Trailer wiring help

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wirenut

wirenut

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Hi All,
I have a new trailer that I have installed a winch on, and a batter to power it. My question is;
The truck (2014 ram 2500) has a terminal in the trailer plug connector that seems to be a 30a circuit back to the fuse box. If I continued that power feed from the connector to a mechanical 30 min. twist timer, and then to the battery, could I feasibly, (without damaging the truck) charge the battery when it gets low? Rather than have to always have a gen and battery charger on hand?
 
I would not bet on it.

You have to realize the situation you can get into in a deal like this. Let's say you just got done on a nasty job. Maybe you broke the rear axle. Maybe the front suspension got damaged. In other words, you just loaded "the car" and it REALLY took some pullin.

So the winch has REALLY used the trailer battery, and now it's REALLY pulled down.

That battery is really going to want to "suck" current on that 30A line. It might warm things up, and it might blow the fuse.

Not knowing just how good that line was wired I'd probably want something I knew was "a little better" such as minimum no8 or better no6, and put a giant "max fuse" in there

"Charts vary" but 50A for no 8, 80A for no6

I would take a GOOD look at the under-hood alternator wiring before deciding where to tie in "up front."

Also bear in mind that along with hooking up the trailer "charging line" you are going to want the GROUND upgraded as well. A dedicated no6 from the trailer frame / trailer battery NEG direct to your pickup frame would be good, but I don't know "how" you would pull that off

Perhaps some of the quick connect welding cable connectors?
 
I use a snowplow connector. But I ran a no 6 back the frame and tied it to the truck battery. I do not have a battery on my trailer for the winch. And I also have another trailer that is a dump. I use the same connector to run it when am hooked to it. But 67dart273 makes me question that hookup because I run it off of the truck battery. And he sounds far more knowledgeable than I. And when I am using my winch or my dump I leave my truck running. Here is an ebay link to the connectors...I think.

[ame="http://www.ebay.com/itm/QUICK-CONNECTOR-KIT-175A-RED-WINCHES-SNOW-PLOW-TOWING-4X4-QUAD-SALT-TRUCK-/130814064036?pt=LH_DefaultDomain_0&hash=item1e752035a4"]Quick Connector Kit 175A Red Winches Snow Plow Towing 4x4 Quad Salt Truck | eBay[/ame]
 
Why not just run a cable off the battery with a disconnect?
 
dartnabout said:
I use a snowplow connector. But I ran a no 6 back the frame and tied it to the truck battery. I do not have a battery on my trailer for the winch. And I also have another trailer that is a dump. I use the same connector to run it when am hooked to it. But 67dart273 makes me question that hookup because I run it off of the truck battery. And he sounds far more knowledgeable than I. And when I am using my winch or my dump I leave my truck running. Here is an ebay link to the connectors...I think.

http://www.ebay.com/itm/QUICK-CONNE...036?pt=LH_DefaultDomain_0&hash=item1e752035a4
Click to expand...


That is the same type of connector that electric forklifts use. One of my tow trucks use them to connect jumper cables up when jumping another vehicle. It is sweet since you don't even have to raise the hood on my wrecker.

http://www.ebay.com/sch/i.html?_trk...forklift+battery+connector&_sacat=0&_from=R40
 
Thanks all for the insight. I will likely just charge the batt when low. Seems simpler. I only put the battery on board the trailer so if I needed to use the winch while not on the truck I could.
 
On my jeep I used a battery with both top and side posts.
The jeep has factory top posts.
Hooked the winch leads to the side posts.

Just an idea.
 
We bought a Pierce Carriage car trailer. It is a hydraulically controlled sliding axle trailer that doesn't need ramps because the tail end of the trailer drops as the axles are pulled forward. It has it's own hydraulic pump and battery. The literature that we got with it had us tie our tow vehicle battery source to the trailer to keep our trailer battery charged. It has worked fine for us for years. If the trailer sits for months at a time we still have to recharge it. But once charged the truck will maintain the trailer battery. When we've used it behind vehicles without the extra 'charging' wire we tend to have insufficient power when we need it.
 
X2 on using an Anderson Power Plug for charging a battery like this. The charge wire in the typical 7 pin RV trailer connector is too small to be of any use. I used an APP connector to connect our camper to the truck. Can get them from Grainger, powerwerks, or West Mtn Radio to name a few vendors. I used 6ga. duplex wire from West Marine.

I'd also give some thought to installing a VSR/ACR between the batteries. A "Voltage Sensing Relay" or an "Automatic Charge Relay" make sure that the starting battery gets recharged first, and then connects the trailer battery for charge. When the charge source stops for any reason the ACR/VSR disconnects so that you don't draw down the starting battery. Del City linked above carries the excellent BEP Marine product under "Specialty Relays". Unless the trailer is going to have solar AND you want that solar to charge the tow rig's battery you want the "Single Sense" version.
 
I have dealt with RV's and towing trucks for quite some time, and a lot of towing trucks have a battery charging (power source) circuits built into the wiring.
If I remember right it's a large black wire. (keep in mind that RV's use black for positive and white for grounds.)

Some vehicles use a ford type starter relay so it disconnects from the remote battery when the towing vehicle is not running, but activates the relay when started so it charges the remote battery.

My point is, that a lot of tow capable vehicles are wired for charging your trailer or RV batteries already. (through the existing trailer plug wiring)
I used to install the remote charging systems on vehicle that didn't have it.
 
The problem, as I see it, with the OE tow vehicle charging wiring is that the wire is too small for the length of the run (have to include the return or ground length as well). Results in excessive voltage drop and the trailer battery never really gets fully charged. When that happens the trailer battery doesn't live very long and performs poorly during it's life.

The max wire size that any RV light plug that I've seen will accept is 10 ga., and that's usually for the electric brake circuit not the charging circuit.

When looking at this sort of thing it's really easy to find ampacity charts for AC, but DC is different, it's ampacities in a given gauge will be lower since AC has a cooling effect due to it's cyclic nature. Look at this chart:
http://www.polarpowerinc.com/info/appendix.htm#Table C-2
Note that it is for one-way so it's 30 foot length limit of 3.5A in a 10 ga. wire would be only a 15 foot run. Which is shorter than most trailer charging distances. That's for a 2% voltage drop, which isn't a lot until you consider that a 2% VD drops the charging voltage to 13.33 volts if it was the usual 13.6VDC alternator output (some go to 14.4VDC). There needs to be a charging differential, the charging voltage has to exceed the battery's standing voltage by some amount in order to charge the battery. As soon as the charging voltage isn't high enough, charging basically stops. That seemingly tiny voltage drop in the too small of a wire just short changed the trailer battery from getting a full charge.

The reason to run a large gauge cable for trailer battery charging isn't because you're going to be pumping 100 amps thru it. The reason is to have the tiniest voltage drop reasonably possible.
 
ntsqd said:
The problem, as I see it, with the OE tow vehicle charging wiring is that the wire is too small for the length of the run (have to include the return or ground length as well). Results in excessive voltage drop and the trailer battery never really gets fully charged. When that happens the trailer battery doesn't live very long and performs poorly during it's life.

The max wire size that any RV light plug that I've seen will accept is 10 ga., and that's usually for the electric brake circuit not the charging circuit.

When looking at this sort of thing it's really easy to find ampacity charts for AC, but DC is different, it's ampacities in a given gauge will be lower since AC has a cooling effect due to it's cyclic nature. Look at this chart:
http://www.polarpowerinc.com/info/appendix.htm#Table C-2
Note that it is for one-way so it's 30 foot length limit of 3.5A in a 10 ga. wire would be only a 15 foot run. Which is shorter than most trailer charging distances. That's for a 2% voltage drop, which isn't a lot until you consider that a 2% VD drops the charging voltage to 13.33 volts if it was the usual 13.6VDC alternator output (some go to 14.4VDC). There needs to be a charging differential, the charging voltage has to exceed the battery's standing voltage by some amount in order to charge the battery. As soon as the charging voltage isn't high enough, charging basically stops. That seemingly tiny voltage drop in the too small of a wire just short changed the trailer battery from getting a full charge.

The reason to run a large gauge cable for trailer battery charging isn't because you're going to be pumping 100 amps thru it. The reason is to have the tiniest voltage drop reasonably possible.
Click to expand...

So although I'm charging my trailer battery through the trailer connector I'd have a much more efficient system if I ran a separate heavy charge wire. Good to know. The setup I have now works but takes forever to recharge my battery if it's low. That's why I occasionally have had to use a battery charger after the trailer has sat for extended periods.
 
TrailBeast said:
Some vehicles use a ford type starter relay so it disconnects from the remote battery when the towing vehicle is not running, but activates the relay when started so it charges the remote battery.
Click to expand...

Partially true. You do NOT want to use a "starter relay." You want to use what is specifically rated and is in fact called a "continuous duty solenoid." An actual Ferd relay won't last long.........perhaps 15 minutes...........before it gets hot and burns up

This is because the coil in a Ford relay is much heavier and draws more current. The reason for this is the current rating on the contacts. "Part of" the engineering behind the current rating on relay / switch contacts is the surface area and the PRESSURE EXERTED on the contacts.
 
67Dart273 said:
Partially true. You do NOT want to use a "starter relay." You want to use what is specifically rated and is in fact called a "continuous duty solenoid." An actual Ferd relay won't last long.........perhaps 15 minutes...........before it gets hot and burns up

This is because the coil in a Ford relay is much heavier and draws more current. The reason for this is the current rating on the contacts. "Part of" the engineering behind the current rating on relay / switch contacts is the surface area and the PRESSURE EXERTED on the contacts.
Click to expand...

I got some PRESSURE for ya. :D

I used the words "ford type" for the visual part, but thanks for the added info.
 
Can somebody do a wiring schematic for whatwe are talking about. I have the two 06wire One red one black ran from my tow vehicle battery back to the rear bumper and into my Anderson disconnect. I do not use a trailer battery for the winch or the hydraulic pump. How do I need to be hooking this up? Where do I get a "continuous duty solenoid" and how would I hook it up? It sounds like I have been fortunate NOT to have burnt anything up. And I don't want to give Wirenut bad advice.
 
Cole-Hersee makes continuous duty solenoids. They're a three wire hook-up; power in, power out, and ignition source.

The ACR's or VSR's are also a three wire hook-up; power in, power out, and ground. I like these better than a continuous duty solenoid because they're smarter about when they make and break the connection (allows the starting battery to be recharged before connecting, disconnects automatically when the alt stops charging), but they do cost a bit more than the solenoids do.
$96 http://www.delcity.net/store/Voltage-Sensing-Relay-!-Single-Charging-System/p_793852
vs.
$25 http://www.delcity.net/store/Solenoid-Switch-!-100A-@-12V-Grounded-Continuous/p_790161
 
If those are halfway decent quality, that's a good price on a continuous duty solenoid
 
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