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Results of testing new panels from Santan Solar

RollingThunder

New Member
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Feb 24, 2021
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Hello everyone,
I just received my panels, 250w T series snail trails, from Santan Solar. The package was undamaged, and I tested the panels immediately after unpacking. It was between 11am-noon, sunny, hot, about 100f degrees. I tested one panel at a time, laid flat on some unistrut, on a concrete pad, so each panel was set on the exact same place, one swapped out with the next as quickly as I could do so. I tested each parameter for only 10-15 seconds before moving on to the next due to the very hot conditions.

According to the sticker:
The panel model is ss250p-60.
The VOC is 37.6v
The IMP is 8.27.

Test results of all 9 panels:
1. 34.4v,8.5a (292w)
2. 34.4, 8.49 (292)
3. 35, 8.55 (299)
4. 34.7, 8.6 (298)
5. 34.5, 8.55 (295)
6. 35, 8.6 (301)
7. 34.3, 8.7 (298)
8. 34.9, 8.69 (303)
9. 34.5, 8.73 (301)

These are my first solar panels, and the numbers seem good to me, can others validate that these are good to go?

Thanks!
 
I.E.: "1. 34.4v,8.5a (292w)" Getting 292W from used 250W panel?
That cannot be right.
How did you go about testing the those panel?
Are you multiplying the open circuit measured Voltage to the measured Ishorted circuit?
What is the Vmp spec of the panel? What is the Isc spec?
Vmp x Imp = Panel power
 
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Hi Bud, used a multimeter and did the volts, then the amps, and that's what it gave me, and as you can see I just multiplied the numbers together.
There was nothing else involved, just the panel, the multimeter, and the sun.
If that's not how it's done, let me know what to do differently.

I'm aware that the VMP will be lower than the VOC. Perhaps I should not have added the multiplied number and just posted the VOC and IMP. Ignore the watts, and tell me if you would consider the numbers posted above acceptable.

To me, the amps seem ok, but I was hoping the volts would be closer to 37 than 35, but is that generally considered acceptable?

Here are all the specs from the label, unfortunately they don't include the abbreviations.

Maximum Power - W - 250
Open-Circuit Voltage - V - 37.6
Voltage at Pmax - V - 30.3
Short-Circuit Current - A - 8.85
Current at Pmax - A - 8.27
Max System Voltage - V - 600
Fuse Rating - A 15A
 
I have the exact same panels. Mine VOC test roughly 35v and ISC of 6.2a. Your panels are doing leaps and bounds better than mine.

Actual wattage output under a load I cannot get more than 190 watts though.
 
I had a good experience with SanTan solar - I was a bit hesitant to try used panels but the price is too good to pass up. I ordered 10 of the 250W silver frame (Trina) panels at $50 each plus about $250 total shipping with delivery to the local Central freight terminal. The packing was good, and all panels survived the shipment undamaged. I've been testing them all using a Victron 100/30 MPPT; all produce between about 190-200W; my control panel set of new 4x100W Renogy panels produces roughly 300W today, so the output of the SanTan panels certainly meets expectations. They are in good shape - clearly used with a few dings and discolorations but completely functional.
 
We bought panels last fall, as well as some recently (the same 250w panels you have except not snail trail). We found that the panel voltage was many times 37v and above during the winter, but now, in the heat, 35v is the best they will show open circuit. The panels that were making 230-280 watts in the dead of winter are doing around 200 watts, now. Panel temperature is the best explanation I have.
 
Yes, I measured the panel temperature at about 125F - this should drop the efficiency by around 10-15% from 25C. Panels I bought weren’t the snail trail ones by the way, I bought them just before the price increase, they are the standard Trina silver frame panels. The only downside to these panels so far is the lack of bypass diodes.
 
Bumping an old thread. I purchased 2 pallets of these panels in 2019 or 2020 (can't remember)

Any way they have been in storage this whole time, outside in the rain, moved from FL to TN on an open trailer.

I did not have much hope for them now that I am getting my act together. I decided to test some, happy with the results so far :)

20230419_145720.jpg
20230419_150125.jpg
 
Looks like you hit the jackpot.

But in regards to what the label says, Santan buys used and decomissioned panels. They are re-labeled by Santan. That 250W rating is the minimum of what Santan tested it to be. The original label is gone and there's no telling what it was before. I believe, based on the size of the panels, they are probably 300W or 350W panels. I bought a pallet full of the same panels a year ago.
 
Bumping an old thread. I purchased 2 pallets of these panels in 2019 or 2020 (can't remember)

Any way they have been in storage this whole time, outside in the rain, moved from FL to TN on an open trailer.

I did not have much hope for them now that I am getting my act together. I decided to test some, happy with the results so far :)

View attachment 145557
View attachment 145558
What instrument is that you are using for testing?
 
Looks like you hit the jackpot.

But in regards to what the label says, Santan buys used and decomissioned panels. They are re-labeled by Santan. That 250W rating is the minimum of what Santan tested it to be. The original label is gone and there's no telling what it was before. I believe, based on the size of the panels, they are probably 300W or 350W panels. I bought a pallet full of the same panels a year ago.
I know they are Trina Solar panels and yeah I purchased them as used, I think it was $40 a panel at the time.

What instrument is that you are using for testing?
My daughter was able to get me this when she was in the PhD program at Texas A&M. Some crazy good deal (like 80% off it was a demo) otherwise this tester is usually out of reach of us mere mortals :) It was also cheaper 4 years ago
 
Looks like you hit the jackpot.

But in regards to what the label says, Santan buys used and decomissioned panels. They are re-labeled by Santan. That 250W rating is the minimum of what Santan tested it to be. The original label is gone and there's no telling what it was before. I believe, based on the size of the panels, they are probably 300W or 350W panels. I bought a pallet full of the same panels a year ago.
Definitely not 300 or 350w panels. Under Santan's label is an original Trina tag/sticker. They are 250w Trina Panels for sure.
 
Nice thing is it comes with a reference cell, so when you test the panels you get accurate results no matter what the sunlight brightness is
20230419_165334.jpg
 
Definitely not 300 or 350w panels. Under Santan's label is an original Trina tag/sticker. They are 250w Trina Panels for sure.
I agree I think the are 250's, I didn't set the reference cell up perfectly so my reading might be a little off.
 
I agree I think the are 250's, I didn't set the reference cell up perfectly so my reading might be a little off.
You can also just google Trina 250w panel data sheet and it comes up with the exact panel. They are 100%.
 
I know they are Trina Solar panels and yeah I purchased them as used, I think it was $40 a panel at the time.


My daughter was able to get me this when she was in the PhD program at Texas A&M. Some crazy good deal (like 80% off it was a demo) otherwise this tester is usually out of reach of us mere mortals :) It was also cheaper 4 years ago
Yikes! Cheapest I saw was like $3800.

Nice gear though..
 
Yikes! Cheapest I saw was like $3800.

Nice gear though..
I like it but it has limited value for a homeowner like me. The price was to good to pass up and I am a certified member of TEA*


*Test Equipment Anonymous (for people who have a lot of GAS**)
** Gear Acquisition Syndrome
 
Curve tracers are the gold standard for testing, have used the before on full arrays.

On Santan panels, mine were getting 205 to 225 watts AC using Enphase M215's in Florida heat ( panels are typically 125-135F ). Nothing is lower cost and there is no technical reason the panels won't last for decades. I sold them off at cost for Santan perc half cells for $90 a panel ( 395W ) and they have been running 2+ years without a single issue and stellar performance.
 
Had a little spare cash and wanted to put my toes into the solar water and those Santan used panels are a no brainer. Bought 25 240 watt used panels mostly with cracks in the coating underneath the panels and they are certainly performing well. Getting motre than 4 kilowatts in the middle of the day with still 2 months to go to summer solstice. My six batteries are fully charged an hour before mid day so I am quite happy with my $40 a piece panels. The location is close to 40 degrees North. What we really need is $40 batteries!
 
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