Trailer Winch battery

[Ashful]

Any wisdom to share on batteries for electric winches? The application is dragging logs onto a 7000 lb. trailer, so we're talking maybe up to eight 40-foot pulls on 700 lb logs, or some mix thereof (eg. the odd 4000 lb. log).

Winch is rated 40 amps at zero load up to 340 amps at 7500 lb load, so although most seem to use light truck batteries, I wonder if this may fall more into deep cycle territory. It seems most deep cycle batteries are rated over 500 cold-cranking amps, which is less than half that of a typical light truck battery of similar size, but plenty sufficient for this winch. But, can they do 300'ish amps for an extended pull?

The odd thing is that, by the numbers, the deep cycles don't seem to get higher Reserve minutes or Amp-hour (20-minute method) ratings than equivalent-size light truck start batteries. Knowing this is the whole point of having a deep discharge battery, I'm guessing there's something I'm failing to recognize, here.

I have room on this winch mount for two Group 31 (i.e. large) batteries, but would rather just buy and maintain one, if it might have sufficient capacity. Rig will be setup to charge the battery(s) from the truck, as I drive to/from my logging site, and automatically disconnect from the truck when winch is enabled.

Thanks, guys.

 

[johneh]

Deep cycle batters are made to take a deeper discharge
and come back to a full charge than a reg. car/truck battery
They produce the same power but for a longer time before full discharge

 

[Ashful]

Deep cycle batters are made to take a deeper discharge
and come back to a full charge than a reg. car/truck battery

This part, I understand.

They produce the same power but for a longer time before full discharge

I do not think this is correct. They seem to be limited to lower current (and therefore lower power). I did expect them to have a higher storage capacity, but their 20-minute amp-hour and reserve ratings don't seem to show that. Check this example:

Note the 31XHD can do 1000 amps, versus the 600 amp rating of the 27MDCST deep cycle. You'd think this would come at a trade-off with reserve or Ah ratings, but they almost exactly the same.

 

[WoodyIsGoody]

Note the 31XHD can do 1000 amps, versus the 600 amp rating of the 27MDCST deep cycle. You'd think this would come at a trade-off with reserve or Ah ratings, but they almost exactly the same.

The starting battery can deep-cycle but it won't last very long if you regularly deep cycle it. That's the trade-off.

 

[Montanalocal]

I have a tailgate lift on my truck with a battery powered winch to operate it. It is connected to the vehicle battery. The instructions with this unit specifically state that one should keep the vehicle running while using the winch so as to keep the vehicle charging unit charging so as to help keep the battery up.

I am puzzled by the statement that your unit would "automatically disconnect from the truck when winch is enabled." I would think that staying connected and running during use would be a good thing. Am I missing something? (probably)

 

[salecker]

You can get a battery idolator that will charge you winch battery or your truck battery.It will charge whichever one needs it the most.With a little wiring you can have it charge whenever you are hooked up to your trailer.

 

[Ashful]

The starting battery can deep-cycle but it won't last very long if you regularly deep cycle it. That's the trade-off.

Good info. To be clear, is this something you just believe to be true, or do you have a reference for it? I run on hard data.

 

[Ashful]

I have a tailgate lift on my truck with a battery powered winch to operate it. It is connected to the vehicle battery. The instructions with this unit specifically state that one should keep the vehicle running while using the winch so as to keep the vehicle charging unit charging so as to help keep the battery up.

I am puzzled by the statement that your unit would "automatically disconnect from the truck when winch is enabled." I would think that staying connected and running during use would be a good thing. Am I missing something? (probably)

The wire running to the 7-pin connector on the back of most trucks today is not sufficient for running the winch, and you could quite easily cause damage if winching while connected. For this reason, it's best to buy or build a battery isolator, for this purpose. When that winch is running, it can pull 340 amps, and the vehicle wiring is likely rated 20 - 30 amps.

You can get a battery idolator that will charge you winch battery or your truck battery.It will charge whichever one needs it the most.With a little wiring you can have it charge whenever you are hooked up to your trailer.

I haven't found one that does what I'm looking for, which is basically to charge when the vehicle is powered, and isolate (enabling the winch) when the truck is not powered. By "powered", I mean that the 12V pin in my OEM connector is only live when the ignition is on, and that's when I want to disable the winch. Can you point me toward one that works like this? I was going to build my own (one NC relay, one solenoid), but would much prefer just buying something ready-made.

 

[WoodyIsGoody]

Good info. To be clear, is this something you just believe to be true, or do you have a reference for it? I run on hard data.

It's backed up by hard data. That's why they make two different kinds. I'm sure you can find the data if you're interested in it. It's well known that starting batteries are not well suited to repeated deep discharge.

 

[lsucet]

You should look into the chargers that they put now a day on dump trailers. Use a deep cycle battery and connect it to the charger. When connect it to the truck the 12 volts from the truck goes to the charger and the charger charge the deep cycle battery. Those chargers can also be connect it to 120 ACV to charge the battery. You just need an extension cord.

 

[Ashful]

It's backed up by hard data. That's why they make two different kinds. I'm sure you can find the data if you're interested in it. It's well known that starting batteries are not well suited to repeated deep discharge.

Of course. But it's also well known that deep discharge batteries don't like supporting high current loads for several minutes at a time. So, for a winching application, which is really worse?

I suspect the deep discharge is the way to go, but it's not what winch manufacturers typically recommend, so one has to ask why.

 

[Ashful]

You should look into the chargers that they put now a day on dump trailers. Use a deep cycle battery and connect it to the charger. When connect it to the truck the 12 volts from the truck goes to the charger and the charger charge the deep cycle battery. Those chargers can also be connect it to 120 ACV to charge the battery. You just need an extension cord.

Yeah, this seems to be the way to go! Looking at this system: (broken link removed to http://purkeys.net/boss-dump-trailer-charging-system/)

 

[lsucet]

Yeah, this seems to be the way to go! Looking at this system: (broken link removed to http://purkeys.net/boss-dump-trailer-charging-system/)

That is great. I have the system on my dump trailer it came with it. They are real small and compact. I am planning in the future, install a winch in front of my flat bed trailer and I will put the system in the toolbox. I just need to splice the 12 volts coming from the truck.

 

[lsucet]

I will also recommend to get one that can be connect it to 120 AC. Mine still small and compact, it has a converter built-in. That way you have ac/dc alternatives.

 

[WoodyIsGoody]

Of course. But it's also well known that deep discharge batteries don't like supporting high current loads for several minutes at a time. So, for a winching application, which is really worse?

I suspect the deep discharge is the way to go, but it's not what winch manufacturers typically recommend, so one has to ask why.

Deep discharge batteries can support high current loads when they are sized appropriately for the load. The best solution depends upon the usage profile. If you go big enough with deep discharge batteries you won't have to worry about stressing them with high current and if you go big enough with starting batteries you will not be cycling them as deeply. I'm not sure if anyone makes something in between a deep cycle and a starting battery in lead acid. Have you explored lithium ion? They are good at both deep discharge and high currents (and will be a fraction of the weight).

 

[Ashful]

Deep discharge batteries can support high current loads when they are sized appropriately for the load. The best solution depends upon the usage profile. If you go big enough with deep discharge batteries you won't have to worry about stressing them with high current and if you go big enough with starting batteries you will not be cycling them as deeply. I'm not sure if anyone makes something in between a deep cycle and a starting battery in lead acid. Have you explored lithium ion? They are good at both deep discharge and high currents (and will be a fraction of the weight).

The deep discharge I listed above is rated 675 CA, and I'm only drawing 40 - 340 A, depending on the load I'm pulling. So, it's rated for it, but it's not clear (to me anyway) how that load profile will affect lifetime or reliability. Probably fine, I'd guess.

I'm sure lithium ion would open up better possibilities, but we can't neglect cost. I'm looking at batteries that cost $100, and I suspect a lithium ion of similar current ratings would cost many times that.

 

[mustash29]

I am sorry to say, but if you plan to routinely work the winch that hard, you will quickly kill typical group 31 batteries, especially if you are not "trickle" charging them constantly from the truck. Winching a rolling car onto a trailer is a lot easier than dragging big logs.

You need to spend $$$ on a good large battery like semi's, front end loaders, etc use. You also need to keep the truck running and charging it. If your stock "trailer pin" is only capable of charging at 20 - 30 amps, then you need to install a current limiting device so as to not overload the trucks electrical system. The next step is to run a dedicated charging cable in the realm of 4 ga, 2 ga or bigger with "Anderson" style disconnect plugs rated for up to 350 amps. These are plugs similar to what is used on snow plows, electric forklifts, pallet stackers, etc. Then follow up with an upgraded alternator or dual alternators.

A better option would have been a gas motor, hydraulic pump and a hydraulic winch all mounted on the trailer tongue.

Several times I got tri-axel log truck loads delivered. 20' x 20" diameter oak. My process was to winch about 5 sticks off the top of the pile so almost 10 feet was hanging out in the breeze, then cut rounds, then split & stack nearby, repeat as necessary. I was using the Warn M-8000 on my S-10 ZR2. The stock 100 amp alternator was a piece of crap. When worked hard it would heat up and the output would drop off. It also only charged at about 40 amps at idle. When running this combo (stock alt, stock batt, winch) I could tell the system voltage was dropping off as the winch loaded up, and as the voltage drops current increases. This is how you overheat everything. Intermittent winching like this would kill the battery after about 30 minutes. Hooking up the 10 amp home charger helped somewhat. Keeping the truck running also helped, but it was hard on the rest of the electrical system. Keep in mind I was working the winch hard enough that I had to have the back of the truck strapped to a yard tree.

I upgraded to the largest Duralast Gold battery Auto zone sells that will fit in the stock battery tray. I upgraded to the AD-244 alternator. It is spec for a Tahoe / Silverado with the HD factory electrical system. It puts out 100 amps at idle and maxes out at 145 amps. It also has a larger cooling fan so it runs cooler. My duramax has the AD-244 stock. If you want heavy duty charging you can go with dual 100's or dual 145's.

I have an 06 Wrangler Unlimited that weighs roughly 4000. I has a Smittybilt 8000 on it. When I want to re-spool the cable on the drum properly I just winch the Jeep up the 10% grade in my driveway. Even with the Jeep idling, current draw is enough to stress out the stock electrical system, drag down the engine rpm's slightly and make the dash idiot lights go crazy.

I have 2 batteries in my garage that will eventually become the power supplies for a UPS based boiler overheat protection project. They are "discarded" batteries from my work that were used to start a 250 hp emergency diesel fire pump. They were out of date and no longer certified as "reliable" and had to be replaced. They are 3x the size of a normal car battery, 1150 CCA, 225 AH reserve @ 20 hrs.

 

[Ashful]

Good info, mustash29, thank you. But aren't group 31 batteries larger than your stock S10 battery tray, especially when I have room for TWO of them?

I checked the +12v pin on my truck's 7-pin connector today, and it's always hot. So, it will be charging all the time, if I use the dump trailer battery rigs. Not ideal, for avoiding a dead truck battery, but maybe I can figure a way around that.

The two dump trailer battery charger/isolators I've looked at so far both seem to run around 10 amps. If the winch is averaging 100 amps in the pull, and run at 50% duty, that's still a drain rate 5x higher than the isolator charge rate. But, I only need it to last long enough to load my small trailer, then it will have the entire trip home and back to recharge.

 

[greg13]

An easier way to reduce the amperage needed would be to use a snatch block and reduce the load pull by 50%.

 

[Ashful]

An easier way to reduce the amperage needed would be to use a snatch block and reduce the load pull by 50%.

You are correct... but this uses more energy, overall. The snatch block isn't without some associated loss, but even if we consider it perfectly lossless, you'd only cut the current by half the difference between full-load and no-load current. This is because winch draw is fairly linear versus load, between the no-load and full-load current points.

So, if I had a 4000 lb pull, it would average 197 amps without the snatch bock. With the block, it would average over 120 amps for more than twice as long. Unless I have a very fast charger, where it might keep up at this lower rate, I think it's overall worse for my battery situation.

 

[coaly]

Good info, mustash29, thank you. But aren't group 31 batteries larger than your stock S10 battery tray, especially when I have room for TWO of them?

I checked the +12v pin on my truck's 7-pin connector today, and it's always hot. So, it will be charging all the time, if I use the dump trailer battery rigs. Not ideal, for avoiding a dead truck battery, but maybe I can figure a way around that.

You need a Battery Isolator for charging. Mounts in engine compartment with one terminal to alternator and one to each battery. Each battery gets the proper charge rate keeping them separated.

 

[Ashful]

Yeah, that would be ideal. But in this case the battery and all circuitry must be on trailer, and I don't want to modify the wiring of every truck I might ever use to pull this trailer. That's why the dump trailer rig seems ideal, for this requirement.

 

[jetsam]

Yeah, that would be ideal. But in this case the battery and all circuitry must be on trailer, and I don't want to modify the wiring of every truck I might ever use to pull this trailer. That's why the dump trailer rig seems ideal, for this requirement.

Put a small charge controller next to the battery. They're small, cheap, and they are always come with flat surface mounts. It'll pay for itself many times over in extended battery life.

 

[Ashful]

Put a small charge controller next to the battery. They're small, cheap, and they are always come with flat surface mounts. It'll pay for itself many times over in extended battery life.

You mean, like a battery Tender? This trailer is normally stored several hundred feet from the closest electrical outlet. I'll have to settle for either letting it charge from the truck on my way to the job site, or hauling it over to my barn to charge the evening before use.

 

[WoodyIsGoody]

Yeah, that would be ideal. But in this case the battery and all circuitry must be on trailer, and I don't want to modify the wiring of every truck I might ever use to pull this trailer. That's why the dump trailer rig seems ideal, for this requirement.

I know you want a bad ass winch trailer. Here's what you do. Find an mount a used Powerwall 1 on that b-itch. Now you're styling. It has enough capacity to winch to your hearts content. might as well go whole hog and find some solar cells, probably wouldn't take many panels to keep it charged up in the down time. Don't worry about money, you're not gonna starve. You just want a bad ass winch trailer.