Just a couple of points about winches, perhaps especially applicable to heavier vehicles:

1) Don't get too hung up on the "problem" of a winch not working when the engine isn't running. The only situation where that is even vaguely an issue, is the "stuck-in-a-raging-torrent" scenario. And in that situation, the advantage of an engine-free electric winch is in any case dubious at best (assuming you decided to drive into water deep enough to drown your engine, without another vehicle to assist). I wouldn't like to rely on a (probably submerged) electric winch, drawing 400A or more, to pull my vehicle clear without drive-assist and without an alternator feeding it.

2) A relatively low capacity winch is ok, if you carry good rigging equipment. With 3 heavy-duty snatch blocks and a heavy-duty extension rope, you can get (nominally) 6 times the winch's rated line pull. It's slower than using a higher powered winch, but just as effective, and perhaps more versatile. (Just remember that if you "daisy-chain" the snatch-blocks, then the blocks, shackles, and ropes must be rated for the actual load, not the winch's rated load!)

3) Use (good) synthetic rope unless cost absolutely rules it out. Wire rope is more difficult and dangerous to use and rig.

4) The strength of the rigging hardware (shackles, mountings, and blocks) is more important than the strength of the rope (unless it is steel cable). A synthetic winch rope breaking is pretty harmless, whereas a broken towing eye being catapulted through the windscreen is a diffrent matter.

5) Don't be tempted to use a winch on its own as a lifting device. That includes pulling a load (your vehicle, for example) up an incline, unless the brakes can hold it in the event of a failure. Or unless you have a secondary way of securing it if something breaks, such as a secondary rope, mounting point, and anchor. ("Tail" the secondary rope in as the primary rope is pulled in by the winch. If the primary rope/winch/anchor/mounting breaks, the secondary rope system will take up the strain, and prevent the vehicle tumbling down the slope).

6) In an expedition or professional context (as opposed to recreational off-roading), needing a winch is likely to involve a long period of fairly continuous use. This is really when engine-driven winches - mechanical or hydraulic - come into their own. Electric winches are fine for quick-and-convenient assistance, but they quickly show their weaknesses when they are called upon to do several hours work at a stretch. Generally unsuitable for heavy vehicles, but ideal for ATVs...

7) The maximum line-pull of PTO and hydraulic winches is usually well regulated by shear pins and relief valves. But beware of electric winches which exert peak strains on the rope at stall. Not only can they burn out themselves and parts of the electrical system, but they can put a dangerously high shock load on all your rigging. Stop and re-rig the winch if you hear it getting close to stall!

My comments above are not about electric vs mechanical/hydraulic winches in general - only about their relative suitability for expedition use, especially for heavier trucks.

Rgds,

Michael...

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Michael & Sandy
http://www.expeditionoverland.com