Have a similar concern hoping someone can add info.
I have a charge controller connected to my battery and panels on that. All is great shuts power off from the panels when charged and connects power from the panels when needed. To this i want to add an Alt. feed to supplement the solar when it either isn't putting out or cant put out. Im not worried about the battery or anything "behind" the controller but in regard to the panels themselves.
Will it be safe for the solar panels so see this feed from the Alt. or will a power supply on the panels some how "blow" them out (basically running the Alt and Solar in parallel into the controller)? Im assuming that it should be fine since if panels are wired together and some get sun but other dont, some would "see" voltage from the others and they are fine, but anyone know for sure?
Diagram of how I want to hook this up is attached.
TIA for any help
Dont do it !
Alternator can output far more current than most charge controllers are capable of carrying.
If your solar is same voltage and its battery is of similar chemistry as the car, just connect alternator to solar battery thru a isolating relay of your favourite type.
So I wanted to follow up on this. I did this but with a DPDT switch between the truck and the solar panels so I could manually switch between the 2 sources going into the charge controller. And it works. Not sure why everyone (I posed this question in other places too) kept saying not to try this without really any supported reasoning why but I did it anyway (the main risk was a $30 charge controller and that was acceptable to me).
My OEM trailer wiring will apparently support up to 30A at least that's what the factory fuse is rated to. I have a 20A solar controller...important thing to note here is that, at least in my case, the Amp rating on the charge controller is BOTH the max charge current and max output current capability so make sure you have headroom. I bought mine based on the max output and was unaware of what the max charging could be. So I was very surprised to see that my "house" battery when charging off the truck will charge at a rate up to 20A (though it typically only maintains about 17A continuous). This frightened me at first because most battery chargers have like a 6A and 2A charge setting and this seems really high in comparison but given that batteries can purportedly handle charge current at about 20%-25% of their rated AH rating and this is a 95AH battery I should be good. Additionally this rate is not always constant, the charge controller does do it's thing and as the battery charges has been dropping Amps and is now typically charging at roughly 10A after a few 1hr commutes home from work.
An interesting note in my case is that the charge controller also seems to have some logic built in (based on resistance maybe???) and it seems will only pull a "safe" amount of amperage to charge based on the wire gauge used??? As an example when I hooked everything up to test I had really small gauge wire, like 20awg as I just wanted to see what would happen. I noticed that the controller was charging the battery at a max of about 8A. Max I saw on solar charging was like 5A so that seemed about right. So I ran the connections with 16awg wire so it would be plenty capable. But with the 16awg wire the controller will typically charge at a constant 17A when the battery is low, tapering off as the battery charges. None of this is mentioned in the "extra" good chineese instructions, lol
Anyone know more about how that's accomplished?