Upgraded to 4 stars. Right after publishing the original review, we had a nice sunny day that allowed for comparing the Growatt to a more efficient panel (for its active solar area based on STC standard test conditions) mentioned in the review . The Growatt pushed out 145 watts where the "more efficient" panel was producing only 122 watts under the same conditions. The difference seemed to be related to the temperature of the solar cells. The Growatt was running 10 to 15 degrees cooler in all 4 panels compared to the competitive panel. I don't know why that would be.
STC pegs the temperature of the panel under test at 77F (25C) and the panel temps today varied between 115 degrees to 122 in any of the 4 panels in the Growatt. The "more efficient" panel was running 10 to 15 degrees above that. Can't be sure that was the reason, but the watts being produced tells the story.
So there you have it. Panel specs based on STC should be taken with a grain of salt maybe? What matters is what happens in the real operating conditions and makes these comparisons important. In spite of some of the negatives mentioned about the Growatt, I think this power difference is worth the upgrade.
Lick your fingers for grip, no grab handle when the panel is out of the case.
Wide and sturdy kickstands, ETFE construction with oxford fabric backing with no handles on the panel (only handles on carrying case). Panel edges are sharp and with the oxford cloth backing can work like a saw against skin. Cut skin on a knuckle which was kind of a nuisance because it bugged me for a few days. I have 2 other 200w foldables and never ran across that because the panels have integrated handles.
MC4 connectivity only. Wires are tie wrapped so that they don't dangle loosely. I liked that idea and will leave them that way.
The carrying case is a curious item. it has no pocket our pouch for extra adapters. One side of the case has a rigid reinforcement while the other side flops loosely, so it will stand up with no panel in it. The panel seems heavy and is a little cumbersome to handle out of its pouch. Set up it is sturdy, but with only 3 kickstands for 4 panels, but looks like something is "missing"!
For its active solar area, its power output is slightly lower than 2 other brands of this type of foldable panel based on manufacturer's Volts @ Pmax and Amps @@ Pmax. Keep in mind that power is measured under standard test conditions (STC) and the power produced is what is spec'd. The other 2 panels produced 199.98 and 198 watts with the Growatt 200 coming in at 189.62.
Power figures in watts per sq in of active solar area are 0.125, .122 and .118 (Growatt 200), with a total active area in sq inches of 1594.91, 1624.42 and 1609.88 (Growatt). So the Growatt 200 produced less power per sq in and is slightly less efficient. An after the fact review of efficiency ratings showed the Growatt has an asserted efficiency rate of 22%. Of the other 2, one claims 23.5% and the other 23%). Interestingly again, the 1594.9 (smallest active area) produced more power per sq in. If you guessed that's the one at 23.5% efficiency, you'd be right.
Didn't have chance to do a comparison under good solar conditions. The STCs tell the story for now.
On the plus side
--the MC4 that are stowed and an easy connection.
--solid ETFE construction with oxford fabric backing
--easy MC4 release/disconnect compared to typical barbed connectors.
--Magnetically secured kickstands provide easy release compared to velcro
On the down side,
--no other included connectivity (but that's no surprise as listing mentions ONLY MC4)
--sharp edges can cut with saw like action linked to
--only the carrying case with a grip.
--carrying case has no pouch or pockets for extra cables/manual
In summary, less efficiency, at $349 a higher price, harder to handle with sharp edges, this one is teetering on the border between a high 3 or low 4. More to follow after comparison testing under better solar conditions.