Can I connect a 12 awg solar panel cable that came mounted to a 8 awg solar cable that I have connected to a Morningstar TriStar 45 amp PMW controller? I get over 13 volts at panel but only 12.68 at controller.
Depends on the distance, but if it were me, I would change it out to 8 awg, better yet make the whole line 10/2, but at least 8 to help minimize that voltage drop.
That's not too bad if you go all 8awg. I just plugged it in and and came back around .26% drop at 25'. How long is the 12g you are wanting to tie into? Of course, having a non continuous line, you'll loose a little at the connection point as well... assuming you were just going to do a quick connect or something similar.
The 12 awg is 35.4 inches with mc4 connections. I went with the 25' cable since I wanted to be able to move the panel around, we dry camp in some shady areas in the mountains, so the camper would be in the shade most of the type.
Just out of curiosity.. whatcha throwing up there? You'll be happy with your Tristar! Should handle up to 600watts really nicely. I use the Tristar 45 mppt. Nice units...
The 12 awg is 35.4 inches with mc4 connections. I went with the 25' cable since I wanted to be able to move the panel around, we dry camp in some shady areas in the mountains, so the camper would be in the shade most of the type.
Gotcha. If you really don't want to rewire the panel then I would at least trim the leads back as short as possible. Leave enough so you can rewire more than once if need be in the future. It won't make a fantastic difference, but every little helps.