sunny boy inverter?

[J.P.M.]

jpm-the thought that went into the array size was given a little thought our bill is never more than $150 a month, and that is in the hot part of the summer, i heat from a wood stove with just a back up heat pump that rarely kicks on. so i figured around 1500 kw-hr a month, this should offset about 2/3rds of that in the summer if i get at least 7 hours of sun (very modest estimate), the main thought was to have something that if we lost grid power for a long time, i would have back up to run a freezer, the sunny boy affords that without batteries (as long as the sun shines), up to 2kw.

ampster- attaching to the rail is definitely the way to go, thanks

Thank you.

[mudhole]

jpm-the thought that went into the array size was given a little thought our bill is never more than $150 a month, and that is in the hot part of the summer, i heat from a wood stove with just a back up heat pump that rarely kicks on. so i figured around 1500 kw-hr a month, this should offset about 2/3rds of that in the summer if i get at least 7 hours of sun (very modest estimate), the main thought was to have something that if we lost grid power for a long time, i would have back up to run a freezer, the sunny boy affords that without batteries (as long as the sun shines), up to 2kw.

ampster- attaching to the rail is definitely the way to go, thanks

[Ampster]

...............
from videos i have seen, cable management was basically plug them in series and just let them hang under the panel, is that the correct , NEC, way of doing it?

Most people clip the the cables to the rails instead of leaving them hanging. If you use zip ties use ones that will not degrade over time. I don't know what NEC says, but common sense is that you don't want them to chafe in in the wind cause a short or current leak.

[J.P.M.]

Mudhole:

Maybe this is a bit like closing the barn door after the horse got out, but did considering the electrical load you have and how much of that load you want to offset w/PV get any considertion in your planning/design ? I haven't seen any mention about how you came up with an array size.

[mudhole]

well the solar panels and the inverter have arrived, sunny boy 5.0 -41, and 18 talesun panels tp660p-275, still waiting on the rails

i plan on laying the panels out in 6x3 rows, running 2 strings into the inverter on separate mppt inputs, , the open voltage is 38.7 and the operating is 31.7, when i checked the panel it was around 37 volts, this was late in the day and i just stood them up, almost upright . this would give me about 330 volt string(well within the input range of the inverter), from videos i have seen, cable management was basically plug them in series and just let them hang under the panel, is that the correct , NEC, way of doing it?

[J.P.M.]

Go to solarpaneltilt.com for a thorough treatment of solar PV panel tilt angles....

FWIW, that's not a bad treatment of what are possibly good 1st approximations of fairly optimal tilt angles vs. season. Although I'd take issue with a few of the author's points such as always having an array azimuth that reads like it's supposed to be inflexibly normal to the equator, the suggestions given will probably keep most folks out of trouble.

[mudhole]

ya, my roof is at 210 degrees (azmuth), which should help with our late afternoon summer rates.

[Ampster]

Go to solarpaneltilt.com for a thorough treatment of solar PV panel tilt angles....

Interesting article that includes TOU pricing to suggest that a slight westward orientation would optimize revenue in some cases. Your mileage may vary.

[solarix]

Go to solarpaneltilt.com for a thorough treatment of solar PV panel tilt angles....

[J.P.M.]

Good points. I stand corrected. Thanks

You're welcome.

[SunEagle]

Better than close to horizontal maybe, but the above statement may be misinterpreted as saying the optimum winter tilt is at latitude. It usually is not, at least outside of the tropics.

Tilt at latitude or close to it is often the best for total annual array output.
For mid and higher latitudes, for the same array, tilt at latitude will indeed give greater winter collection than close(r) to a horizontal tilt angle.
However, tilts greater than latitude usually produce more output in the winter than tilts at latitude.

To say that the greatest (better ?) winter collection is when the tilt angle of an array is at latitude is usually not true or correct for most applications. That optimum tilt (to maximize winter production) is usually closer to latitude + 15 degrees or so, or maybe a bit more, particularly for mid to high latitudes above maybe 30 deg. or so.

Good points. I stand corrected. Thanks

[J.P.M.]

It is during the Winter that the angle of the panels work better at the Latitude the array is sitting on.

Better than close to horizontal maybe, but the above statement may be misinterpreted as saying the optimum winter tilt is at latitude. It usually is not, at least outside of the tropics.

Tilt at latitude or close to it is often the best for total annual array output.
For mid and higher latitudes, for the same array, tilt at latitude will indeed give greater winter collection than close(r) to a horizontal tilt angle.
However, tilts greater than latitude usually produce more output in the winter than tilts at latitude.

To say that the greatest (better ?) winter collection is when the tilt angle of an array is at latitude is usually not true or correct for most applications. That optimum tilt (to maximize winter production) is usually closer to latitude + 15 degrees or so, or maybe a bit more, particularly for mid to high latitudes above maybe 30 deg. or so.

[SunEagle]

what a great site!!!,if i leave at 9%, i lose 4% yearly, however my summer months have a higher kw output , weird, i wouldnt have thought that 10 degrees compared to 20 would be greater output.

During the Summer the sun almost works better with near flat panels. It is during the Winter that the angle of the panels work better at the Latitude the array is sitting on.

[mudhole]

I would run the calculations thru PVWatts at both angles. They may have more dirt depreciation at the lower angle but again their estimated losses will be better then what I can provide.

what a great site!!!,if i leave at 9%, i lose 4% yearly, however my summer months have a higher kw output , weird, i wouldnt have thought that 10 degrees compared to 20 would be greater output.

[Ampster]

...........however it does need a visible air gap disconnect at the inverter per the power company.

All that means is one of those switch boxes with a handle instead of a circuit breaker. You probably have that on your bill of materials list.