Solenoid or Relay for Winch?

jsmoriss

Explorer
After a recent encounter with a tree, I'm having second thoughts about my winch wiring. I generally use relays and fuses on everything, but my winch is directly connected to the battery. This can be an advantage for reliability, but in case of an accident, can also cause a nasty short. :) Is anyone using somekind of solenoid or relay on their winch? Fused? Sealed?

Thanks,
js.
 

cruiseroutfit

Supporting Sponsor: Cruiser Outfitters
What model of winch?

95% of winches out there already utilize either a 2 or 4 solenoid setup, I can't really see a reason to add another?
 

jsmoriss

Explorer
cruiseroutfit said:
What model of winch?

95% of winches out there already utilize either a 2 or 4 solenoid setup, I can't really see a reason to add another?

Warn 9.5si.

Right now the winch is always "ON". I'm thinking a safer approach would be add a switch with a self-latching solenoid or some-such. The max rating of the winch is 400A, although I expect the #2 wire wouldn't last long with that load. That way, in case of a crash / short / etc. the winch circuit might not be live...

Just a simple 400A fuse might also be another idea...

js.
 

DaveInDenver

Middle Income Semi-Redneck
I think what he's asking Kurt is about a way to disconnect or fuse the heavy cable from the battery to the control box, right? I'd consider a switch at the battery, similar to this. Imagine the section where the quick connector is being the wiring to your controller and harness. I agree, I would never leave any significant length of wire or cable exposed without some protection. In the case of a winch, though, putting in a fuse wouldn't be ideal (mostly it would be expensive and kind of a PITA). A length of fusible link would work, but an isolation switch at the battery was my plan for whenever I get a winch.

wiring.gif
 
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cruiseroutfit

Supporting Sponsor: Cruiser Outfitters
jsmoriss said:
Warn 9.5si.

Right now the winch is always "ON". I'm thinking a safer approach would be add a switch with a self-latching solenoid or some-such. The max rating of the winch is 400A, although I expect the #2 wire wouldn't last long with that load. That way, in case of a crash / short / etc. the winch circuit might not be live...

Just a simple 400A fuse might also be another idea...

js.

Makes sense I supposed. I would be less worried about the winch causing the short as much as the length of cable from the winch to the battery. In that case you may just want to install a heavy duty connector between the battery and the winch, gives you a quick way to disconnect things or even leave it disconnected when not in use. The numbers are a bit deceiving when you really think about it. Sure it can theoretically pull a momentary 400A load, so you would need your fuse or relay to be up to 400A, however even if the two cables were to potentially short, it might melt them before blowing a 400A fuse, not sure?
 

DaveInDenver

Middle Income Semi-Redneck
cruiseroutfit said:
Makes sense I supposed. I would be less worried about the winch causing the short as much as the length of cable from the winch to the battery. In that case you may just want to install a heavy duty connector between the battery and the winch, gives you a quick way to disconnect things or even leave it disconnected when not in use. The numbers are a bit deceiving when you really think about it. Sure it can theoretically pull a momentary 400A load, so you would need your fuse or relay to be up to 400A, however even if the two cables were to potentially short, it might melt them before blowing a 400A fuse, not sure?
Depends on time, but yeah, a 2 AWG cable will probably melt at 400A continuous for long times. It would be rated to carry about 100A depending on insulation and temp. I'd probably protect a 2AWG cable at around 400A with regular fuses or breakers, maybe lower with a slow blow. I don't have my NEC book here, but that seems about right for 2AWG copper. The problem would be nuisance trips and that would happen at inopportune times. You wouldn't want a fuse opening mid pull.
 
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jsmoriss

Explorer
DaveInDenver said:
an isolation switch at the battery was my plan for whenever I get a winch.

Generally you'd want to fuse / switch power closest to the battery. With a switch like you pictured, you'd have to open the hood and pull the switch to kill the circuit. I think a fuse, breaker, solenoid or relay would be a better idea. The trick is to find something that can take 400A for a short while, doesn't use power itself (for example, a self-latching solenoid), is somewhat sealed, and is reliable. As DaveInDenver said, it would suck to blow a fuse mid-pull. Then again, to blow a 400A fuse, you'd probably have to stall the winch for several mins... So blowing the fuse might save the winch. :) Using a fuse, I would expect most people to carry one or two spares anyway. :)

js.
 

DaveInDenver

Middle Income Semi-Redneck
I'd be a little surprised if a stalled winch motor would draw 400A, but maybe. A fuse is gonna blow quickly, within a few seconds of the overload condition, but that depends on the fuse type and actual current and temp. As long as the winch is turning, I would doubt a 400A fuse is going to blow. It would be most likely to open when you first start or stall, if normal operation would even cause it. I think a fuse is a possible solution, although I'd probably be thinking more along the lines of a fusible link for a 12VDC circuit. But in any case, my guess would be that you are concerned about short circuit only.

FWIW, my thinking on a switch was to close the switch while on the trail, but driving around to work and stuff, have the whole winch circuit unpowered. That way an accident doesn't involve leading nose first with a live circuit fed through a 2AWG cable. I would avoid a latching solenoid that would require power to unlatch. Many race sanctioning bodies require a switch or battery disconnect for this reason, a positive way to kill the electrical system in a wreck.
 

HenryJ

Expedition Leader
I have been using a waterproof resetable 150 amp breaker for my wiring connection to the battery. I soldered a copper lug into a battery terminal and attached that to the circuit breaker.

150breaker.jpg


I use a Milemarker 9000# winch. My winch is on a cradle and mounted to the receiver hitches on the front or rear of my truck.

HID2.jpg


The electrical connections are quick connects that also allow me to attach booster cables as needed:

boosterc.jpg


While not in use I can use the circuit breaker to de-energize the cables to the front and rear. I like this safety feature.

My winch is capable of drawing as much as 300 amps. There is no way my system would handle that load. My alternator is capable of up to 200 amps. The stock vehicle systems need 50 amps. That leaves me 150 amps on a good day. That was my rational when sizing the circuit breaker. Flawed? Perhaps.
If I find the breaker is woefully undersized I can by pass it by bolting the cable directly to the battery. This can be done in the field. A good plan should the breaker fail. Originally I did use a 100 amp breaker. It failed due to water intrusion. That is why I installed a waterproof breaker this time.
I have not exceeded the capacity of either breaker to date. I have not been in a worst case pull either. I tend to err to the side of caution. I would probably add a pulley and take more time rather than to over heat my winch.

I just offer this as the way I did mine. It works for me and may give you some ideas.
 

Antichrist

Expedition Leader
jsmoriss said:
Is anyone using somekind of solenoid or relay on their winch? Fused? Sealed?
For all intents and purposes, in an application like this a solenoid and relay are the same thing.
The easiest solution would probably be a battery disconnect switch that's normally turned off. Unfortunately most you see are woefully under rated for a winch application.
I'm using a Cole Hersee battery disconnect, PN 75908. Rated at 2000amp intermittent, and 300amp continuous, it can handle 500amp for several minutes.
 

DaveInDenver

Middle Income Semi-Redneck
Antichrist said:
I'm using a Cole Hersee battery disconnect, PN 75908. Rated at 2000amp intermittent, and 300amp continuous, it can handle 500amp for several minutes.
What is the duty cycle at 500A? I read the specs for Cole Hersee #75908 as:
300A continuous
2000A intermittent for 30 sec on/3 min off
 

Antichrist

Expedition Leader
DaveInDenver said:
What is the duty cycle at 500A? I read the specs for Cole Hersee #75908 as:
300A continuous
2000A intermittent for 30 sec on/3 min off
I don't have the chart here at work, but they sent me a graph showing how the duty cycle declines as the amperage goes up. At 500amp it was several minutes. Not like 10 minutes, but time enough to turn it off. If you leave it normally off you'd really only need to use the high amperage if your solenoids stick closed. I haven't seen any rated nearly as high, for the price these are, which is under $40US. You could get compulsive and install two in parallel.
Cole Hersee makes quality vehicle electrical equipment, but if anyone knows of something as good for a comparable price, I'm all ears, or eyes, as the case may be. :)
 

madizell

Explorer
How much amperage your winch will draw under a given load is determinable from charts published by all the major winch manufacturers. If Warn (for example) says their winch will draw 450 amps at a given load, I would expect that it will. How much amperage is available from the alternator is not directly relevant to what the winch will consume or what the wiring has to handle because the alternator is not (directly) supplying the power that the winch is consuming.

Your battery is the primary source of power for the winch, and generally the battery is capable of providing amperage in excess of 800 amps for long enough to melt most any wiring if a dead short occurs. The battery itself can melt or catch fire if shorted. So, inserting breakers or fuses in the 150 amp range into a winch harness would defeat the usefulness of the winch, even if it would provide some degree of protection against damage or fire resulting from shorts. If a good battery can (and should) provide pulse amperage in the 1,100 amp range, what kind of a circuit interrupter would you use to protect the system?

In my opinion, the winch manufacturers tell you to wire the winch directly to the battery for a reason. The wire harness provided is the only wiring on the vehicle capable of sustaining the amperage load the winch demands under its rated range of performance. Degrading or limiting the harness rating would only degrade the performance of the winch.

Many winches will, in fact, consume 400 amps or more even when not stalled. A full stall electric motor consumes a lot of amperage, and it may well spike under those conditions to amperages well above those shown for the same motor under a running load. Having never had a load meter on a stalled winch, I don't know what the amperage consumption could spike to, but I would assume it would be well above the maximum draw shown for the winch under load. Still, I have stalled my winch many times without damage, and without causing a fire, so whatever the draw was, the system was able to provide it and sustain it at least briefly without negative result.

Most of the time when using a winch for recovery, you will not pull maximum loads and thus will not pull maximum amperage. We routinely use only 2,000 to 4,000 pounds of pull for recovery, even with rigs far heavier than that and with winches rated for 8,000 to 12,000 pounds of pull. Check the power consumption chart for your winch. Instead of focusing on the maximum ratings and loads, look at the consumption for a 2,000 pound pull on the first wrap or second wrap and you will find that the power consumed is far less than maximum, and probably within the range of a heavy duty alternator. If this was all the winch ever was asked to do, a 200A breaker would probably do fine in circuit.

However, the power harness for the winch should be built to handle the maximum load anticipated, not the nominal load or average demands of recovery. You simply can not control the amount of power needed by your winch when recovering a vehicle, so you need to build for maximum effort.

I would not recommend using a circuit breaker or fuse in a winch harness for the simple reason that it is both possible and likely that you will see momentary power consumption far above the rating of any such device if the breaker rating is lower than the winch demands. I don't see a point in this, because you will be resetting breakers or replacing fuses when it really is not required otherwise.

Having used winches on vehicles in extreme circumstances now for a lot of years, I can say from experience that I have never seen a short in a winch harness. I have even used mine repeatedly while the winch was fully submerged, without issues or shorting. If the harness is correctly routed, not subjected to abuse or excesses of heat and abrasion, or neglected, the likelihood of a short is so far down the probability scale as to be not worth taking extraordinary steps such as installing circuit interrupters.

My recommendation is to install the winch according to manufacturer's directions and let it go at that.
 

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