• Have you tried out dark mode?! Scroll to the bottom of any page to find a sun or moon icon to turn dark mode on or off!

diy solar

diy solar

Panelling to maximize hours of sun, not amount of sun.

Æon

New Member
Joined
Jan 15, 2025
Messages
7
Location
Honduras
OK so, I understand that in most cases, you want to have your panels facing true south or north, depending on the hemisphere, and at the correct angle based on your elevation...

But what if you have limited battery power, and you're trying to maximize the hours you get sunlight for?

I have a small system just to power the small loads in my house - fans, lights, Starlink, fridge, and occasionally kitchen gadgets. Usually this sits at 300-500w during the day, and a bit lower at night. I have 7kWh of battery to get me through the dark hours. I live in the caribbean, where sun is ample, and I'm able to plug 3 separate arrays into my system. Would it be a terrible idea to have 2-3 large panels angled true south at 18 degrees, or whatever it is, and one big panel pointed a bit more west to get as much sun as possible from the sunset? Maybe even a little 200w panel pointed at the sunrise to get cooking as early as possible.

I mean, I'm probably going to do it anyway, just to play with the math and bother my wife with the results. Just wondering if anyone else has done this.
 
Put half your panels facing SE and the other half facing SW. You don't need any facing S because of the overlap in production between the 2 sets.
This.

SE and SW arrays is always a great choice with limited battery capacity. This also prevents the need of larger SCC's because your peak PV will be lower.

At the end of the day, you will not capture as much potential PV if the entire array were South facing, but if you have limited battery capacity, that potential would have been lost anyways.
 
OK awesome. Y'all are talking about this like it's an established thing that people do. I feel less foolish now!
 
Another alternative is to have a rotating array, which is not hard to make. Here's some pics of a rotating array that can hold three large high-voltage residential panels, maybe up to 1kW of panels. I first sank a 8cm diameter steel pipe 1 meter into concrete. I slipped a capped 10cm steel pipe over the one cast in concrete. The hinged array is welded onto the top of the capped pipe. Using the lower horizontal spars, I can also adjust for seasonal declination change, in addition to changing the daily azimuth. Frame is made out of unistruts. Note: The arrays are NOT motorized. The sun is hillbilly tracked by hand.
 

Attachments

  • 024.JPG
    024.JPG
    315.8 KB · Views: 6
  • 025.JPG
    025.JPG
    460.2 KB · Views: 6
  • 032.JPG
    032.JPG
    487.7 KB · Views: 6
Another alternative is to have a rotating array, which is not hard to make. Here's some pics of a rotating array that can hold three large high-voltage residential panels, maybe up to 1kW of panels. I first sank a 8cm diameter steel pipe 1 meter into concrete. I slipped a capped 10cm steel pipe over the one cast in concrete. The hinged array is welded onto the top of the capped pipe. Using the lower horizontal spars, I can also adjust for seasonal declination change, in addition to changing the daily azimuth. Frame is made out of unistruts. Note: The arrays are NOT motorized. The sun is hillbilly tracked by hand.
Those are called top of pole mounts. I also did that so I didn't even have to decide which direction to point the arrays. I point them in different directions in the summer to maximize the time I am getting PV power, not maximum kWh per day:

IMG_0526.JPG
 
OK so, I understand that in most cases, you want to have your panels facing true south or north, depending on the hemisphere, and at the correct angle based on your elevation...

But what if you have limited battery power, and you're trying to maximize the hours you get sunlight for?

I have a small system just to power the small loads in my house - fans, lights, Starlink, fridge, and occasionally kitchen gadgets. Usually this sits at 300-500w during the day, and a bit lower at night. I have 7kWh of battery to get me through the dark hours. I live in the caribbean, where sun is ample, and I'm able to plug 3 separate arrays into my system. Would it be a terrible idea to have 2-3 large panels angled true south at 18 degrees, or whatever it is, and one big panel pointed a bit more west to get as much sun as possible from the sunset? Maybe even a little 200w panel pointed at the sunrise to get cooking as early as possible.

I mean, I'm probably going to do it anyway, just to play with the math and bother my wife with the results. Just wondering if anyone else has done this.
If you’re going to add some panels to face east and another panel to face west, I’d recommend another MPPT for each of these setups. The MPPT need not match. Its best if they can be the same brand so they can network together, but that’s not a show stopper.

My house has 4 MPPTs, each with a 100 amp 48 volt (~5 kW) max output and 5 kW max array. 2 X 5 kW face south, a 3 kW array faces east which has been great for the morning sun, and a 4 kW array faces north which sucks in the winter but will really help come summer time. The house has gabled roofs which is not optimal for the bigger arrays that can be set with 8 or 9 panels in series for up for 600 volts.

I do something similar for the RV with 3 MPPTs one of which is a 100 volt 50 amp MPPT, and the other two are 100 volt 30 amp MPPTs and the biggest producer being the MPPT with the portable ground mount panels.
 

diy solar

diy solar
Back
Top