Sunpower 450w panels OK?

Saw these panels on sale at Signature Solar. Aren’t Sunpower panels supposed to be good? Thought they seemed pretty cheap at $180 each.

Any known issues with them?

Those are large commercial panels so be sure you understand the size panel you are buying. Also the warranty on those panels will most likely not be honored, per the warring on sig solars site: "Warranty is valid only if installed by certified SunPower solar installer". I was unable to find the warranty policy document for these model panels to confirm or deny this, so I would assume they have no warranty.

If you are buying pallet quantities of panels also check out: https://inxeption.com/flash-sales/energy

This is a project for a stepvan build I’m working on, so I only need 5 panels and will sell the 5 others or keep for another project down the road.

Yeah I realize these are big panels. I’ve been buying panels off Craigslist from a local installer, but these Signature Solar prices are lower than his even after tax and shipping and his also have no warranty.

Are Sunpower panels still top tier, or am I behind the times or mistaken?

Cardude said:

This is a project for a stepvan build I’m working on, so I only need 5 panels and will sell the 5 others or keep for another project down the road.

Yeah I realize these are big panels. I’ve been buying panels off Craigslist from a local installer, but these Signature Solar prices are lower than his even after tax and shipping and his also have no warranty.

Are Sunpower panels still top tier, or am I behind the times or mistaken?

Click to expand...

Have you decided to buy these panels? I am on the same boat

I did not end up getting them. Found some panels locally.

Not sure if this is still true for their new modules, but when I checked on some older used Sunpowers, my installer friend told me they had issues with charge building up and reducing power, and for that reason they had to be installed with + grounded. If this is still true of their current panels, then it may cause issues with some CC's and other devices (rapid shutdown, etc). I passed on the used ones for this reason...

That probably referred to "PID", Potential Induced Degradation, where ions driven into the cells affected them.
Some cells are P-type silicon with N doped layer, others are N-type with P doped (I can't remember which is conventional and which SunPower uses). SunPower cells were supposed to be of a type that lasted longer in the sun, but when configured with negative terminal grounded the more positive biased panels degraded.

SunPower fixed that with material changes (glass and epoxy), and the data sheet for the panels above says, "PID Test 1500 V: IEC 62804". Some other brands still suffer from PID. Most grid-tie inverters today are transformerless, with PV string floating half biased above ground and half biased below, so subject to PID if not resistant.

I have smaller 327w panels of the E20 series. Fine so far, but of course I don't have long-term data.