Did I Get Ripped Off?

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
I purchased 30 used Sunpower E-Series Commercial Solar Panels E20-435-COM from ebay and they are advertisted to be working at 98% of out of the box capacity. However, when I tested several of them today in clear, direct sunlight, I'm only getting 80-85% of the rated 435w output. Did I get ripped off?

At first, I was shocked and very disappointed at such a low output. I paid up for these panel compared to other offerings on eBay and considering the wording of the ad, I thought was expecting more. Now to be fair, on a percentage basis, they did do slightly better than my existing 265w panels, but I was really expecting over 400 watt in direct sunlight...especially since it was so cold here today (near freezing).

So am I expecting too much from these panels or was I straight up deceived by the seller? Please chime in...

The pictures below show the readings from the charge controller and the position of the sun at the start of the testing. The result got worse the more I tested so that is likely related to the sun moving farther west. I guess I really can't complain since they are outperforming my existing panels. But I was hoping for that 98% claim. Maybe when the sun is higher.
 

Attachments

  • IMG_1436.jpeg
    IMG_1436.jpeg
    275.8 KB · Views: 27
  • IMG_1420.jpeg
    IMG_1420.jpeg
    1.4 MB · Views: 27
  • IMG_1419.jpeg
    IMG_1419.jpeg
    1.9 MB · Views: 26
  • IMG_1416.jpeg
    IMG_1416.jpeg
    567 KB · Views: 27
  • IMG_1435.jpeg
    IMG_1435.jpeg
    344.9 KB · Views: 27
  • IMG_1438.jpeg
    IMG_1438.jpeg
    231.1 KB · Views: 26

RCinFLA

Photon Sorcerer
Joined
Jun 21, 2020
Messages
1,593
If in northern hemisphere, it is winter time with sun only reaching low angles above horizon. Lower to horizon sun means more atmospheric losses.

I highly doubt anyone can measure a 98% of rating output on a panel accurately.
 

sunshine_eggo

Happy Breffast!
Joined
Oct 26, 2021
Messages
3,538
Location
USA
I purchased 30 used Sunpower E-Series Commercial Solar Panels E20-435-COM from ebay and they are advertisted to be working at 98% of out of the box capacity. However, when I tested several of them today in clear, direct sunlight, I'm only getting 80-85% of the rated 435w output. Did I get ripped off?

Probably not.

Have you confirmed that the panels are receiving 1000W/m^w of insolation? If not, you can't make any objective conclusions whatsoever.

Assuming you are in the northern hemisphere by how low the sun is in the sky, you're about 30 days past the WORST solar day in the northern hemisphere (winter solstice).

At first, I was shocked and very disappointed at such a low output. I paid up for these panel compared to other offerings on eBay and considering the wording of the ad, I thought was expecting more. Now to be fair, on a percentage basis, they did do slightly better than my existing 265w panels, but I was really expecting over 400 watt in direct sunlight...especially since it was so cold here today (near freezing).

Direct sunlight in Winter has inherently less total energy available.

So am I expecting too much from these panels or was I straight up deceived by the seller? Please chime in...

Blatantly.

The pictures below show the readings from the charge controller and the position of the sun at the start of the testing. The result got worse the more I tested so that is likely related to the sun moving farther west.

And/Or because the cells were heating from solar and current flow. It might have been freezing, but those cells were warm.

I guess I really can't complain since they are outperforming my existing panels. But I was hoping for that 98% claim. Maybe when the sun is higher.

Maybe around the Summer Solstice.
 
Last edited:

sunshine

Solar Addict
Joined
Apr 24, 2020
Messages
697
I guess I really can't complain since they are outperforming my existing panels. But I was hoping for that 98% claim.
Maybe just a reality check as to the % difference expected between 2nd hand 435w and 2nd hand 265w panels.
80-85% seems ok to me, It would be interesting to know what your 265w panels are getting under the same test.
 

MurphyGuy

It just needs a bigger hammer
Joined
May 20, 2020
Messages
1,428
I purchased 30 used Sunpower E-Series Commercial Solar Panels E20-435-COM from ebay and they are advertisted to be working at 98% of out of the box capacity. However, when I tested several of them today in clear, direct sunlight, I'm only getting 80-85% of the rated 435w output. Did I get ripped off?

At first, I was shocked and very disappointed at such a low output. I paid up for these panel compared to other offerings on eBay and considering the wording of the ad, I thought was expecting more. Now to be fair, on a percentage basis, they did do slightly better than my existing 265w panels, but I was really expecting over 400 watt in direct sunlight...especially since it was so cold here today (near freezing).

So am I expecting too much from these panels or was I straight up deceived by the seller? Please chime in...

The pictures below show the readings from the charge controller and the position of the sun at the start of the testing. The result got worse the more I tested so that is likely related to the sun moving farther west. I guess I really can't complain since they are outperforming my existing panels. But I was hoping for that 98% claim. Maybe when the sun is higher.
I can tell by looking at the picture of your house that 80 to 85% is pretty spot on.. I'm guessing you're somewhere around the middle of the USA in latitude? Maybe Kentucky, Iowa or a bit more south?

When the sun is directly overhead and its 50°F outside, try it again and I bet you get full power.
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
Maybe just a reality check as to the % difference expected between 2nd hand 435w and 2nd hand 265w panels.
80-85% seems ok to me, It would be interesting to know what your 265w panels are getting under the same test.
They were producing around 80%.
 

Attachments

  • IMG_1435.jpeg
    IMG_1435.jpeg
    344.9 KB · Views: 7

Bud Martin

Photon Sorcerer
Joined
Aug 27, 2020
Messages
3,053
So do you see the Power go up if you try to charge the drained battery or with heavy loads running?
The battery is at 58.50V, that battery looks to be full.
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
I can tell by looking at the picture of your house that 80 to 85% is pretty spot on.. I'm guessing you're somewhere around the middle of the USA in latitude? Maybe Kentucky, Iowa or a bit more south?

When the sun is directly overhead and its 50°F outside, try it again and I bet you get full power.
That's not my house. That's next door. See my house below. My idea of a tiny house.

I will be covering that roof with solar panels. I had to raise the building to get that RV under there.
 

Attachments

  • IMG_1130.jpeg
    IMG_1130.jpeg
    777.1 KB · Views: 22
  • 66215218447__F84C51C0-1179-489B-9CB9-1B29CCC2803C.jpeg
    66215218447__F84C51C0-1179-489B-9CB9-1B29CCC2803C.jpeg
    781.6 KB · Views: 19
  • 66215226371__07CD6BAD-9E20-4330-A845-26320ECBEA73.jpeg
    66215226371__07CD6BAD-9E20-4330-A845-26320ECBEA73.jpeg
    856.5 KB · Views: 16
  • 66191570946__B16BEA8E-0159-4921-8DBB-1A4AAE864775.jpeg
    66191570946__B16BEA8E-0159-4921-8DBB-1A4AAE864775.jpeg
    718.8 KB · Views: 16
  • 66215229983__5F81739F-B52D-4673-8DBA-DE8DD08DF1DA.jpeg
    66215229983__5F81739F-B52D-4673-8DBA-DE8DD08DF1DA.jpeg
    854.7 KB · Views: 17
  • 66215228713__B91C1178-91F5-4309-921D-1BF9590E9885.jpeg
    66215228713__B91C1178-91F5-4309-921D-1BF9590E9885.jpeg
    764.1 KB · Views: 22
  • IMG_1049.jpeg
    IMG_1049.jpeg
    1.2 MB · Views: 22
  • IMG_1001.JPG
    IMG_1001.JPG
    101.7 KB · Views: 23
  • IMG_8450.jpeg
    IMG_8450.jpeg
    835.3 KB · Views: 23
Last edited:

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
So do you see the Power go up if you try to charge the drained battery or with heavy loads running?
The battery is at 58.50V, that battery looks to be full.
It still wasn't full. At the end of the day it was only up to 85%.

The voltage will go down if I put a load on it. That installation wasn't under load at all. It had just been charging all day.
 

Bud Martin

Photon Sorcerer
Joined
Aug 27, 2020
Messages
3,053
It still wasn't full. At the end of the day it was only up to 85%.

The voltage will go down if I put a load on it. That installation wasn't under load at all. It had just been charging all day.
According to the Voltage charge 55.20V is 99.50% SOC, 58.40V is 100%. 85% SOC is up there already, as battery getting fuller, the power draw from the panels will drop, that is why I suggest you to turn on heavy loads so it will draw more power from the panels.
So if you turn on heavy loads, you do not see the Wattage goes up? You should see charging current goes up.
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
So if you turn on heavy loads, you do not see the Wattage goes up? You should see charging current goes up.
Not from that set of panels. It was still bulk charging. Hadn’t even made it to absorb. Under paneled. That’s why I’m adding more. That trailer has 2.6k of PV charging 1040ah of batteries. It usually takes 3 days to fully charge those batteries, and that’s with direct sunlight and no loads. The fact that we very seldom get clear skies here and the fact that the trailers are under paneled anyway is the reason I’m adding so many panels. I’m in northwest Louisiana.
 

MurphyGuy

It just needs a bigger hammer
Joined
May 20, 2020
Messages
1,428
That's not my house. That's next door. See my house below. My idea of a tiny house.

I will be covering that roof with solar panels. I had to raise the building to get that RV under there.
My point was that sun is way down low on the horizon and the energy has to pass through a whole lot of atmosphere before it gets to your panels.

No panel will produce full power under those conditions.. so if you're getting 80 to 85, then your panels are probably in great shape.
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
My point was that sun is way down low on the horizon and the energy has to pass through a whole lot of atmosphere before it gets to your panels.

No panel will produce full power under those conditions.. so if you're getting 80 to 85, then your panels are probably in great shape.
Makes sense. Thanks!
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
I did some more testing on those SunPower solar panels, this time in overcast conditions. They are commercial panels and are supposed to be more efficient than conventional panels. Well, I'm sorry to say that they performed no better than my existing Talesun TP660P 265 watt panels. Both the Talesun and the put out 10-12% off their rated power during overcast conditions. These are the conditions I'd hope that the SunPower panels would show their superiority. But nope, that are as mediocre as the Talesuns.

I paid extra for the SunPower panels. $.38 per watt. I could have gotten conventional panels for $.23 per watt, so I paid almost twice as much as I had to. Oh well, you win some and you lose some.

I've attached pictures of my results. I'm too lazy right now to label the images, but you should be about to tell which panels are being tested by the calculations above them. Maybe their performance is why they were uninstalled and sold on ebay.
 

Attachments

  • IMG_1502.PNG
    IMG_1502.PNG
    6.2 MB · Views: 5
  • IMG_1501.PNG
    IMG_1501.PNG
    5.5 MB · Views: 5
  • IMG_1493.jpeg
    IMG_1493.jpeg
    469.6 KB · Views: 5

Bud Martin

Photon Sorcerer
Joined
Aug 27, 2020
Messages
3,053
Picture #2 shows PV 146.3V, 294W.
Picture #3 shows 54.8V, 46W

Are they SunPower readings?
 

sunshine_eggo

Happy Breffast!
Joined
Oct 26, 2021
Messages
3,538
Location
USA
I did some more testing on those SunPower solar panels, this time in overcast conditions. They are commercial panels and are supposed to be more efficient than conventional panels. Well, I'm sorry to say that they performed no better than my existing Talesun TP660P 265 watt panels. Both the Talesun and the put out 10-12% off their rated power during overcast conditions. These are the conditions I'd hope that the SunPower panels would show their superiority. But nope, that are as mediocre as the Talesuns.

Why you would expect them to perform differently? A panel's performance is dictated by the amount of energy falling on its surface and its efficiency. Most panels are around 20% efficient. Even if they are 21% efficient, that's only 5% more efficient than 20%. If the solar conditions are such that they are only getting 10% intensity, the more efficient panel will only yield another 0.1% of rated power.

Mediocre? Those are great results. There is no such thing as magic. Panels can't create energy from nothing. Cloudlight has substantially less energy than sunlight.

I paid extra for the SunPower panels. $.38 per watt. I could have gotten conventional panels for $.23 per watt, so I paid almost twice as much as I had to. Oh well, you win some and you lose some.

Nobody to blame but you. You made the purchase based on hope and assumptions. Guess what? Clouds make for shit solar on ALL panels.

I've attached pictures of my results. I'm too lazy right now to label the images, but you should be about to tell which panels are being tested by the calculations above them. Maybe their performance is why they were uninstalled and sold on ebay.

You have no basis for this claim. It's based on your unrealistic expectations. All evidence presented indicates they are performing as they should. You can't claim shenanigans on the part of others when you have unrealistic expectations.

$0.38/Watt is a great price. Take the win.

And stop taking seductive pictures from your bed! :p

1643172020112.png
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
Why you would expect them to perform differently?
This is why I expected them to perform better. SunPower claims 20% effiency. Talesun only claims 16%. Yet they perform the same.

Oh, and if you think that picture is seductive, you are playing for the wrong team buddy. So keep your fantasies to yourself.

1643173768673.png
 

Ralo

Solar Enthusiast
Joined
Jan 12, 2020
Messages
187
Picture #2 shows PV 146.3V, 294W.
Picture #3 shows 54.8V, 46W

Are they SunPower readings?
Picture 1502 is a single 435w SunPower panel. Picture 1501 is 10 - 265w Talesun panels.
 
Last edited:
Top