Winch wiring question (12V)

Anonymous Poster · Dec 10, 2002

Gary, I highly recommend installing a battery disconnect switch right at or near the battery. More vehicles burn for the want of a $25- switch than should.
I just had to replace the "automotive type" winch cable running to an electric crane on the back of a truck I bought cause it constantly drew the battery flat sitting overnight.

gws · Dec 10, 2002

Re: Winch wiring question (12V)

One issue I see is the plugs. The male plug should not be on the source voltage side (battery). This will usually leave exposed postiive voltage that could come in contact with the frame ground. Source should be female.

You can charge the trailer battery off the truck, but you should consider getting a battery isolator to keep back feeding and over charging.

dummy · Dec 10, 2002

Late reading this and it's a little confusing. The breakaway battery on my trailers are already wired into the accessory side of the wiring harness. As long as the truck is plugged in, they get charged through an isolation circuit. I assumed this was a standard design with the breakaway kits.

dummy · Dec 10, 2002

Meant to add a picture to the previous. The box in the lower left corner is the charger/isolator circuit.

TWINKLE_TOES · Dec 10, 2002

What do you think is inside of those fancy overpriced isolators?

One or more diodes. What I'm saying is they don't keep the Aux battery charged to it's full capacity.
If you would research this a bit I'm sure you will find this to be true.

Gary_in_Indiana · Dec 10, 2002

"I highly recommend installing a battery disconnect switch right at or near the battery"

I'm thinking just unplugging the winch from the battery will accomplish the same thing for about $25 less. /w3tcompact/icons/clever.gif

I think I may well need ot clarify a few things here. I don't intend to leave the winch on either the trailer or on the back of my truck unless I'm using it so it'll only be connected to battery power then.

The trailer sits far more than it moves so the idea of hooking up to it AND then connecting the trailer battery to the truck battery had some appeal so I could charge/top off the trailer battery that way for it to operate the hydraulics on the tilt bed even if I don't ever put the winch on.

Odds are I'll only use the winch for "dead" vehicles and will just drive the others on. I just thought that it'd be like running jumper cables between the battery on the running tow vehicle to the trailer battery to charge it or, in a worst case scenario, to power the hydraulics motor through the trailer battery in a pinch. Does that make any sense?

Anonymous Poster · Dec 10, 2002

If I'm reading what youre writing right, I'd opt to save a lot of time wiring the truck, and get myself a 30 foot set of plug in jumper cables to run back to the trailer when needed.
If the distance you'll be towing the trailer justifys it, I'd equip the truck with a #12 wire running from the ignition terminal to the battery on the trailer via the trailer plug to top off the trailer battery in route. I'd also equip that line with a 20 amp circuit breaker and a DIODE to prevent backflow from the trailer to the truck. Then again, what do I know, I've only been building equipment for 41 years effective Friday the 13th.

TWINKLE_TOES · Dec 10, 2002

Franz,

You can lead a horse to water......

Anonymous Poster · Dec 10, 2002

Twinkle my man, I'm an old fart who has been doing it for a lot of years, and unless and until you can show me where the diode in an expensive battery isolator delivers one bit more power downline to a battery than a single diode does, this horse ain't gonna drink or swim, let alone do the backstroke.
Right now I'm running several vehicles with lantern chargers, my service truck where the generator battery is charged thru a diode, and a few trailers that maintain their batterys via a diode, as well as handlanterns that charge thru a diode, and have yet to have a problem. Then again, I'm old enough to remember when a 5u4 vacuum tube was called a valve on one side of the Atlantic because it acts like a check valve to electricity.
When something works 100 0r more times, I'll take a lot of convincing it doesn't.

TWINKLE_TOES · Dec 11, 2002

Good response /w3tcompact/icons/smile.gif

unless and until you can show me where the diode in an expensive battery isolator delivers one bit more power downline to a battery than a single diode does, this horse ain't gonna drink or swim, let alone do the backstroke.

Nope, not going to do that, isn't any difference. The point was, a diode in the line only allows the battery to charge to ~ 50% of it's capacity whether it be from an expensive battery isolator or from one you might add. For the winch application this don't work. Your application sounds significantly different than a winch that wants to draw 400 plus amps plus under load.

To understand why, you need to examine the charge source and the battery chemistry. A modern alternator is a single wire device with internal voltage regulator. The regulator output voltage will vary from ~13.8 volts to ~14.4 dependent on the connected loads and the battery charge current demand. The automotive battery has a pretty easy life, supply high current during starting and after that the alternator supplies the connected loads. In normal operation the auto battery depth of discharge is only slight.

The auxillary battery will typically see a deep depth of discharge and deep cycle batteries are appropriate. The chemistry of the lead acid battery under charge will cause the terminal voltage to gradually increase until it reaches a transisition voltage of ~13.8 voltage, at which time it rises abruptly. High current charging above this potential will boil the electrolyte away. At the transisition voltage the battery capacity is ~50%. The alternator continues to supply reduced current to the battery until the voltage reaches~14.2-14.4 volts.

The following table (battery manufacture unique) is typical of the terminal voltage and state of charge for a battery that has been rested for 48 hours:

100% 12.80
75% 12.60
50% 12.40
25% 12.20
0% 12.00

You can see from this that the terminal voltage difference between a full battery and an empty battery is only 0.80 volts.

I you now subtract the forward diode drop 0.7 to 1.0 volts (dependent on forward current) from the requlator output 13.8 -0.7 = 13.1 V and 14.4-0.7 = 13.7V, you can see that the Auxilliary battery never gets above the transisition voltage for lead acid of 13.8 volts.(~50% capacity)

Some isolators use Schottky diodes with lower forward voltage drops (0.4 to 0.6 volts)at the expense of high reverse leakage and lower breakdown voltage, but the payback is small and there are better ways to work this problem.

older alternators with remote requlators can be rewired to compensate for the diode drop. Several manufactures offer adjustable regulators and dual output requlators in addition to smart (three state regulators) Battery combiners (voltage sensing switchs) are also offered.

What were the five tube types in the universal AC/DC superhetrodyne receiver?

Gary_in_Indiana · Dec 11, 2002

"I'd opt to save a lot of time wiring the truck"
Franz,

I'm definitely not going to let the guy who does my wiring read that. /w3tcompact/icons/smile.gif

There are reasons I want wiring from the truck battery to the back of the truck which have nothing at all to do with the trailer. The winch is on a platform with a receiver hitch insert. There will likely be times when I simply want to attach the winch to the truck without the trailer involved at all. Additionally, there may be a situation wherein I want to use the winch with a tow dolly. As the dolly has no power source, I'll need to power the winch from the truck battery.

I guess the point I'm trying to make here is that the wiring from the truck battery to the back of the truck should be looked upon as a given. If (who am I kidding? WHEN) I run into a situation where I have a dead trailer battery, I can just run from the back of the truck to the trailer battery to power the hoist and the winch. Wouldn't that be effectively the same as powering the winch and hoist off the truck battery directly? I know it wouldn't 'charge' my trailer battery but I could then worry about charging the trailer battery when I get back home. /w3tcompact/icons/smile.gif How does that sound?

Anonymous Poster · Dec 11, 2002

Well Gary, I'm lookin at it thru Neuevo Hillareah eyes, formerly NY, and I really can't comment on the corrosiveness of Indiana air, but here, we get all the downwind contamination from the rest of the country, so we do a lot of rewiring on equipment. I can strip insulation off the wire in a 6 month old truck and the wire will be green.
On top of that, any wire you run under a truck will ABSOLUTELY find every sharp spot on and along the frame, and chew insulation off on that sharp spot.
I've got a pretty good idea what you're trying to accomplish, one of my buddys has a winch setup that plugs into his receiver, and then he hauls the trailer from the back end of the winch. (I'm not going to comment on the dynamics of that setup)
A lot of experience with electric winches has convinced me the clocer they are to the battery they are operating from, the better they pull. Most winches suck more current than a starting motor on a big block, and do it for longer.
I set one up on my car trailer 20 years back that had 3/0 welding cable running from the battery to the winch, and it didn't run worth crap. I added a battery onto the toung of the trailer, and the winch performence doubled.
There are a lot of questions you need to answer before you set something like this up.
1) How often will you change towing trucks?
2) Will you tow with multiple trucks?
3) how far do you go out before you use the winch (charging)?
4) How often will you use the winch?
5) How regularly will you use the winch without the trailer?
6) How long will you keep the truck after you go thru all the setup?
7) Is there an easier/ cheaper/ more useful way to do it?

If you do run any kind of heavy cable along a truck frame, pull it thru an old hose for protection, and have a disconnect as close to the battery as possible.
Since you already have a battery on the trailer for the hydraulic pump, how are you charging that one? Wouldn't a long set of jumper cables (plug in type) be more cost effective?
If you know a forkilft dealer you can generally get battery plugs free from junk batterys.

Gary_in_Indiana · Dec 11, 2002

Franz,

Your questions gave me a lot of food for thought here. I've had to change a couple of my earlier answers based on a later question. I needed that kind of Q & A. Thank you.

Here are my answers as of this time and date (all subject to change as this progresses). /w3tcompact/icons/smile.gif

1) How often will you change towing trucks?
VERY seldom. I generally keep one a couple years.
2) Will you tow with multiple trucks?
No, unless mine is down and I need to at that time. It's not a likely scenario at all.
3) How far do you go out before you use the winch (charging)?
The "long" trip would be a couple hours. Honestly, after all I've read here about the 'charging' aspect, I think I may just avoid it altogether.
4) How often will you use the winch?
I'm not sure. It has a brake so I may use it as my front tie downs which would translate into every time I use the trailer running the winch a couple feet in or less. Now that I think about that, if I'm going to do that, I may as well use it even on the driveable vehicles rather than drive them up there and then climb out on a snowy or icy angled steel bed. /w3tcompact/icons/clever.gif
5) How regularly will you use the winch without the trailer?
Again, not very often.
6) How long will you keep the truck after you go thru all the setup?
Tough call. I like my Tahoe but would go with a K-2500 Suburban if the right one came along. /w3tcompact/icons/wink.gif It would actually be a better match for this trailer than the Tahoe is. /w3tcompact/icons/smile.gif
7) Is there an easier/ cheaper/ more useful way to do it?
Easier? Not doing it would be the only way I can see that would be easier. Cheaper? Most everything I need for this is already in the shop here and the bulk of the rest will be cheap or free. More useful? I'm not sure what you mean here. If it's "more effective/better," then I don't think there really is one that offers the utility to do all I want unless it would be to run a plug out through the grill then just use the cable I was going to permanently mount underneath as an "extension cord" from there to the rear when I need power there from the truck battery.
Since you already have a battery on the trailer for the hydraulic pump, how are you charging that one?
Battery charger at the shop.
Wouldn't a long set of jumper cables (plug in type) be more cost effective?
It would except for poor trailer design which placed the battery under the bed making the terminals accessible when the bed is raised ONLY! Obviously, if the battery is dead, the bed won't raise to expose the terminals. /w3tcompact/icons/hmm.gif I suppose I could wire out to a terminal block extension in addition to the plug I'll already have there for the winch.
If you know a forkilft dealer you can generally get battery plugs free from junk batterys.
That's exactly where I got the extras I needed. /w3tcompact/icons/wink.gif/w3tcompact/icons/clever.gif/w3tcompact/icons/grin.gif

Anonymous Poster · Dec 12, 2002

Gary, If I was doing what you say you want to accomplish, I'd go about it as if it were a christmas tree lighting situation.
Think of the truck as the power source, and put a female plug on the grill, like tow trucks do.
Make up a 30 foot cord that plugs into the truck.
Put a male plug on the trailer battery connection, and a female.
Plug the trailer battery into the cord coming from the truck.
Plug the winch into the female coming from the trailer battery, and work the system. Just remember the truck should be running when winching.
If you add another winch mount to the front of the truck, you already have power at the grill. If you tow the trailer with another truck, you have power for winching.Onliest thing you gotta do with the truck is hook up 2 wires to the battery.

Gary_in_Indiana · Dec 12, 2002

That's just about what I'd come up with after reading through your questions (and my answers). There's one other thing I'm going to add to the mix, too.

I think after I have all of the wiring done I'll get a pair of clamps and run a very short length of cable to yet another plug. With that I can then use my long extension cable as a jumper cable set by just plugging the clamps into the open end. /w3tcompact/icons/clever.gif

Thanks again for all of your input. /w3tcompact/icons/smile.gif

chim · Dec 12, 2002

Just be sure to get "manly" clamps. The last set of jumpers I bought were real heavy duty, but often would not start a "dead" vehicle without first connecting and giving it some time to charge up. I couldn't locate better clamp ends, so I replaced them with 4 Visegrips. Absolutely amazing difference. If they won't pass enough current from the donor vehicle to spin the starter of the dead vehicle, the factory ends would never supply the amps needed for a winch under load.

Winches take a whole bunch of those little electons to make the motor spin under load. I was using my Warn 8000# to pull out some old temporary cable when we got the permanent service up and running. The runs were several hundred feet of (3) 500MCM copper each, and there were 3 runs. To get them moving, I had to use a snatch block and double-rig. Winch was mounted in bed, so front of truck was chained to a (full) dumpster. We rehooked after pulling about 50 or so feet at a time. When we had a fair amount of cable pulled out, it began to pull easy enough to pull single-line. Not needing the dumpster for an anchor, I moved the truck farther away so we could pull close to 150' at a whack. It wasn't making sense - the winch motor went slower and slower. Eventually the winch stalled with the truck was parked in the grass. I've slid the truck on dry pavement without stalling the winch before when the drum was nearly empty. There was a lot of noise (construction site) and I never noticed the truck engine had stalled. The truck needed a jump start to get it going again. Too much winching, and not enough charging time.......................chim

Anonymous Poster · Dec 12, 2002

Couple things here, Gary, get yourself some welding ground clamps and saw off the longer end so you have good jumper clamps. I run them on my Startall, and they do the job nicely.
I also have a set that plug into the jumper plug on my Dodge M-37. Side terminal batterys are a PITA, but since they are generally on TonkaToy sized vehicles, you can hold them in place, or buy a set of copper strap adaptors.
Chim, I can guarantee you even a 100 amp alternator won't support an 8000# winch in steady operation. If you have access to a digital amprobe type meter you can get a good idea of what that winch is sucking out of the electron box.

chim · Dec 13, 2002

Franz, 10-4. I was attempting to make a point of how much current is needed to run such a piece of equipment. On a long and difficult series of pulls, there should be periods allowed for the battery to get snacks from tha alternator. I was pushing it, and the winch took power from the battery faster than the 60A alternator had any hope of replacing it.

The winch motor is a 4.5HP series-wound affair. Such a motor develops tremendous torque (at a cost of tremendous amperage). Both torque and amps peak as it stalls. I never measured it, one reason being my clamp-on is AC and my DC measurement capability is limited to two digits. I guess the thing pulls somewhere in the neighborhood of 300A or so based on the HP at 12VDC. No idea what the efficiency is.

I know people who are impressed by ads that proclaim "Heavy Duty Jumper Cables" and don't even pay attention that the package lists wire size as small as #8. If it says "Heavy Duty", the jumpers gotta be great, right? So far what I've seen is that even on the better jumpers, the clamps are the weak link. That's how I ended up with Visegrips for clamps.

There may be some good factory ends out there I haven't seen, but the "sheet metal clothespins" that usually grace the ends of the cables simply don't contact enough area firmly. Asking such a connection to do a few hundred amps for more than a couple nanoseconds becomes a lesson in current flow through a resistance...................chim

Gary_in_Indiana · Dec 13, 2002

I agree with you on the "manly" clamps. There's a supplier around here who has some really nice, heavy ones that are used with tow truck jumper cables so I'll probably go with those or the welding style.

I have the same Warn 8000# winch you mention and agree that it would take a lot to power it for very long. I'll probably be relying on my 1000 amp marine deep cycle/starting battery on the trailer most of the time but do have a 1000 amp battery under the hood as well. I figure if I get to the point where I'm running both of those down it's time for to call for bigger equipment. /w3tcompact/icons/smile.gif

BTW, I checked with my local marina regarding the charging of marine batteries through the trailer plug and no one there had ever heard of it, though they agreed it could probably be done so there was no help there at all.

bgott · Dec 14, 2002

My last travel trailer had a marine deep cycle battery on it and it charged through the plug just fine. As a matter of fact, all modern RVs run deep cycle batteries in them. Talk to an RV supply for the best way to rig it.