Solar Percentage (location/Season)

[Jon and Kay]

Is there an App or program that calculates the expected solar output from a panel laying flat (on MH) at different Lattitude and times of year?

I seem to be averaging 62% in Emerald in Winter. Does that appear right?

[T1 Terry]

Anything better than 50% in winter is a bonus, especially in the southern states, but Emerald would be better than say Tassie. The accepted figure of 70% seems to be a fair estimate for flat mounted summer output, but I have seen over 90% going into the lithium batteries at times and 110% when freak weather conditions of light scattered cloud and close to large lakes/ocean to get the reflected effect. There is another effect they term cloud edge but it is very short duration so not something you would use in any sort of calculations..... but some have been known to use these spot figures to claim a superiority of one controller over another. Genuine comparisons are made on full day harvest, not spot figures, and then generally average over a week or so to level out the effect of optimal days that suit one device over another.

[Jon and Kay]

Thanks Terry, I currently have 1100 watt of solar at 12vnom so say 60ah. When I changed from running through the PL40 to running through a 100A SSR, I was in Cairns, and was harvesting up to 70+ah in circumstances where there was a lot of cloud edge. Then the rain came, and I headed South as they didn't have a tropical dry season this year. The Relay method (controlled by PL40) is far more efficient than running directly through the PL40. I think the PL40 temperature compensation dampens the output when all the current goes through the controller.
The biggest difference for me is at the beginning and the end of the daylight, I get much better harvest for the first and last couple of hours of sunshine.

[T1 Terry]

Definitely, and the output seems to climb ever so slightly after it first starts up from an over cell voltage cut, say it was 55 amps before the cut, it returns at 30 and rapidly climbs to 50 but slowly climbs to 53 amps or even 55 amps again.... no idea why that occurs but I'm not the only person to observe it with their systems once they were changed to the SSR control method. Had a Victron sales person trying to tell me the output would be better with one of their MPPT units, so I challenged him to a $100 bet and I get to keep the Victron unit if it didn't out perform the Plasmatronics/SSR method...... he wouldn't be in it

[Jon and Kay]

As usual, you are right Terry.
Have you looked at http://www.efficientenergysaving.co.uk/ ... lator.html ?
Found it after asking the question.
Seems to confirm what I have been experiencing.

Think I'm very happy with the PL40 I bought 8 years ago, coupled with the SSR and heatsink from Jaycar I bought two months ago.

[T1 Terry]

Another thing to consider, the instant amps x the 13.6v for a lithium battery recharging converted to watts, then compare that to the advertised watts on the panels and the harvest can be quite a bit more than the accepted 70% that PWM is supposed to be limited to, but some people on another forum don't seem to want to know about that

[Jon and Kay]

I can't see a MPPT controller beating the harvest of a PWM controlling a SSR, especially under low light conditions.
My experience doesn't include a MPPT, but those who argue their benefit seem to do so under best solar conditions.