Re: Excellent price on 300w solar panels las vegas craigslist
Reply #16 –
In reply #11 Bob asked if he could add the Renesola JC300M panels to the panels he already has.
I agree with rsihnhold's replay in #13 that they would not work with the controller in Bob's picture, however, I believe the panels that Bob has are probably VOC 21v (Volts Open Circuit), not 18 volts. The 18 volt panels were sold as NOT needing a controller because they could be connected directly to the batteries.
Renesola JC300M panels are Volts Maximum Powerpoint (Vmp) 36.6 volts and VOC 44.8 volts while Bob's panels are probably VMP 17.5 volts and VOC 21 volts. So Bob could buy a higher voltage controller and pair his current panels to obtain VOC 42 volts and combine them with the Renesola JC300M panels. This would not be ideal because of the slightly mismatched Vmp and I would not do it.
The other item mentioned here is that there are controllers available which can control up to 150 VOC from panels which allows smaller wiring from the roof. I would caution you about two items: 1. If you ever touch the bare wires carrying 150 volts DC from the roof, you are in for the shock of your life, and 2. A solar contoller operating with supply voltage of 150 volts is much less efficient than that same controller operating at 75 volts (at 150 volts, the controller will get quite hot). My panels are VOC 37.4v and VMP 29.9v. I have them in pairs so controller sees VOC 75volts and VMP 60volts.