A charge controller simply handles the voltage from the solar panel for you. You wire your solar panels to it, and wire it to the battery.
Yes but...
I know a lot about solar, I put in my system in two hours on Monday. But I didn't know I could adjust my controller to maximize its output. Not all controllers are adjustable but mine is (got it used no manual yet). There was a post up yesterday here and I read the link all the way through. He had the same controller (Morningstar MPPT 40) and he explained how to adjust it to suit the batteries needs. I am humbled, I have installed 4 larger systems on cabins (years ago but still), I have solar on my sailboat (along with wind), I had not heard I could adjust a controller to the battery makers specs!
I also learned from him that I could tie my house/starting/controller/alternator all to one junction, switched and fused, my solar will act as an alternator if alternator goes out. I didn't think you could do that safely. With the engine running, shouldn't the controller cut its output because it 'see's' 13.8? Or will the alternator cut its output because of the solar output?
ITS A WAR OF THE WATTS! (amps doesn't have the same ring)
I know, we want to keep the starting batteries away from the house batteries but still, it will work. Monday, I disconnected my alternator and ran my van till this evening, just off the batteries (only the two starting batteries, don't know the amp hours but they are 950/1000CCA's)) and solar. The charge controller is wired into the van's charging system in place of the alternator's output.
Its a diesel so I don't need any 12 volt to keep it running, just starting it and shutting it off. Turns out I could lose my alternator and run this way for quite some time, even using my headlights. If I tied in the house batteries, probably forever.
Yeah, its simple and then it can get complicated. Just tonight, I read about the frankenfridge...so guess what I am doing tomorrow?
I have a shit ton of power, almost 400 amp hours in batteries, two Kyocera 140 panels with #4 cables so I can move them off the roof into the Sun when I park in the shade, 2500 watt true sine wave inverter, another 1000 watt inverter as a back up. I got all this for almost free (100.00, no shit). All I was powering is a few led lights, a 100 watt PA head, two cheesy 12 volt fans, that's it. Talk about headroom. I was thinking about selling off a panel and two of the batteries and the smaller inverter to another vandweller for 100.00, make my system free.
My first system was dirt simple, not even a real controller but a alternator gauge out of a VW to know when to disconnect the panels. Never smoked a battery though and it worked for years.
I can see how it gets confusing. Solar is all 12 volt, then you invert to 120 AC, now you can have two different wiring set ups. We did dual on one of the cabins, ran 12 volt right next to 120, got us out of inverter losses but what a rats nest. There was no led yet, just lots of 12 volt light bulbs, RV style. Even the cabin's stereo/mp3/aux/cd was a Kenwood out of a car mounted in a drawer. The video posted above, the southern gent and his system, that broke it down pretty well I think, most should be able to follow along. Not sure why he only used red wire though...
The other complication for many is figuring out your power needs. I have headroom so I got out of all that math. I can almost run a full size fridge for 6 hours a day given enough Sun. I think. But I don't want to think.
The frankenfridge thing, I don't have to really know what each part does, just have to buy them and assemble them in the order he describes. Boom, cold Pepsi. Gotta get all that written down and then thank the poster.
Even those that know quite a bit about things can learn more about those things.
And we count on you and others to explain it like we're high five.