Building a Heavy Duty Charging Circuit for Camper--how big?
So I discovered my camper isn't charging when I'm driving and diagnosed why: my charge wire fuse was burned from God knows when, and my solar panel connector was corroded to the point of not working at all. I'm ordering parts now.
In the meantime, I want to make a new charging circuit for my camper. Why? Two reasons. The stock ampacity is******(20 amp fuse, likely far less than that in the real world) and the worst part is that it's hot all the time, so my camper would draw from my truck batteries and kill them. So as to avoid that issue, I'd like to upgrade.
Looking online, many have built 100+ amp charging circuits with 2 AWG wire. This strikes me as overkill but I'm open minded enough to reconsider that thought if someone can convince me. I do understand that voltage drop is an issue with only 12-14 volts and so I can be persuaded, however, it is difficult to splice wires as they increase in size so I don't want to go nuts.
I plan to alleviate the "hot all the time" problem by using a continuous duty solenoid and by using a relay to close that solenoid so as to protect whatever circuit I steal the key-on 12 volts from. The solenoid will be rated for much more than I plan to run wire for, so the real question is determining what sort of ampacity this circuit ought to have. I will fuse the wire at the appropriate ampacity which will protect the solenoid and the wire running down the frame to the camper.
So how big of a wire do I run? The camper's charge wire is 10 AWG, I believe. I am not going to install a separate plug for the camper so the 7 wire plug in the bed is what will be being used to charge the battery.
I'm inclined to use a 40 amp fuse and run 8 awg wire. This seems small but is probably enough for what I'm expecting to do. My refrigerator will NOT run on propane when driving; it blows out. So I need to have enough current capability to get some positive charge into the battery and run the fridge.
Is a 40 amp circuit enough? The factory circuit in my truck is only 20 amps and so this seems like a significant upgrade, but by the time I run the wire all the way down the frame, jumping from 8 to 4 or even 2 awg isn't a huge expense and I could go bigger.
If I go larger than 8 awg, though, I face another issue. My truck has two 7 pin connectors--the factory one at the bumper and a secondary one I added in the bed. I plan to cut the charge wire that goes to the secondary one in the bed and hook up the new charging circuit only to that wire, so that I don't cut any factory wires and so that my charging circuit is only used for the truck camper. If I use a wire larger than 8 awg, I think I will have a hard time splicing that into the 8-10 awg wire that is existing. What kind of junction block is available to make this transition cleanly? I'm not against running a larger wire to reduce voltage drop, but if I can't make a clean connection at the rear where I hook it up, all may be lost that is gained by the larger conductors.
I know I've written a lot so here's the Reader's Digest:
1. I want to run an ignition only charge circuit for camper
2. I want to use big wire and fuse it appropriately but I don't want to go complete overkill.
3. I want to know how to hook up whatever big wire I end up using at the camper end because splicing a 2 awg wire to an 8 awg one is not easy.
Thanks all!
In the meantime, I want to make a new charging circuit for my camper. Why? Two reasons. The stock ampacity is******(20 amp fuse, likely far less than that in the real world) and the worst part is that it's hot all the time, so my camper would draw from my truck batteries and kill them. So as to avoid that issue, I'd like to upgrade.
Looking online, many have built 100+ amp charging circuits with 2 AWG wire. This strikes me as overkill but I'm open minded enough to reconsider that thought if someone can convince me. I do understand that voltage drop is an issue with only 12-14 volts and so I can be persuaded, however, it is difficult to splice wires as they increase in size so I don't want to go nuts.
I plan to alleviate the "hot all the time" problem by using a continuous duty solenoid and by using a relay to close that solenoid so as to protect whatever circuit I steal the key-on 12 volts from. The solenoid will be rated for much more than I plan to run wire for, so the real question is determining what sort of ampacity this circuit ought to have. I will fuse the wire at the appropriate ampacity which will protect the solenoid and the wire running down the frame to the camper.
So how big of a wire do I run? The camper's charge wire is 10 AWG, I believe. I am not going to install a separate plug for the camper so the 7 wire plug in the bed is what will be being used to charge the battery.
I'm inclined to use a 40 amp fuse and run 8 awg wire. This seems small but is probably enough for what I'm expecting to do. My refrigerator will NOT run on propane when driving; it blows out. So I need to have enough current capability to get some positive charge into the battery and run the fridge.
Is a 40 amp circuit enough? The factory circuit in my truck is only 20 amps and so this seems like a significant upgrade, but by the time I run the wire all the way down the frame, jumping from 8 to 4 or even 2 awg isn't a huge expense and I could go bigger.
If I go larger than 8 awg, though, I face another issue. My truck has two 7 pin connectors--the factory one at the bumper and a secondary one I added in the bed. I plan to cut the charge wire that goes to the secondary one in the bed and hook up the new charging circuit only to that wire, so that I don't cut any factory wires and so that my charging circuit is only used for the truck camper. If I use a wire larger than 8 awg, I think I will have a hard time splicing that into the 8-10 awg wire that is existing. What kind of junction block is available to make this transition cleanly? I'm not against running a larger wire to reduce voltage drop, but if I can't make a clean connection at the rear where I hook it up, all may be lost that is gained by the larger conductors.
I know I've written a lot so here's the Reader's Digest:
1. I want to run an ignition only charge circuit for camper
2. I want to use big wire and fuse it appropriately but I don't want to go complete overkill.
3. I want to know how to hook up whatever big wire I end up using at the camper end because splicing a 2 awg wire to an 8 awg one is not easy.
Thanks all!
