Just went down to the junkyard and grabbed an alt from a P38 for $40! It looks aftermarket, since it doesn't have any of the LR markings on the plastic cover. Should I keep an alternator in the truck as an emergency-kit thing? Or is that overkill.

 

I have had from time to time use my winch to haul out stuck myself or Rovers on our trips (perhaps 2 to 4 times per year with 10 min to 15 average run times). I heard upgraded 200 to 250 amp alternators would be ideal for the heavy amp draw of the winches. Is it overkill?

 

Had one moment of fear when I turned everything on at idle to test the alternator

high beams
driving lights (after market)
heated seats
heater fan on max
windshield heater and Defrost
VHF radio transmitting on Med power

I had a brief drop to 11.6 volts maybe 20 seconds then charging voltage returned to normal after a brief belt squeal. Re did the test after a short drive and the issue has not returned.
Charging voltage starts a 14.1 dropping to 13.6-8 after about 20 minutes so normal.

This alternator has been in a bucket for 3 years as a spare so no complaints.

New Alt on the way.
Battery appears to have survived the experience

 

acg I would be concerned that the wires aren’t big enough to handle 250A. Maybe need to add a cable directly from the alternator to the high draw appliance? I also suspect the reason we get away with smaller alternators for our winches is that we typically use winches at idle rpm where the alternator isn’t putting out it’s maximum current anyway.

 

Just bought this one last week, seems to be working fine For now that is. My battery is from 2016 (long story) but i'll be getting a new one this coming week. The alternator pumps out 14.2v for the most part, dips down randomly to 13.5 but I'm thinking its the battery going south.

 

@Saturnine I would think that a dipping voltage is a sign that the charging regulator works.

 

I bought a Britpart alternator from Lucky8 and it works just fine.