Winch battery wiring

[Broncohauler]

I'm putting a 12,000lb winch on the front of a car trailer ( the price was right) along with a battery. 

I want to use the 12v charge wire in the 7way plug to keep it charged. 

E-trailer diagrams show that a 12ga wire is good enough. But do I need some type of  Circuit breaker ?and if so what kind and what amperage ?

pictures or where to buy on Amazon would be great if it's needed. 

Thanks guys

[Yarome]

Unfortunately... and depending on the distance.. but assuming a 12' (24' run) distance, 10ga would be the absolute minimum in order to provide even a "maintanence" or "float" charge to a batter. If you wanted to actually replenish/charge your battery from a discharged state.. and assuming a 24' run (12' from source to battery) you would be looking more at a 5ga@5% loss (considered "adequate" by some) or more in the range of 2ga@3% loss.

Even with those guages it would be limited to a fairly light current (~30amps), but likely sufficient for charging a single 12v auto wet cell.

What you would need in between would depend on where you plan to run your source from, but you're probably looking at a solenoid and fuse at a minimum. 

What you are seeing on the E-trailer diagram is likely for a standard trailer 12v feed for running lights and other light, direct loads... Not intended for actual charging. 

[Yarome]

I should probably add that if your intention is to actually "charge" while driving.. the simplest installs I have seen have just been to leave your current 7way "as-is" and install a second independent plug for dedicated charging.

[forxlr8n]

Here was a size chart off of  Yellowbullet 

 

[Yarome]

4 minutes ago, forxlr8n said:

Here was a size chart off of  Yellowbullet 

Just to be aware... that chart reflects 19% losses at those guages. (see the fine print at the bottom)

[RandyA]

Yes, 12 AWG copper is "enough" to keep a charge on the winch battery on the trailer - but not heavy enough to fully recharge it in a reasonable amount of time.  My absolute minimum preference considering the distance the wire must be run from the alternator would be nothing less than 10 AWG copper - preferably even heavier.  Unless both the truck battery and winch battery are stone cold dead at the same time, the current on the trailer charge wire most likely isn't going to exceed 20 amps due to the combined parallel resistance of the two battery banks (truck and trailer).  The voltage drop for 25' of #10 AWG copper wire at 13 volts and 20 amps will be .51 volts.  With #12 AWG copper your voltage drop will be .81 volts.  As the battery charge rises the current will drop reducing the loss in the charge wire.  When the charge current drops to 5 amps in #10 AWG copper the voltage loss will be .1275 volts.  I am thinking you possibly already have #10 AWG copper in the cable from your truck alternator to the rear.   If you use the current 7-pin RV plug with a #12 hot charge wire from there to the winch battery the voltage drop will not be as great - but for recharging while driving do not expect the winch battery to ever reach a full charge - you will want to top it off with a wall charger when you get home (like your camper does with the converter/charger plugged into shore power).  BTW - I have a #6 AWG copper wire on my truck for the trailer battery(s). 

Now, all that said, if you are using a 12K electric winch expect the winch current to be extremely high -  as much as 200 - 250+ amps at full load!  You are going to need all the voltage your truck can provide from the alternator while running the winch to keep the winch battery from sagging too much.  You will note the instructions for the winch tell you to not only run the truck engine but bump up the RPM while using the winch.  For that purpose I would be running a separate pair of #2 to #0 AWG copper cables to Anderson connectors at the back of the truck with the plugged end going to the winch battery.  I would also advise having a large battery at the trailer - at least a group 27 or 29.   So, the big question for your purposes remains "What is enough?"

[Broncohauler]

Thank you guys for your help. 

I would like to use multiple trucks with this trailer, and that's why I'm hoping to get the 12v factory charge wire that ford, dodge and  Chevy have in the 7way. 

I know I'm limited to the power in the trailer battery and hope that's enough for just winching a car on?? 

but I want to make sure that I don't fry the truck or wiring by to heavy of a draw. 

E-Trailer says to unplug the 7way on a hard pull, but if the trailers loaned out I can't  guarantee that will happen and would feel bad if any truck was damaged. 

 Especially  mine if my son borrowed the trailer with my truck. 

[Broncohauler]

So what can I put in the trailer charge wire that will protect the tow vehicles from a heavy draw?

[Scrap]

You'd mount a Trailcharger at the trailer batts, probably just like the lift gate of your work trailer.  But they aren't cheap.  Does you son still work in parts?  It is a KW part #, maybe he can get a deal?

[Broncohauler]

Very good memory scrap. 

No after 5years at inland KW 

my son is traveling the world building million + gallon water storage  tanks mainly for the government. 

The last one is  a water thermal cooling tank for the new  Tesla manufacturing plant in Sparks Nevada. 

I do still have contacts though, my nephew is a tech there. 

[Scrap]

That sounds like more fun than a bunch of truck parts!  Have nephew look up a 11020C11.  It's the 12-12 charger used on the Clean Power trucks years ago.

[jkennell]

Explore the options at Waytekwire.com

A simple 20A breaker (correct size for 12g wire 10' long as per chart above) should protect the wiring.  Adjust the size based on your wire length and guage.  (20A may be lower than needed, but BSTS!)    https://www.waytekwire.com/item/46321/EATON-s-Bussmann-Series-121B20-A2P-KA-Shortstop/

You can use something like this, which is designed to do exactly what you are needed...boost voltage at a remote battery for charging.  https://www.waytekwire.com/item/80126/EATON-s-Sure-Power-11020C11-Trail-Charger-/   At $300 though....

[Broncohauler]

Ok thanks guys

[rpsinc]

Have you considered a solar panel permanently mounted on the battery box?  Sure have plenty of sun in Ramona.  I'm in Wildomar and its what I do instead of relying on charging ONLY when I use it.  A small panel is pretty inexpensive.  I would use at least a 10W.  I keep a 20W on my IH 4700 for maintenance.  Use a charge controller for sure, tho.

[Broncohauler]

That's a great idea. 

I know Home Depot has them on dump trailers they rent. 

[MrSeas]

Sure sounds like a "job" suited for a Lithium battery especially with the "high" draw ehen using the winch. Too bad it's on s trailer. Probably cost prohibitive!

[Broncohauler]

On 6/15/2017 at 0:23 AM, MrSeas said:

Sure sounds like a "job" suited for a Lithium battery especially with the "high" draw ehen using the winch. Too bad it's on s trailer. Probably cost prohibitive!

Ya a little to pricey 

[RandyA]

OK - I have a 12K electric winch that can mount either on the front 2" receiver or the rear 2" receiver on my 1 ton dually PU.  The truck has two group 24 batteries that can be put in parallel with a switch rather than the normal isolated pair.  The power cables are #2 AWG copper.  For front use the cables are 4' via an Anderson 200 amp connector.  If the winch is used on the back the cables that plug in are 24 feet.  Either way I can pull a rolling load that weighs as much as my Volvo up what I estimate to be a 4% incline if I use the snatch block for dual lines.  Yes, I have done it.  It will also pull the 4X4 dually out of a snow/ice filled ditch with a strap around a tree on the opposite side of the road.  Again, I've done it.  Pulling a Bronco weighing perhaps 4K pounds up a ramp onto a trailer is not going to make his 12K winch even hiccup - Broncohauler can probably do this with a single line easy as pie.  A smaller winch could actually need more amperage to get a car up the ramps than the 12K due to motor size and gearing.  Voltage boosters and Li-Ion batteries are nice accessories (I have them in my Golf cart) but he does not need them.  A good RV/Marine deep cycle group 27 battery will provide all the power he needs for the winch.  The issue is charging the battery from his tow vehicle.  If the winch/trailer is stored where something like a Battery Tender cannot be used it would be nice to have an 18 watt solar panel.  As for charging from the tow vehicle Broncohauler can "get by" with the black wire in a standard pigtail for a 7 pin RV trailer connector that is commonly used to maintain the battery's in a camper while traveling.  Despite what I wrote earlier he really does not need all the heavy wiring - what etrailer.com advised will work.  The battery on his trailer should, of course, have a connection to a break-away switch for the trailer brakes. 

I have a 16' flat bed trailer with dual axles.  The winch that I can mount on the front of the trailer is a Chinese Champion 4K model.  It can get hot but does the job of getting a car on the trailer.  The battery I use is a group 27 deep cycle from Autozone.  It also runs the electric tongue jack.  When towing it receives a charge from my GMC dually trailer connector which has a #12 wire in the pigtail to the trailer.   I do NOT leave a battery in the trailer.  I have it in a box and take it out so I can also use it as a trolling motor battery on my boat....or whatever I want a portable battery for.  When not in use it is float charged by a Battery Tender in an out-building.  It all works great.

Yes, I do have a heavier gauge wire from the alternator in the Volvo for battery charging to the 5iver.  But that is a different story as I am putting a charge into 4 golf cart batteries in the camper.

For Broncohauler's application, a 20 amp auto resetting circuit breaker like those used for headlights should be mounted between the charge wire on the car trailer and the tow vehicle battery charging wire.  On my Volvo I have a current switching relay similar to this one for the fiver battery charging line.  Well worth the cost for that application.  IMHO, HDT to 5iver wiring is more involved that what he needs for his car trailer.