How many amps would a VSR need to handle for winching?

[AussieAnth]

Haven't been able to find a difinitive answer to this question.

I've got a Runva 11XP winch, factory starter battery, and a 100AH battery in a quality battery box back the canopy, wired directly to the starter battery, using very heavy guage wiring. The battery box has an isolator, but I think its only rated to about 70amps. Im going to remove the isolator from the box & install an upgraded Voltage Sensitive Relay (VSR) unit in the engine bay, primarily so I can also draw on the 2nd battery when winching.

The following table below is from the Runva website.

Does this mean I need a VSR that can handle up to 430amps if I want the 2nd battery to assist the winch at maximum pull? Or is there some forumla that says 200amps or something will be enough?

Based on the assumption I'll need up to 430amps, Im looking at the Blue Sea ML-ACR (good for 500amps) with manual override. Any other VSR suggestions? If 140amps is enough, I'l probably get the Matson MA98404 (140amp max) with manual switch.

12v dc
Current draw Line Pull
Amps (max) Lbs

100 0
220 4000
330 8000
430 11000

[NowForThe5th]

Is your second battery deep cycle? If so then you really shouldn't be using it for the winch. If you want more power for the winch then a bigger starting battery would be a better choice. That being the case, there should be no need for a VSR capable of powering a small city.

And when do you think you'll be using the 430amp, 11,000lb capacity of the winch? Wringing wet, your Triton shouldn't weigh more than 3000kg which is 6600lb and that's only going to pull less than 300amps straight up the side of a cliff. In reality, you're probably never going to be putting a load of more than 4000lb on that winch.

Interesting theoretical, though.

[ag9111]

and not all the current will be drawn from the 2nd battery. They will share the load but not 50:50. Ratio will depend on type of battery, age, charge state, temperature and a host of other things

As noted above. Deep cycle are not good at delivering large currents for extended periods of time. It will reduce their service life as well

[4wd26]

Is your second battery deep cycle? If so then you really shouldn't be using it for the winch. If you want more power for the winch then a bigger starting battery would be a better choice. That being the case, there should be no need for a VSR capable of powering a small city.

And when do you think you'll be using the 430amp, 11,000lb capacity of the winch? Wringing wet, your Triton shouldn't weigh more than 3000kg which is 6600lb and that's only going to pull less than 300amps straight up the side of a cliff. In reality, you're probably never going to be putting a load of more than 4000lb on that winch.

Interesting theoretical, though.

I disagree with the bit in red.

many times, depending on the situation you can have up to 3x the vehicle weight on the winch
in mud with suction is the worst, and then add in a gradient.

I went in search of a guide I once seen (warn winch winching guide- advanced version I think) which covers some scenarios and provided table, or multipliers for anticipated winch load.

can quickly get beyond the capabilities of the winch- single line pull= max amps

[AussieAnth]

Is your second battery deep cycle? If so then you really shouldn't be using it for the winch. If you want more power for the winch then a bigger starting battery would be a better choice. That being the case, there should be no need for a VSR capable of powering a small city.

And when do you think you'll be using the 430amp, 11,000lb capacity of the winch? Wringing wet, your Triton shouldn't weigh more than 3000kg which is 6600lb and that's only going to pull less than 300amps straight up the side of a cliff. In reality, you're probably never going to be putting a load of more than 4000lb on that winch.

Interesting theoretical, though.

Thanks Chris. Yes the 2nd battery is a deep cycle. I dont go chasing recoveries, so winching is only an occasional requirement.

So it sounds like, if I want the 2nd battery to provide a bit of backup power, 140amp or 200amp would be suffient?

Thanks everyone for chipping in. Much appreciated.

[NowForThe5th]

We're not quite finished yet....

The basic formula for calculating winch load is:
Weight of vehicle/60*Gradient in degrees

To that must be added a factor for resistance of the surface
Bitumen road +3%
Grass +15%
Sand +20%
Mud +30%
Bogged +50%

So,

Winching a 3000kg vehicle up a 30 degree slope on a hard surface will require

3000/60*30*1.03 = 1545kg

The same vehicle, same slope but in mud will require:

3000/60*30*1.30 = 1950kg

There are factors to add for things like flat tyres and angle of the winch and you can reduce the necessary force by using pulleys.

So, the actual force required isn't quite what you think it might be.

[AnOldFart]

Haven't been able to find a difinitive answer to this question.
I've got a Runva 11XP winch, factory starter battery, and a 100AH battery in a quality battery box back the canopy, wired directly to the starter battery, using very heavy guage wiring. The battery box has an isolator, but I think its only rated to about 70amps. Im going to remove the isolator from the box & install an upgraded Voltage Sensitive Relay (VSR) unit in the engine bay, primarily so I can also draw on the 2nd battery when winching.
The following table below is from the Runva website.
Does this mean I need a VSR that can handle up to 430amps if I want the 2nd battery to assist the winch at maximum pull? Or is there some forumla that says 200amps or something will be enough?
Based on the assumption I'll need up to 430amps, Im looking at the Blue Sea ML-ACR (good for 500amps) with manual override. Any other VSR suggestions? If 140amps is enough, I'l probably get the Matson MA98404 (140amp max) with manual switch.
12v dc
Current draw Line Pull
Amps (max) Lbs
100 0
220 4000
330 8000
430 11000

A --lateral-- and probably considerably less expensive thought .....
If we momentarily put aside the expressed concerns about the -wisdom- of using your 100AH secondary battery for this job and just look at the "mechanics" involved then why not simply -bypass- your present 70 Amp rated battery box isolator, -when required- ie, when winching, by installing one of -these- across it, that are rated to 500 Amps "Peak" load capacity.
http://www.aliexpress.com/item/New-500A ... 48360.html
or, possibly even simpler and more reliable, one of these, which, if you simply combined both 200 Amp rated "blades" together, will give you 400 Amps "Continuous" load capacity.
http://www.aliexpress.com/item/Double-P ... 30865.html
....

[FredSmith]

Being a crane operator, I know if you put a pully block and hook the hook back to vehicle, close by tree etc, you double your pull, therefore halving the load/current draw on the system.

HTH

[Kegsy]

Plan for the worst...
Setup for the MAX amp draw on the winch to be safe. You don't want hot / melted wiring and components leaving you stranded or worse on fire

[Sootie]

Is your second battery deep cycle? If so then you really shouldn't be using it for the winch. If you want more power for the winch then a bigger starting battery would be a better choice. That being the case, there should be no need for a VSR capable of powering a small city.

And when do you think you'll be using the 430amp, 11,000lb capacity of the winch? Wringing wet, your Triton shouldn't weigh more than 3000kg which is 6600lb and that's only going to pull less than 300amps straight up the side of a cliff. In reality, you're probably never going to be putting a load of more than 4000lb on that winch.

Interesting theoretical, though.

Thanks Chris. Yes the 2nd battery is a deep cycle. I dont go chasing recoveries, so winching is only an occasional requirement.

So it sounds like, if I want the 2nd battery to provide a bit of backup power, 140amp or 200amp would be suffient?

Thanks everyone for chipping in. Much appreciated.

Just use your starting battery mate, while the car is on the starter battery can provide the full power required. The only time you may need a second battery is if you were winching for a long time with the car off and as above deep cycle batteries are not designed for that so it will kill it.

I have the same winch and a single battery (factory mitsu) and I have pulled a jeep off a log without issue (and it was dragging the triton forward).

[fridgie]

My ironman winch pulls near 500 or 600 amps at full load, has been on the car for roughly 4yrs and I only have 1 battery. Have melted connections and smoked up the winch, used it excessively and always been able to get home. Keep your existing setup and have the dual battery able to link in to 'jumpstart' the vehicle if needed.