Solar and Inverter Warehouse in here in Petoorsdorp. I recently bought from them. JA or Jinko.
Many places that does this I see all over Facebook.
I got Canadian Solar about a month ago, at about R4.15 per watt.
One reason I would actually consider (strongly) older panels like in that ad, would be to match older equipment. For example, I have an older ABB PV-inverter that is so limited on the maximum PV current, that I cannot really fit anything above 425W to it. The new 650W panels make so much current that I cannot use them with the Solis I bought on a whim a few months ago. On top of that, a lot of equipment really wants you to push the voltage up to get full power (not the current), which actually incentivises smaller panels, and more of them.
For someone who wants to extend an existing setup, those 330W panels may be just the ticket.
No warranty though, as TTT said.
Exactly my conundrum with the Solis I bought … cannot go above 360w really, due to the amps limit.
But with 3kw more on the Solis, I can heat the geysers faster, batts charge faster …
So either I get 2nd hand panels, or I reshuffle everything and put the 350’s of the main system onto the Solis, and upgrade the main systems panels. And then I have spare panels lying in the garage with the tools I bought. 
All that with me, myself and I fighting like there is no tomorrow, twice on Sunday, over the ROI, or lack thereof, cause my system is balanced until the clouds move in …
So maybe sit on my hands and wait for that one-time buy and then punch on that onetime.
Cause if I make any move here … it is going to cost an installer to come in to reshuffle #($*% everything … AGAIN!
The 500W panels I’ve got will work with the Solis. Let me explain my thinking.
The Solis has an Isc of 17A, but will limit to 11A, so you want your panels to be around there as well.
The 500W panels (HiKu5 I believe) have an Imp just over 11 amps. That’s STC. In reality it’s not even going to get there. I just needed the Isc to be below 17A. This is also at a Vmp of 45V.
The 650W modules (HiKu7) are over 18A Isc, with operating current around 17A, and a lower Vmp of 38V.
The 500W panels (and maybe one more of them) is much more suitable for the hardware in this case. Higher voltage and lower current.
The 650W panels will run at 11A, 38V, or 420W each. A spectacular 35% waste.
1 Like
I see where you are going with this. Interesting.
Let me know when you make the final decision?
I have a couple of setups with 540-555W (~13.8A Isc) panels on 11A MPPTs. They clip at around 440W from 10h00 to 14h00, the total kWh lost is minimal.
1 Like
They are already on the roof. I had some family visit recently which meant I had help, so I installed the panels so long. Still have to do the wiring.
Of course, I cannot find 500w Canadians.
But found these 550w - NMOT fits quite nicely it seems?
6 of them?
Probably fine.
Or ask your namesake if his supplier still has the 500W modules.
So reading all this…solar stays a work in progress then?
No damage done then?
So the MPPT will limit the current from the panels at max capacity?
The panels are within the Isc spec for the MPPT, so it can handle it. If you exceed that limit then you might run into problems. Most high-voltage MPPTs will have an Isc rating in the specs.
1 Like
To add to @_a_a_a , the risk of damage is only there if you exceed the Isc rating of the MPPT, the maximum input current. If your Imax (the current when the panel is doing max power) is more than the maximum continuous power the MPPT can handle, but the Isc is less than the rating of the MPPT, then it will safely clip the rest.
The reason the Isc is important, is that when the MPPT is sweeping for the maximum power, it will gradually lower the impedance, increasing the current, until it finds that optimum. During this sweep, the current could theoretically ramp up as high as the Isc of the panel (obviously it cannot go higher than that). While the software will typically avoid sweeping past such a point, this still leaves you with a system that has lost the quality of being safe by design. Now it is only safe as long as the software reacts fast enough… 
1 Like
Has anyone seen a MPPT that has died as a result of excessive V/I?
“Vmp”
YES… my own mistake.
1 Like
So Vmp is the most significant parameter.
My electronics experience agrees: Voltage is the parameter that electronics is most vulnerable to. Excessive current normally doesn’t normally produce an instantaneous failure like over voltage.