12V Solar Panel Repair advice need it

[4Kyle]

I have 4 units 150W each flexible solar panels, each is 36 cells. I have tested panels one by one, as well in series and parallel connection. I have used two different MPPT controllers, and I have test with a grid tie controller as well. I have Voc about 20(+) V per panel, but I cannot reach more that 40 t0 45 Watts per panel.
Please advice any fix!

 

[snoobler]

Until the recent introduction of ETFE coated flexible panels, the life expectancy of flexible panels is very poor. Long term reliability has yet to be established, but Renogy and other panel vendors have started offering 5 year warranties on flexible panels.

Have you confirmed their Isc?

 

[4Kyle]

Hi snoobler,
Thanks for your reply. These are new solar panels. I have a videos with all my multimeter readings- V/ I at open/ short circuit as well battery charge connection (+) load to optimize performance.... as I stated, panels are new and I am having hard time to realize what could be wrong!?

 

[Forbisher]

Hi snoobler,
Thanks for your reply. These are new solar panels. I have a videos with all my multimeter readings- V/ I at open/ short circuit as well battery charge connection (+) load to optimize performance.... as I stated, panels are new and I am having hard time to realize what could be wrong!?

They are probably only 100 watt panels and not 150 watts.
What was the price per panel?
I count 18 cells. 3 x 6.

 

[SolarQueen]

What are the amps? Did you try changing the angle to make sure it is perpendicular with the sun? Angle will make a huge difference in amps. Tilt them about even with your latitude.

 

[snoobler]

Hi snoobler,
Thanks for your reply. These are new solar panels. I have a videos with all my multimeter readings- V/ I at open/ short circuit as well battery charge connection (+) load to optimize performance.... as I stated, panels are new and I am having hard time to realize what could be wrong!?

Did you buy them from Wish? "Wish" should be renamed, "Lies."

Put a tape measure or ruler on them and provide the length and width across the CELLS, not to the edges.

Panels will only get close to rated output when perpendicular to the sun at high noon.

Please provide:
Length across cells:
Width across cells:
Voc, spec:
Voc, measured:
Isc, spec:
Isc, measured:

 

[Forbisher]

I have 4 units 150W each flexible solar panels, each is 36 cells. I have tested panels one by one, as well in series and parallel connection. I have used two different MPPT controllers, and I have test with a grid tie controller as well. I have Voc about 20(+) V per panel, but I cannot reach more that 40 t0 45 Watts per panel.
Please advice any fix!

This is a 60 watt panel.

 

[Opusdei]

Unlike the rigid panel, I am a little concerned of the junction box near the end of the flexible solar panels. Shading and current crowding as well as dust buildup could affect the performance negatively.

 

[snoobler]

Unlike the rigid panel, I am a little concerned of the junction box near the end of the flexible solar panels. Shading and current crowding as well as dust buildup could affect the performance negatively.

That's typical of flexible panels.

 

[Opusdei]

This is a 60 watt panel.

View attachment 23632

That's right. This is 5 busbar mono panel from Rich Solar. I suspect that is the case for @4Kyle

 

[4Kyle]

Did you buy them from Wish? "Wish" should be renamed, "Lies."

Put a tape measure or ruler on them and provide the length and width across the CELLS, not to the edges.

Panels will only get close to rated output when perpendicular to the sun at high noon.

Please provide: (Answers in green)
Length across cells: 157mm
Width across cells: 130 mm
Voc, spec: 22.3V
Voc, measured: Panel1=21.15V; P2=20.14V; P3=21.15V; P4=20.77V
Isc, spec: 3.63A
Isc, measured: Panel1=3.072A; P2=3.01A; P3=3.13A; P4=3.10A

I am using Solar Tilt APP for best angle calculation today, so I did set exactly at angle= 44.5. All readings are taken at 12:20 PM today. However, when I am connect panels to the grid, I have about 40W per panel (see attached picture)!? I have similar power extraction on OFF grid system as well!? Please advice!!!

 

[4Kyle]

I am using Solar Tilt APP for best angle calculation today, so I did set exactly at angle= 44.5. All readings are taken at 12:20 PM today. However, when I am connect panels to the grid, I have about 40W per panel (see attached picture)!? I have similar power extraction on OFF grid system as well!? Please advice!!!

 

[snoobler]

@MBR called it.

The panel specs with a Isc of 3.6A confirms it, 17V * 3.5 = about 60W. Even using the Voc and Isc (which gives you higher than actual power), you know they're not more than 22 * 3.6=79.2W

Each panel has 0.36m^2 worth of cells. At 17% efficiency, each panel is about 60W based on your per-cell measurements.

You got ripped off.

40-45W on a 60W panel may be pretty good for the circumstances.

Since it looks like you're trying to use a cheap grid-tie inverter, you can't be confident in any of your measurements, but 1.47A @ 120V = 176.4W, which is pretty good for 4X 60W panels.

What's the MPPT voltage range on your inverter?

 

[Forbisher]

I am using Solar Tilt APP for best angle calculation today, so I did set exactly at angle= 44.5. All readings are taken at 12:20 PM today. However, when I am connect panels to the grid, I have about 40W per panel (see attached picture)!? I have similar power extraction on OFF grid system as well!? Please advice!!!

Where did you buy the panels and how much did you pay?
A decent 150 watt panel would be at least $150
Was the selling pic the same as what you got? They are not 36 cells, only 3 x 6 = 18

Actually I found 100 watt flex panels like that for about $80 each when you order three.

 

[4Kyle]

@MBR called it.

The panel specs with a Isc of 3.6A confirms it, 17V * 3.5 = about 60W. Even using the Voc and Isc (which gives you higher than actual power), you know they're not more than 22 * 3.6=79.2W

Each panel has 0.36m^2 worth of cells. At 17% efficiency, each panel is about 60W based on your per-cell measurements.

You got ripped off.

40-45W on a 60W panel may be pretty good for the circumstances.

Since it looks like you're trying to use a cheap grid-tie inverter, you can't be confident in any of your measurements, but 1.47A @ 120V = 176.4W, which is pretty good for 4X 60W panels.

What's the MPPT voltage range on your inverter?

Thanks for your prompt reply. All details are very important to me.

If I can ask, were from is 17V coming in your calculation?

Yes, you are correct... initially I was ripped off, but I submitted video with my tests to the ebay sealer and I received 50% my money back (the original price was $73 per panel). So, I decide to keep these panels for testing- I will build solar tracker.

Wat grid tie inverter would you recommend?

Appreciate your help, as well opinions on all of the other participants in the conversation!

 

[snoobler]

A panel with 20-22Voc will have a Vmp around 17-18V. The Imp will be a little lower then Isc. You can simply multiply Vmp by Imp and it should be the panel rating.

$37 per panel? Sweet.

A solar tracker MAY improve total yield by 30-40% (can vary more depending on location). A solar tracker is almost always WAY more expensive than just buying 40% more panels.

I don't recommend a grid-tie inverter. It's very likely that it's not permitted in your area. While I actually have 1000W and 300W versions that I use it for a very specialized purpose. I would not use it to try and back feed PV power to the grid even though that's the intent. Note that you should make sure that any unit you buy supports "islanding" as you don't want it back feeding to the grid when the grid is down. You could kill a lineman working on what they think is an un-energized line. You should test that it functions by turning the breaker off on that circuit and confirming it shuts down.

 

[4Kyle]

Thanks for your reply.
I will definitely test if "islanding" works.
I will greatly appreciate if you can provide a link to your inverter.

Thanks in advance!

 

[snoobler]

There are many version of it on Amazon, 1000W with operation down to 10.8V or so. Around $120.

 

[4Kyle]

Thanks