After living in the camper for several months, it was time to evaluate my options for charging the camper batteries. The generator that came with the camper was completely impractical. While it was a selling point for me when I bought the camper, I soon realized the thing was a propane-guzzling noise machine. It was also kind of a lemon. I had issues getting it to run consistently and when it did, it totally killed any kind of relaxing vibe I had going on. It also eliminated the option of stealth camping completely. It was big. It was heavy. It needed to be run regularly. It had to go. I sold the generator and was thrilled to see the giant compartment of space that opened up for me. However, since I don’t yet have solar and don’t have a house to regularly charge my batteries, I knew I needed a solution for keeping the batteries at their optimal charge state.
This mod was suggested to me by fellow Bigfoot folk (thanks Laura & Blake). While it did involve some semi-advanced wiring skills, I am totally sure that if I can do it, anyone can. The basic idea is this: Wire your truck’s battery to your camper battery so that when you are driving, you are charging your camper batteries. I will go over all the parts in between like a circuit breaker and a mACR to keep the camper from draining your truck battery (because no one wants a dead truck) and the winch plug to make it all disconnect easily (because the whole point of a truck camper is flexibility of being able to detach it). Below is the wiring diagram so you can see the basic overview of everything involved. I’ll explain in detail below.
Starting from the truck, the negative cable is basically a straight shot from the truck battery to the winch plug to the camper battery. The positive cable is where all the action happens. From the truck battery to a circuit breaker to a mACR to the winch plug to the camper battery. The circuit breaker should be wired as close to the source (the truck battery) as possible. This will prevent it from draining your truck battery when it’s not connected. I also added a mACR for extra protection (because I am the ultimate ditz and I know it would have only been a matter of time because I parked my rig and forgot to switch off the circuit breaker). I didn’t even want to risk it. The mACR automatically senses when the truck battery is putting out enough voltage to push it to the camper. When it’s not, it automatically shuts down the circuit. I don’t even have to think about it and don’t have to worry about waking up stranded. Worth the $50 if you ask me. However, if you’d rather skip the mACR, go for it. This mod can certainly be done with simply a circuit breaker. Just don’t forget to flip the switch as soon as you park.
Since the camper comes off the truck, I needed to be able to disconnect and connect these wires easily whenever necessary. The solution for this is a winch plug. It’s as simple as pulling apart the plug when ready to unload the camper.
The setup is pretty basic but the job itself is somewhat intense, as you have to measure and create all the cables yourself (crimp ring terminals at each connection, protect with heat shrink tubing) and then run it down through the truck, wrapping it in split loom and ziptieing it all to keep it in place. I also mounted the circuit breaker and the mACR to the truck with heavy duty mounting tape so that I didn’t have to drill into my truck’s frame. Below is a list of all items needed along with links to the product pages.
- 4 AWG Copper Wire – 60 ft – Black & Red $55
- 14 AWG Copper Wire – 10ft – Black $8
- 5/8″ Split Loom – 50 ft $15
- Wire Shears $25
- Heavy Duty Wire Crimper $38
- 4 gauge Ring Terminals x8 $10
- 14 gauge Ring Terminal $7
- 14 gauge Quick Disconnect Spade – Female $7
- Adhesive Lined Heat Shrink Tubing – 1/2″ $10
- 120 Amp Circuit Breaker $27
- Mini Automatic Charging Relay $45
- Quick Disconnect Winch Plug $17
- Heavy Duty Mounting Tape $7
TOTAL COST: $271
This is not an inexpensive mod but to me, it is well worth it. You could also save a lot if you have an electrician friend with a well stocked garage. Specifically, someone with a big enough crimper and shears and some spare terminals, heat shrink and split loom. I didn’t have anyone so I had to buy everything myself.
I want to note that this mod is by no way a means to regularly charge your camper, unless you’re road tripping and running the truck long distances every day. This is really only meant to be used when the truck is putting up significant mileage. If you’re stationary, this isn’t going to do much. But if you’re bouncing around from various boondocking sites, this is a great way to make sure your batteries are charged up when you’re done driving for the day.
I’ll also say that I was told (like all of us) that the pigtail from the truck to the camper will “trickle charge” the batteries as the truck runs. This is simply not the case. The pigtail does absolutely nothing for my batteries. It simply controls tail lights.
As you can see, the diagram + the list of parts should be pretty self-explanatory but feel free to email me with any questions you may have at firstname.lastname@example.org or comment below.