niel wrote: »
...the middle one is at latitude +15 because the latitude is only representing the highest point in the sky the sun reaches in the day and most times the sun sits lower to the horizon before and after solar noon. the +15 degrees semi-compensates for the lower to the sky angles without overly compensating due to side to side excursions. remember that solar noon +/-1 hour represents about 15 degrees to the side of solar noon so that 1 hr before and 1hr after solar noon the pv will only be off by 15 degrees and a tad more than 15 degrees at solar noon itself giving a bit more power from the off solar noon times.
inetdog wrote: »
This also means that if you have a seriously East or West of South facing angle for the panels, the sun will be lower in the sky during their peak production too, especially in winter, so adding even more degrees can be better.
waynefromnscanada wrote: »
Thomas, I'll try to explain MPPT controllers for you. (For simplicity in this explanation, we'll ignore all system losses etc.)
Lets assume you have a solar panel capable of putting out 5 amps @ 36 volts at it's most efficient point electrically. Now you take that panel and connect it directly to your 12 volt battery (or through a PWM controller). The battery instantly loads down the panels to say 12.7 volts, but the amperage stays at 5 amps. What the panel is CAPABLE of putting out is 5X36=180 watts. But you have reduced that to 12.7X5=63.5 watts. You've just installed a system that's throwing away over 115 watts!
Now, replace your PWM controller with a MPPT controller and everything changes.
Your MPPT controller, electronically finds that the Max Power Point of your panels is 36 volts, so it only loads the panels to that voltage. Thus what's going into your MPPT controller, is 36VX5A=180 watts. The MPPT controller, using it's electronics takes that 180 watts, and like an AC transformer, drops the voltage down to the battery voltage of 12.7, and since it has 180 watts to work with, it increases the current going to the battery to over 14 amps, even though the panels are only putting out 5 amps! This is the beauty of the MPPT controller and what it does.
Hope this helps you grasp the understanding. (Keep in mind that this is a very simplified description, ignoring all system losses etc for simplicity)
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
System output may range from 1,027 to 1,090 kWh per year near this location.Click HERE for more information.
* Caution: The PVWatts® energy estimate is based on an hourly performance simulation using a typical-year weather file that represents a multi-year historical period for Pueblo, CO for a Fixed (open rack) photovoltaic system. The kWh range is based on analysis of a nearby data site described here.The estimate for the value of this energy is the product of the AC energy and the average retail electricity rate. This value is useful for basic comparisons but does not account for financial considerations in a cash flow-based analysis. All of these results are based on assumptions described in Help that may not accurately represent technical or economic characteristics of the project you are modeling.