I purchased 10 - 250 watt sharp solar panels probably 4-5 years ago. They are 60 cell panels and I have them wired 2 in series. Anyways on hot days its not ideal as the voltage isn't high enough. I use a midnite charge controller and often see "input lower than output" in summer. I almost forgot, I am charging a 48 volt bank.
I'm currently moving them off of a temporary wooden rack (temporary like 1 1/2 years now) to the roof and I will be wiring 3 in series which leaves with an extra panel I can't use. Wired this way I could technically wire 18 panels up.........if I had them. Not having any luck finding 250 watt panels, their all smaller or a lot bigger. I've found some Canadian Solar 270 watt panels priced decently within driving distance and it looks like their pretty similar voltages, amps, etc. Their also 60 cell and poly like mine. Now I know my 250 watt panels will hold these back from producing their full power but was wondering what the experts thought about this arrangement?
Here's my Sharp Panels:
voc - 37.35
isc - 9.03
vmp - 29.98
imp - 8.34
Here's the Canadian Solar Panels:
voc - 37.9
isc - 9.32
vmp - 30.8
imp - 9.75
Now that I write this I'm confused as the numbers seem backwards from one panel brand to the other. Here's a pic of the label from one panel to another. I also know that as my existing panels have aged their probably not putting out what the tag says so I don't know if any of you have added to an existing charger or if you added another charger instead. I don't really want to add a second charge controller as their pretty pricey.
