Solar Panel Output

rrcbov

I’m trying to understand this whole solar equation.

According to NuCamp the panel on my Tab 400 is 162 watts.   I was recently in Hobe Sound Florida - cloudless day, no shade - and recorded P max of 83 watts.   Does this make sense - I guess I thought it might be much closer to the 162 watt spec.  I’m trying to make sure my components are working correctly.

manyman297

I believe it depends on the state of charge on the battery. If it’s mainly in “float” charge then you’ll barely generate any watts because the battery is almost or already full. I too was alarmed when our 400 was showing 2w being generated on a sunny day and it turns out the battery was full and in float. 

VictoriaP

A few additional things that can impact solar energy capture:

- Panel efficiency (none of them are 100% efficient, and you lose a bit to cable runs as well)
- Panel angle
- Panel direction
- Sun angle/time of day/time of year
- Dirt on panel surface

You’ll rarely see maximum numbers from a panel adhered to a curved surface. The trailer has to face exactly the right way and the angle has to be just right to get full production. I was testing a 100 watt portable panel the other day right at noon, and the output fluctuated by as much as 20 watts just by changing the angle of the panel.

dragonsdofly

@rrcbov, I agree with @manyman297, if your battery was full or nearly full, the solar controller is passing only few trickle watts into it to keep it topped off. We have a large trailer with 1,400 watts solar. In full sun we can generate almost the rated 1,400 watts (all are fixed monocrystalline panels) but when the batteries are full, we show 4 or 5 watts being generated because that is all the batteries can absorb at the time. Your solar controller is doing a great job by not letting the battery(s) get overcharged. All is working as it should.

MarkAl

Not mentioned but it really is the battery charge current AND any trailer loads assuming the panel has sufficient solar energy impacting it.