I am being told I can charge my Lifepo4 batteries using an Orion-Tr Smart 12v to 12v DC to DC Charger 30 Amp directly off of my trucks 7 pin wire. My truck is a 3500HD duramax, and I believe the charge wire is 10ga. The fuse is a 30A fuse under the hood. I want to be sure I am not going to burn up an expensive alternator or wiring. Does this sound correct? Thanks!
I wouldn't. From what I understand, those chargers pull more like 35A at max. Even if it was only pulling 30a, you should not be running right at the limit of the fuse and wire. 10ga isn't going to work well either unless it's a really short run.
The dealer was saying I could go in and set it for max draw and the charging profile, and that is why I should get the smart 30A instead of just the cheaper 20A. I really didn't want to run expensive wires from the truck battery back, but wanted some amount of charging while driving until getting solar installed.
You can’t set a maximum current in the Orion TR Smart, but you can kinda get around it by setting a minimum input voltage at which it will run. When the input voltage gets pulled down to that level it will start to throttle back its output. So this will all depend on how how much voltage drop you get over your wiring under load. You’d need to experimental work out what voltage gives you the desired current. I do this on my catamaran (with a 12/24-15) so that it’ll pull the full 30A with both motors running and about 20A with only one. It’s not perfect. It’ll still pull 30A for a while until the voltage sags.
I wouldn’t do it this way on your truck.
