Solar Panel Categories, A vs B

[Dawie]

Hello All

I am in the process of researching/sizing/costing a home solar configuration.  A supplier quoted me on a configuration including Sunpower 320W E20 panels, costly but from what I've read these are quality panels.  Another vendor can supply the same panels at a significantly better price, the product details clearly state that these are Category B panels.  I've asked about the warranty and they confirmed that the full manufacturer warranty (25y) still applies.

Based on info from Martin's videos my understanding is that Category B panels perform as well as Category A panels.  Any pitfalls I should be aware of here?  The difference in price is VERY tempting, in the region of 20%.

Please let me know your opinions.

Dawie

[birrbert]

What did the seller tell you about the difference between the two panels? It would be interesting to know what they have to say about this issue.

After a quick Google search I found these articles:
- Grade A, B, C, and D Solar Modules
- What are the differences between A, B, C Grade solar cells?

[Dawie]

Thanks for the feedback Birrbert

The quotes are from two different vendors.

I eventually spoke to our local Sunpower agent/distributor in  Cape Town and was told that their B grade panels have slight discoloration among the different cells, their performance is the same as A grade and the same 25y warranty applies.  There is no defect which could manifest over time to affect the performance.  So basically its an issues of aesthetics only.

The B grade panels end up costing 26% less than the A grade panels although I think the A grades have been marked up by 10% recently and the B grades are still previous stock.

Dawie

[birrbert]

As far as I understand you'll be fine with grade B solar panels if the vendor has a good reputation, has been around for several years and is trustworthy regarding the efficiency of the panels. Get back to us with more info or photos about your solar config.

[Dawie]

18 Sunpower 327W panels installed along with a SMA Sunny Mini Central 8kW Inverter.  Works very well.  Have not had time to pull detailed stats from the inverter yet but the highest output I've seen it generating was around 5.4kW on a nice sunny morning and about 32kWH on a good day.

Some pics of the panels before and after the installation.  I could see no difference in the color of the cells, only one or two scratches on the black paint of some of the frames.

Many thanks to Axel and his team from Ilaanga Energy in Midrand who did the installation.

Planning to add the battery backup fairly soon.

[birrbert]

Wow! They cover quite a large area. Congrats!

[MJLorton]

Hello Dawie,

Thanks very much for your post. I've not had first hand experience of grade B solar panels so it will be interesting to see / hear if you have any issues in the future.

I'm keen to hear about your battery backup system once you have it installed.

Dare I ask...what are you doing with the excess power when you have it....do you have a workable solution or able to push back to Eskom for "credit"?

Cheers,
Martin.

[Dawie]

Excess power is fed back to the grid and the meter that is currently installed runs in reverse when consumption is less than solar production.  That is the only "credit" I can hope for at the moment due to the fact that the municipality (Tshwane) currently has no mechanisms in place to compensate one for power fed back to the grid.

Regards
Dawie