Wiring from truck to camper

[Chris R]

Can I connect the battery in the camper to the truck battery on a line that is fused at 20a? The reason I ask is I have a Painless Wiring circuit block (This one) that I intend on using (leftover from another project) and the wires are only rated for 20 amps.

Thanks!

Chris

 

[pods8]

I'm a little confused on what you're trying to do here with that circuit block. Most folks have a solo dedicated line (fused of course) running back to the camper from the battery with whatever isolation method they prefer.

What concerns me about what you are saying is "the wires are only rated for 20 amps". To charge a battery you don't want to be anywhere near the rated capacity for a wire because by that point you've had a bunch of voltage drop. You need to minimize voltage drop back to the battery because you need a higher voltage than what the battery is to make it take a charge (ie in terms of a water hose analogy there needs to be "pressure").

 

[Chris R]

I was hoping to use a switched circuit on that circuit block to keep the camper from draining the battery when the truck isn't running. What gauge of wire would you recommend running from the battery to the camper, and what amperage would you fuse it at?

 

[UglyScout]

Using my handy dandy wire gauge chart I'd run 8 gauge wire on a 30 amp self resetting breaker to a battery separator - then to your battery then to your fuse block...


See this thread for info on separators:
My link

 

[pods8]

I was hoping to use a switched circuit on that circuit block to keep the camper from draining the battery when the truck isn't running. What gauge of wire would you recommend running from the battery to the camper, and what amperage would you fuse it at?


There are other ways to isolate, if you like switch based use a solenoid, relay, etc.

10ga minimum, bigger is better.

I've got mine connected through a DC-DC charger that only pulls 7.5amps so I've just got a 15amp self resetting breaker on mine but I know many other folks use 30amps.

 

[Chris R]

I have some relays that I think I will use instead, and since I need to get wire I will run 8ga from the truck battery positive.

What gauge wire would you run from the negative camper battery terminal to the negative terminal on the truck? Also 8 gauge?

 

[pods8]

I have some relays that I think I will use instead, and since I need to get wire I will run 8ga from the truck battery positive.

What gauge wire would you run from the negative camper battery terminal to the negative terminal on the truck? Also 8 gauge?


Same as the positive.

 

[K7MDL]

The negative wire size is the same as the positive wire size since you have no other reliable DC return connection back to the battery. Consider the batery to battery a closed circuit. Then look at each piece and find the weakest link in the system and ask if it is up to the task. If it goes in, it must come out.

I prefer to fuses or use a breaker at both batteries. Isolators in the middle usually located more than a foot or more away. Remember the fuse/breaker located inches from each battery is there to protect your wire from melting and starting a fire, not to protect the battery. Also watch for pinch and abrasion points on your wire runs, use sheating. Support them well, vibration is not friendly. Use fine strand quality wire, not the stiff stuff (like 7 copper strands). Marine wire is tinned, hi temp, and fine stranded, about the best.

 

[natjwest]

Not that I recommend it, but I know some people run the black wire to ground in the truck bed or frame somewhere rather than all the way back to the battery. Sometimes, I kinda wish I had done that. You can save yourself some cash by buying half as much wire, which allows you to upgrade your positive line (get a fatter gauge). But you have to convince yourself that your ground in the truck bed is good, which I couldn't do.

Well, technically, for me, the negative wire from the camper to my truck doesn't ACTUALLY connect to the battery. It connects to a ground in the engine compartment which I know is a good ground, which eventually gets back to the battery.

FYI, I run 6 gauge between truck and camper with a 50 amp breaker.

 

[pods8]

Not that I recommend it, but I know some people run the black wire to ground in the truck bed or frame somewhere rather than all the way back to the battery. Sometimes, I kinda wish I had done that. You can save yourself some cash by buying half as much wire, which allows you to upgrade your positive line (get a fatter gauge). But you have to convince yourself that your ground in the truck bed is good, which I couldn't do.

Well, technically, for me, the negative wire from the camper to my truck doesn't ACTUALLY connect to the battery. It connects to a ground in the engine compartment which I know is a good ground, which eventually gets back to the battery.

FYI, I run 6 gauge between truck and camper with a 50 amp breaker.


Wire isn't really that expensive, buck up and do a proper system. 6ga $26/25ft spool, 8ga tinned $19/25ft spool, 10ga tinned $12/25ft spool. My $.02

 

[K7MDL]

The truck beds may be composite (newer Toyotas), rubber mounted, or bolts between painted chassis frames and truck bed and not a guaranteed good electrical connection.

My 2005 Dodge RAM trucks have a braided bonding strap between the front of the bed and rear of the cab. It looks like it might be equivalent to #8 wire, but is also open to air and corrosion over time. You still have to guarantee your camper connection the truck bed is metal, not paint. Then you get to deal with corrosion prevention on that likely scraped area. Running a pair of #8 or #6 wire removes all doubt, no paint and corrosion issues, and disconnects easily and cleanly when the camper is removed. Takes about the same effort to install 2 wires at the same time as just the one wire. Connecting the negative cable to the engine compartment common battery ground bolt is a good place to do that.