After Kogan were recently busted by the ACCC, I was curious about their solar panels.

For example, here is a 250W panel:

https://www.kogan.com/au/buy/yestobuy-solraiser-fixed-solar-panel-sp-d-s-250-bk/

Kogan claims a "maximum 24% conversion rate". The dimensions in the photo are 148cm x 67cm. That's an area of 0.992 sq m. So at 24%, that's a 238W panel.

But can we really believe the figure of 24% ? That's the sort of performance we would expect from A grade monocrystalline panels from top manufacturers. Most panels in this class achieve 21%.

I'm also curious as to what Kogan means by "Built-in overcharging protection". Does that refer to the reverse blocking diode?

Here's a "200W" panel:

https://www.kogan.com/au/buy/yestobuy-solraiser-fixed-solar-panel-sp-d-s-200-bk/

The dimensions are 117cm x 51cm. Even at 24% efficiency, that works out to only 143W.

Here's another 250W panel:

https://www.kogan.com/au/buy/vicoffroad-atem-power-250w-12v-mono-solar-panel-kit-caravan-camping-power-battery-charging-home-k-vaspzhi-6h-sun-r2/

This time the efficiency is 23.5% and the dimensions are 1580mmx 808mm. That works out to 300W. Even at 21% efficiency, the output would be 268W.

So that's potentially a 300W panel for $210.

Another 200W panel:

https://www.kogan.com/au/buy/vicoffroad-atem-power-12v-200w-mono-solar-panel-kit-caravan-camping-power-battery-home-charging-vaspzhi-3h-sun-r2/

Doing the calculations we get a rating of 232W (1476mm × 670mm x 23.5%). So once again this looks like a good deal.

At face value it would appear that Kogan's ATEM POWER panels are conservatively rated, assuming the efficiency is as stated. OTOH, the Solraiser products are overrated and should be approached with caution.