Hey everyone! I've just finished revamping my overland trailer after three years, and I'm about to set up the solar system that came with it. The previous owner used three 100W Mohoo panels in parallel, but I'm thinking about upgrading to one 300W panel instead. I have a Renogy Rover 20A MPPT charge controller that has a max input of 100VDC and 260W at 12V. My question is, will this 300W panel exceed what the charge controller can handle? The panel is listed at a max voltage of 25.2V with an optimal current of 11.9A, and realistically, I expect to get about 225W on a good day. Also, I've heard that the controller will only pull as much power as it can handle, is that true? Lastly, the previous owner didn't use any fuses in the solar setup, but I'm planning to install a 30A fuse between the charge controller and the battery, and a 20A fuse between the panel and the controller. Does this sound right to you?
4 Answers
Generally, using a 300W panel should be fine with your MPPT controller since it will only draw the amps it can utilize. Just ensure you don't exceed the amperage limits of the terminals and wiring connections. For your 20A fuse on the MC4 connector, keep in mind that it's mainly for peace of mind since a shorted panel won't significantly raise the amperage. It’s recommended to use fuses primarily if you have multiple panels to prevent backflow issues.
The answer largely depends on the quality of your charge controller. Some cheaper MPPT models might fail if they detect they can pull more power than intended. Just remember that the fuses are mostly for protecting your wiring, as the controller components can fail much quicker than the fuses will blow.
You definitely want to avoid pushing voltage limits. As long as you stay below the max voltage and your fuses are in place for wiring protection, you should be fine. Just be cautious with the amperage; that's where issues can arise. Also, be mindful of your MPPT controller's capacity—overextending it could lead to issues down the line.
Yeah, I've heard that some controllers can get fried if they try to pull too much. Just keep an eye on that amperage and you should be good!
Thanks for the insight! Just to clarify, should I also consider a breaker on the load wires, or is that unnecessary since I'm not using load outputs?