25 year solar panel review

Makers · February 2019

Hey People!

Wanted to post review on 26 year old panels. (SIEMANS M75. 48W) I have 24 of them on a 24v nominal system wired for 48v. My CC says this will give me maximum efficiency. Rated new at STC I would have 1152W of panels.

4 panels wired in series x 6

8 panels wired in parallel x 3

3 strings into combiner box

STC: (63.6V X 18.12A)

My CC is (EPSOLAR 4210 40A) can charge at 1040w and maximum input is around 1500w

I live in Hawaii so I am blessed as far as being close to STC for solar panels temperature wise.

I havent been able to see what these panels have been capable of due to hitting absorb at around 10:30 in the morning. Today we had some morning storms and the weather cleared up very nicely so I could see the panels maximum production around 11:30am.

The maximum I usually see is around 700w before absorb.

I also still have the original manual for the panels aswell, so I will post some pictures

This was at 23C temperature

Just wanted to share, if anybody was interested.

Thanks all have a great day

littleharbor2 · February 2019

How are your panels oriented to the sun at solar noon? Just asking to see if they're pitched correctly at this time of year.

I have a really cool app called Solar Tilt. It will give you the perfect angle for any day of the year and at any latitude. It will default automatically for your location and day. Simple to set it for any day, anywhere. Very easy to use and it also has a tilt gauge function that allows you to simply put your phone on edge, on the face of the panel ant it seems to be very accurate.

Makers · February 2019

https://forum.solar-electric.com/discussion/comment/395366#Comment_395366

They are on 22 degree slope. Facing 10 Degrees towards the west from due south,

littleharbor2 · February 2019

21 degrees latitude, Maui optimum tilt today would be 34.1 degrees. You would see higher current and overall wattage with this angle. Of course if you have a fixed tilt you are right about where you would want to be for best year round output.