power for the whole panel. Buyer beware. Good Luck

[ORFC25FBT]

My Home Infinity Solar 410 watt panels runs about 75-78% during sunny days in Central Oregon. My EcoFlow Panels at my campsite run as high as 95% on the 220-watt bidirectional units. My 100s and 400s run about 80%. Very pleased with EcoFlow system. 3,200 watts of solar, Delta Pro x 2 and Extra Batteries x 4 storing 21.6 KW. Smart Generator running propane never gets a workout unless it rains for more than five days straight.