Eco-Worthy 12v solar panels, Now drifting to... mono vs poly

Snowman9000 wrote:


Jim, I'm wondering if your mono-poly results simply reflect one bad mono panel?

I had heard that suggested before and had excepted it as a possibility until I got the pair of 245w monos and they showed the same caricaturists.

I had no controller for the first year that I had my panels, so I would drag them out to the yard in all kinds of weather. I'm not a highly techy person so all I had was a handful of meters and would record the Voc and Isc. When temperature was being discussed, I taped a thermometer to the back of the panels and kept track of that too.

These are just my unscientific observations.

The monos in bright light reach a higher Voc than the poly does. On a cold winter day the 220w went over 40v for a few minutes and then settled down to a working Voc of 38v. Those extra volts only translated to 3/4 of a amp additional output. Drop the light level and the Voc drops quickly and can get down into the 20's where there isn't enough for the controller to do much.

The poly is more consistent with it's Voc. It usually runs around 34v, maybe 35v and when the light drops, it stays above 30v. The 230w poly is noticeably bigger than the 220w mono and slightly bigger than the 245w mono.

I may as well for reference add that amorphous panels have the largest foot print and the best ability to collect power in low light.

So the monos are tuned to bright light and almost treat low light like its not worth the effort. Polys are the middle of the road, needing a bigger footprint than monos in bright light, yet can't collect as much as amorphous in low light.

So if you are in Arizona where the sun is intense...Mono.

In Sunny Colorado where the pattern has been morning sun and afternoon clouds...Poly

In the PNW I'd see if I couldn't get enough amorphous panels up there to cover my needs.



Last thing is I would have never known there was a difference without spending the time with the meters on the different panels. I would have looked at the drop in power on the monos and thought "well it's cloudy stupid, what did you expect"

Again, just my unscientific observations, nothing to base your personal decision on. Even weirder is I believe different controllers have sweet spots with Voc and matching up the right controller to my panels will get me more. (now you know why it's taken this long to mount. lol)