Wire Size to Brake Magnets - Is it Worth It?

[moe_f]

Now that my 2012 5th wheel is beyond the warranty period I have been researching increasing the wire gauge to the brake magnets.

I've seen numerous testimonials about the improved performance after wire size upgrade, soldering the connections, using the 'star' circuit, etc. , but have not seen anyone express disappointment relating to the performance after these upgrades. Does this mean there is only upside to doing this or have some of you found the results of doing this upgrade to be lacking? If you were disappointed I would like to hear why so that I can make a better informed decision before going ahead.

Thanks

[fj12ryder]

Ah, I see.

The cap on mine fits really tight so that you have to push the plug in pretty hard to get the cap to snap down over the end. A very snug fit. I can see why you'd want to replace them if they don't fit snugly.

[BruceMc]

There's a tang on the inside of the cover, just like the 7 pin setup. Push in until the cover snaps over the plug shoulder, nice and secure.

On the plastic RV connectors, it seems like the tang is set too far back. There was always a 1/4" play, which of course, was the difference between connected and partially/not connected.
I've had a number of them as well, and adapters to 6 & 4 pin. All junk.

Since we sold the fiver back in early 2010, I don't have anything that takes the 7 pin RV so I've swapped all of them for the 6 pin connectors. We have a number of other utility trailers that use the 6 pin round & 4 pin flat.

[fj12ryder]

Ah, I see about the onboard battery. Now that I think about it I knew that, it just didn't register. I've had trailers with brakes and no onboard battery. Duh.

The one I have looks like the trucker's style, but plastic instead of metal and does have the flat pins. But I think I'll stick to the old "If it ain't broke, don't fix it". The lid locks the plug in place.

What holds the upper one in place?

[BruceMc]

I've had nothing but trouble from those cheap 7 pin RV connectors. When I had those, I had to use a bungee cord to keep the plug pushed into the socket so it would maintain some semblance of contact.

Like MW, I use the metal trucker's style split pin plugs/sockets on everything these days. I even changed the standard GM plastic socket out for a 6 pin metal socket on our GMC Canyon because the 7 pin plastic angle-contact style was nothing but a headache.

Here's what we use:


and here's the 7 pin trucker's style:

[mrekim]

fj12ryder wrote:
The onboard battery supplies the power for the trailer braking. Or am I mistaken here?

No the TV supplies power for brakes. Battery only supplies power for breakaway switch.

[fj12ryder]

Strange, I've never heard that many people having trouble with their RV plugs. A few, but most seem to be because the unit was incorrectly wired.

I don't really see how the plug will impact the braking, since all that is relayed through the wire/plug is the signal for the brakes to activate. The onboard battery supplies the power for the trailer braking. Or am I mistaken here?

How are the plugs you've installed different from the originals? Just curious.

[MEXICOWANDERER]

This is like worrying about stains on the sofa when the house is on fire.

Absolutely guaranteeing voltage will * be * there * when you need it is light-years more important. Soldering magnet leads is a start. I used a JUNCTION BOX for a truck trailer rig (7-way) that is weatherproof, to CLAMP all harness wires to a one-spot-does-all location. The #10 studs in the junction box are plenty to contain 6 brake's worth of power.

RV Trailer plugs and sockets are garbage. Show a slotted RV plug and socket to a big rig owner and he'll fall over laughing. I have ripped so many six-way plugs and sockets out and replaced them with "real stuff" I lost track decades ago.

A big-rig SPLIT PIN (rather than a solid pin) plug and socket is the way to go for reliability. We're talking light-years and magnitudes more reliability. And they are easy to change.

Marine DUPLEX wiring is perfect for running beneath a trailer. But I added a twist - an ADEL CLAMP bolted to the backing plate for strain relief. A steel ADEL CLAMP, and 14 gauge duplex cable can take a 100-pound yank and laugh it off.

[Fleetwood99]

Don't forget the one wire that might be the most important. Grounding Wire the heavier gauge the better 10AWG minimum going thru Plug. If, your running lights on Trailer dim down when applying brakes or your Turn Signals dim. Bad ground wire 99% of the time.

Happy Trails

[fj12ryder]

I have no idea what the wire is on the truck. I bought it with the wiring already in place. I guess that is one of the first places to start checking. This is on a 1-ton dually so the plug may even be factory. I wonder if there is any way to tell?

Thanks for the information.

[BruceMc]

At 3 amps max on each brake, you'll have a total of 12 amps at full braking. 14 gauge handles 15 amps, 12 gauge is 20 amps. If the factory wiring on your trailer from your TowVehicle connection point is at least 14, you'll be ok. This circuit doesn't see full load very much, and for very long. Chances are the normal current across this circuit ranges from 0 to 1 or 2 amps per brake - 0 to 8 amps on the main line.

It is preferable to have a heavier mainline to lessen current drop over the length, however. What size wire is on your TV? I ran 10 gauge on our '93 GMC. I think the factory brake wire on our new '12 GMC Canyon is 12.

[fj12ryder]

Hmm, mine sure didn't look like 10 gauge wire, more like 14, it's pretty small and flexible. Thanks for the info, I'll have to do some more checking.

[BruceMc]

When we had our 5er, the left front wheel would lock up on harder stops, but none of the rest would slide even when standing on the brakes.
Starting at the main lead near the wheels, I rewired the setup with 14 gauge wire using an equal length method. That means all four brakes had the same wire length between the main connect point and the brake pucks. From that point on, the LF never locked up, and it was actually a pleasure to tow afterward. All four wheels braked evenly, no pulling or locking. I wish I had done it not long after purchasing the unit.

I use a bit different connection method - I used ring connectors on each connect point, crimped, soldered and sealed with liquid insulation, then taped. Using small bolts, I connected each set of ring terminals and subsequently sealed and taped those connections.

[mrekim]

Is this a preventative maintenance item or are you trying to solve a brake problem? For example the controller is always at the max setting.

For preventative maintenance here are some things to look for:

1) Ensure crimps are good quality and sealed from the elements - just because they are factory does not mean they're good.... It's likely they are exposed to the elements and the wires will corrode over time, causing the connection to gradually get worse.

If the crimps are of the type where you can see the cut end of the wire and if you move the insulation side of the wire and can see wires on the cut side moving, then I would call that a "bad" crimp. That is also exposed to the elements....


I'm not convinced that wire nuts are good either.


2) Ensure there are no "extra" connections in the system - main run pieced together from smaller pieces (the only fix here is to re-wire).

3) Watch for problems with wire run through axle tubes (grommet rotted or missing for example)

4) Dexter and Lippert have a minimum wire gauge of 12 in the case where the axle is less than 30 feet from the hitch. It's 10 if the distance is more than 30 feet or for any tri axle trailer. Don't assume that the trailer manufacturer followed those minimum guidelines.

If you end up redoing the wire because of (#2 or #4) I would suggest at least 10 gauge as the main run.

The only way to make things worse is if you end up making bad connections and the brakes don't get the power they need.

[RCMAN46]

I have a Prodigy P3 controller. My brakes will lock up at about 7 volts on the Prodigy. That is about 60% of the available voltage. Increasing the wire size probably will do nothing as the controller will lock the brakes with the wire I have. Sending more current to the brakes will not accomplish anything.

The answer to your question, what voltage does it take to lock your brakes? If you are unable to lock brakes make sure they are in good condition no grease contamination and adjusted properly. If that is OK then a larger wire may give you more braking effort.