Litium batteries for winching

nickburt

Observer
Just in the process of a re-vamp of my battery set up and have changed my house batteries over to lithium (2x 100Ahr Renogy).
My starting battery is a 110Ahr lead acid.
My winch is powered by the house batteries, but now thinking I need to power it from the main starter battery, due to the potential current draw by the winch being too much for the 2x 100Ahr lithium house batteries.
Would also be nice to swap out the main battery for a lithium, but, as above, I think I need to power my winch from a LA or AGM ?

Any experience using lithium for winching? Or source/manufacturer of a lithium that can withstand the current draw of a winch?
 

Montereyman

New member
A lot depends on what is available to charge the lithium batteries as the standard voltage regulator in a truck is designed for charging FLAT or AGM batteries which will be at a lower voltage.

I would put a starter battery with the greatest CCA capacity possible that will fit in the existing battery tray. I bought a Optima Yellow Top H7 size battery with 880 CCA and 80 Ah. It is also a marine type battery that can better withstand deep discharging than the usual starter battery.

How much do you actually use the winch? When I have had them on my trucks I found that 100% of the time it was to pull out some clown who got stuck through sheer stupidity.
 

chet6.7

Explorer
How many amps does your winch pull vs how many surge amps the lithium batteries can deliver. I am pondering this as well. Will Prowse youtube channel surge tested the
LiTime Trolling Motor Battery.
 

Mickey Bitsko

Adventurer
I would think regardless of battery composition you will still have to run a charging system, unless you have multiple batteries, even they will last only so long.
 

Hnoroian

Observer
What winch, and intended use on what? You said house batteries, so assuming toy hauler or roof rack boat holder, etc…
 
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nickburt

Observer
Thanks all for the replies.
Winch is a 12000lb champion, front bumper mounted for vehicle recovery. Used very little - and as said above - used more often for pulling others out than self recovery.
Current starter battery is charged by a standard alternator, so if I were to go lithium, a B2B charger (or similar) would be needed to get the correct charge algorithm.
House batteries - just a way of saying auxiliary batteries for onboard power other than starting and running the vehicle (Land Rover 130). These (2x 100Ahr) are charged using a B2B charger.

Think I'll just re-wire the winch to run off the starter battery only.
My lithium auxiliary batts have a max discharge current of 100A, with a warning at 110A, primary protection at 130A and Secondary protection at 130A - winch could pull more than this.
 

DaveInDenver

Middle Income Semi-Redneck
It's not that lithium can't be used for high current. It most certainly can.

The problem is managing them thermally. They need to be kept from going into high temperature runaway and melting down. So you need to find cells for continuous (not just surge) high current and a BMS that will be compatible.

It exists. It's not cheap and going lithium at all still carries a cost premium.

For example look at what one brand, Dakota, offers.


They have a 60 A-hr starting capable battery for $600 and a deep cycle only 54 A-hr for $399. The deep cycle on can do 60A sustained, 100A peak for 10 seconds. The starting one 100A continuous, 750A for 2 second or 650A for 5 seconds. The cells may actually be the same or similar but the BMS to control one is larger and more complex, which is probably the majority of the cost.

So you can see even a "dual" use still won't safely run a winch. You'll be somewhere between those two ends, perhaps 150A to 300A for 10 seconds or 60 seconds. It's hard to really characterize exactly what a winch load might be other than to say you have an unloaded spooling drawe (say around 75A, give or take) up to a locked rotor draw (generally about 350 to 500 amps depending on size) that could range pretty widely in duration.

So what you might use for ideas is look at what off grid users do to build lithium banks for running inverters. They usually manage thermal by first using a higher voltage to keep current down to meet a power need. If you need to feed 4800 watts (400A draw in a 12V winch) going to a 48V bus automatically drops your current compared to 12V by a factor of 4. At 48V that 4.8kW load will be reduced to 100A, a much more manageable current.

They're putting 16 cells in series to do this. We could do something similar by putting 4 strings of 4 cells in parallel. It's still 16 cells but you could keep the individual cell currents reasonable, but the cost of cells and BMS has gone up.

Balancing becomes a headache, too. The BMS will do it's best but the typical way BMSes work is to assume topped cells to start and have very small (a few milliwatts) bleed resistors to keep them balanced. This works fine in a 4S arrangement just fine but in a 4P4S that you rapidly charge and discharge the cells need active balancing and probably periodic maintenance to prevent losing capacity fast.

At this point with 12V winches the option to use lithium is likely to be tough practically and for a reasonable price.
 
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nickburt

Observer
It's not that lithium can't be used for high current. It most certainly can.

The problem is managing them thermally. They need to be kept from going into high temperature runaway and melting down. So you need to find cells for continuous (not just surge) high current and a BMS that will be compatible.

It exists. It's not cheap and going lithium at all still carries a cost premium.

For example look at what one brand, Dakota, offers.


They have a 60 A-hr starting capable battery for $600 and a deep cycle only 54 A-hr for $399. The deep cycle on can do 60A sustained, 100A peak for 10 seconds. The starting one 100A continuous, 750A for 2 second or 650A for 5 seconds. The cells may actually be the same or similar but the BMS to control one is larger and more complex, which is probably the majority of the cost.

So you can see even a "dual" use still won't safely run a winch. You'll be somewhere between those two ends, perhaps 150A to 300A for 10 seconds or 60 seconds. It's hard to really characterize exactly what a winch load might be other than to say you have an unloaded spooling drawe (say around 75A, give or take) up to a locked rotor draw (generally about 350 to 500 amps depending on size) that could range pretty widely in duration.

So what you might use for ideas is look at what off grid users do to build lithium banks for running inverters. They usually manage thermal by first using a higher voltage to keep current down to meet a power need. If you need to feed 4800 watts (400A draw in a 12V winch) going to a 48V bus automatically drops your current compared to 12V by a factor of 4. At 48V that 4.8kW load will be reduced to 100A, a much more manageable current.

They're putting 16 cells in series to do this. We could do something similar by putting 4 strings of 4 cells in parallel. It's still 16 cells but you could keep the individual cell currents reasonable, but the cost of cells and BMS has gone up.

Balancing becomes a headache, too. The BMS will do it's best but the typical way BMSes work is to assume topped cells to start and have very small (a few milliwatts) bleed resistors to keep them balanced. This works fine in a 4S arrangement just fine but in a 4P4S that you rapidly charge and discharge the cells need active balancing and probably periodic maintenance to prevent losing capacity fast.

At this point with 12V winches the option to use lithium is likely to be tough practically and for a reasonable price.
Thank you. Very similar end result to my current train of thought.
For the amount it "might" get used for (assuming I don't do something stupid!!!) I've come to the following conclusions:
1. Swapping out the starter battery for Lithium and all that goes with being able to charge from a standard alternator, which I won't be changing, the whole maintenance/repair theory behind the build of my LR130 is to keep as near standard as possible for ease of repair/replacement off grid/remote locations etc.. etc... becomes an expensive "like to have".
2. Rebuilding my (almost new) auxiliary lithium set up to be able to cope with hard winching - becomes an expensive remodel.
3. If I do find myself needing a long hard winch to get me out of a situation, it should be "once in a blue moon", AND I'll just have to put up with it taking a while using a single !!!
Plus, I don't have a huge amount of space for a bigger battery bank re-build.
 

llamalander

Well-known member
I've always counted on running my truck when using the winch, so the starter battery need not power it alone. I'd try that out on your rig first before you go spend any money. The Gods Must Be Crazy movie has a good example of a winch test--
 

nickburt

Observer
I've always counted on running my truck when using the winch, so the starter battery need not power it alone. I'd try that out on your rig first before you go spend any money. The Gods Must Be Crazy movie has a good example of a winch test--
Yes, I always do too.
 

alia176

Explorer
I have a Warn M10k winch and I purposely buried my 7500# 80 series landcruiser for a winch training class many, many moons ago. It was Midwest mud, nice and black! IIRC, the current showed was 600amp+ while operating the winch. These current loads are sudden and came as multiple hits which probably wouldn't be appreciated by fancy batteries. This vehicle has two LA batts under the hood, connected by a dumb solenoid.

I'm still running LA batts on all of my rigs and the camper, and haven't jumped on the new tech batteries.
 
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alia176

Explorer
Modern day alternators can handle pumping out high enough voltages to keep AGM batts happy. Sometimes a simple trick to full the alternator into pushing out higher voltage is all it takes. My '96 landcruiser alternator would destroy AGM batt over a year. Hopefully, your charging system can output the required voltage for the batteries you're going to be using.
 

TwinStick

Explorer
We had a 2008 Dodge Power Wagon. It had a winch and a 160 amp alternator & 1150 cca battery and it was unbelievably inadequate for running the winch. The charging system light would start flashing after 10 seconds of light duty winch work.

Only thing that solved it was a 370 amp alternator and some 2/0 high strand welding cable and a 1150 cca auxiliary battery.

The 220 amp alternator on our 23'ZR2 also has to run a 600 watt electric water pump. So we are not getting the full 220 amps as the water pump always has to run.

A 12,000 lb Warn winch can draw 400-600 amps at full load. Let that sink in for a minute..........that's a LOT of amps. Don't skimp on wire or gauge. That amount of amps can heat up and melt wire very quickly and cause a fire if not big enough.
 

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