Dc charge from truck

carl.swoyer

Well-known member
Ok ,
Charge while driving!
After many years of dc, charge conversations, I found a no-brainer. At least for me.
I put my norcold on setting 1 while driving. Everything inside was still cold after 6 hours of driving, and my batteries were taking on a charge. And I'm doing the same at night while dry camping
Only an FYI.
Works for me.

Sent from my SM-A526U using Tapatalk
 

wdk450

Well-known member
Since I get no indication of a malfunction with the trailer charging circuit from the truck until there was a non-charging problem (fused circuit with the fuse under the hood), I finally used my electrical savvy to install a self-resetting circuit breaker (rated slightly lower than the truck fuse - I think the truck has a 25 amp fuse and I installed a 20 amp self-resetting breaker) at the trailer umbilical cord connection box in line with the truck charging wire before it connects to the trailer wiring. This opens the charge line for "glitches", restores charging current after the "glitch", but doesn't blow the truck fuse.
This has worked well with no problems for over 4 years.
 

centerline

Well-known member
Ok ,
Charge while driving!
After many years of dc, charge conversations, I found a no-brainer. At least for me.
I put my norcold on setting 1 while driving. Everything inside was still cold after 6 hours of driving, and my batteries were taking on a charge. And I'm doing the same at night while dry camping
Only an FYI.
Works for me.

Sent from my SM-A526U using Tapatalk
what does switching to setting 1 on the fridge do for you?..... are you running a residential fridge?...

RV refrigerators operate on propane, but the control board uses a wee bit of energy to sense and operate the fuel valve and ignitior.... and changing the setting does hardly nothing to conserve 12v power.... but it will conserve propane.

..and the charge you get from the truck to the rv batteries may offer a few amps due to the resistance in the wire, but it could be enough to keep the battery from being discharged more than it otherwise would, while you drive...

the resistance causes the voltage to drop, and if the voltage drops, there is no pressure to push the amps....and the farther it gets down the wire, away from the charge source, the lower the voltage will become, and in this scenario the current flow can actually stop flowing.

if one were to install a #4ga or larger wire, it would help a lot with the current carrying capacity of the charge wire.... because if the truck batteries are fully charged, the voltage in the system will be at its "float charge" level, which isnt hardly enough voltage to push the amps thru a smallish wire of the length needed to get it to the RV batt, and so it just trickles its way rearward.... and the bigger the wire would allow more current/amps into the wire, and make the leisurely stroll back to the house batteries faster....
 

ILH

Well-known member
If memory serves me correctly, the hot wire in the typical trailer connection from the vehicle provides only about 7amps. That's just barely enough to help charge the onboard batteries while driving and run the trailer lights. As Lou stated, a typical RV style refrigerator is propane fed and uses minimal 12v to run the circuit board.

If your trailer has a residential (120v) refrigerator, that's an entirely different ballgame... I just had my truck equiped with a DC to DC charger to provide up to 50 amps through a secondary cable. Now my refrigerator runs while I drive - regardless of distance.
 

wdk450

Well-known member
The MAIN reason the charge wire is on the standard 7 pin truck connector is to keep the main trailer battery charged FOR THE 12 VOLT TRAILER DISCONNECT ELECTRICAL EMEMRGENCY BRAKE SYSTEM. THIS IS VITAL TO TRAILERING SAFETY!!! More 12 volt trailer battery charging beyond this is just a small slight bonus to the needed braking safety charging.
 

oldelmer1

Well-known member
ILH, would you mind explaining what the DC to DC charger is and the secondary cable is all about.

Thanks.
 

ILH

Well-known member
The MAIN reason the charge wire is on the standard 7 pin truck connector is to keep the main trailer battery charged FOR THE 12 VOLT TRAILER DISCONNECT ELECTRICAL EMEMRGENCY BRAKE SYSTEM. THIS IS VITAL TO TRAILERING SAFETY!!! More 12 volt trailer battery charging beyond this is just a small slight bonus to the needed braking safety charging.
You are absolutely correct. My mind slipped on this one. Thanks.
 

ILH

Well-known member
ILH, would you mind explaining what the DC to DC charger is and the secondary cable is all about.

Thanks.
Sorry I haven't replied sooner - I forgot that you had asked about this.

Here's a posting from when it was installed in my truck and trailer. If you have questions, let me know

Original posting
 
Top