Solar Test Data

[alain-chuzel]

I had an opportunity to obtain outdoor current vs voltage curves (IV curves) of Maxeon Gen 3 and Gen 7 solar cells in a “side by side” test. While clearly more efficient, the Gen 7 cells aren’t the “barn burners” I was hoping for. Perhaps Maxeon is still improving on how the Gen 7 cells are being made.

Here’s a quick vid I made of the results. Note I actually tested 4 series connected cells of each of Gen 3 and Gen 7. https://www.youtube.com/watch?v=T0o2puBRxLo

[Kamakiri]

It’s still a nice bump in output. Thanks for sharing. Did you notice or test for relative thermal loss? Now that it’s Fall, I’d have a tough time trying to casually test anything into the 150°F range.

[john-malcom]

By the way good technical post reflecting some focused research. 👍

[Kamakiri]

Solar research at the hobbyist level is what brought me to Aptera in the first place! Sunpower/Maxeon cells were already my preference for value, performance and reliability. It was exiting to find them independently selected for use in an on-board vehicle application.

[john-malcom]

👍 ! So we have another go to person for the solar cell technology. A good technology niche for Aptera commenting. Appreciate you overcoming your reluctance to share your background. .

• This reply was modified 2 months ago by  John Malcom.
• This reply was modified 2 months ago by  John Malcom.

[Kamakiri]

Thanks for the comment, but my expertise regarding solar is limited to my particular uses for charging and maintaining low voltage systems. It’s how I power everything between my shop and office. Hardly my ‘background’ though, in any real sense of the word. But does give me some insight into and appreciation for the string arrangement for our beloved Aptera. 🙂

[alain-chuzel]

Did you notice or
test for relative thermal loss?

I’m afraid I don’t 100% understand your question. Both sets of 4 series cells were mounted to the same board (within inches of each other) and exposed to the same environmental conditions. In principle all 8 cells were at about the same temperature and I didn’t measure the temperature. The idea behind the test was to just get relative IV data between the two cell types under identical (albeit random) conditions.

[Kamakiri]

Sorry about being unclear…Do you have any plans to test or compare at higher temps? Nice to see the new cells exceeding 3.6W in test conditions.

[alain-chuzel]

Not really. I doubt the temperature coefficient differences between Gen 3 and Gen 7 would change in any appreciable way. Don’t read too much into the absolute wattage values. There were slow moving intermittent clouds (very white) and “edge of cloud” effect could easily boost solar irradiance by many percentage points over “1 sun” (1000 w/m^2) for several seconds. For example, check out the following set of IV curves for the same sets of Gen 3 and Gen 7 cells. I deliberately took these as I noticed large white cloud slowly approaching the sun. A full 23% MORE irradiance hitting the cells in this sweep than in the sweep shown in the YouTube vid above.

[Kamakiri]

Understood, and thanks for the clarifications! It is interesting how cloud refracted light can make very usable power…even in ‘full’ shade. It’ll be fun to watch what people will learn just observing their Aptera’s solar charging display.

[john-malcom]

Thanks for this technical data on the solar cells comparison testing! As I recall from some of your previous posts, this is an area of your expertise. I remember your testing and comments in the previous form on the cells. It is good to have such an expert available to show reality vs. hype. I am surprised that the curves are so close. Hopefully more improvement coming before needed/commercially available as a commodity.

• This reply was modified 2 months ago by  John Malcom. Reason: update content
• This reply was modified 2 months ago by  Gabriel Kemeny.

[alain-chuzel]

👍