what amperage alternator is needed for a 12,000 lb winch, 4 kcs, 4 cree leds, led bar, and led bed lights

 

100+ I would imagine if you still have the boxes check the requirements

 

What kind of vehicle? A newer truck with a good battery can handle this. Seriously doubt you're going to run all this stuff at the same time. And old truck might be a different story.

 

yes i would be running them at the same time but i would turn them off when driving and when using winch i want to have them all hooked to toggle swithes
it will be on a 1991 f150

 

the KC lights is the only thing i would worry about. the current 95 amp alternator on the truck will handle the load of the LED's and winch. the winch will probably draw 25 amps or so.
the KC's if i remember correctly draw around 15 amps each, so running them would be about 2/3rds alternator capacity and put the alternator over it's limit if all the lights were on and the winch was used..
i would get rid of them and pick up a LED bar, it will use 1/4 the power of the KC's and emit a lot more light.

 

25 amps for the winch? I'm sorry, but that is just not so. A M12000 under full load is rated at 440a draw, and 49 amps no load, just spooling cable. I know some of the cheap off brand winches run well over 500a full load.

On that particular truck, while the alternator will probably be OK output wise, I would be wary of repeated high loading on the output terminals, knowing the 2g's nasty habit of catching fire. A 3g swap would be highly recommend, not known to catch fire, and even a 95a small case has a much nicer output curve, and puts out considerably more power at low rpm. I also suggest upgrading to a group 31 battery. Winch or no winch.

Personally on my wheeling rig I run a 130a 3g, a pair of 31's and it never has issues keeping up to my M12 or 8200 and 1100w of lighting. One of my buddies went as far as to add a second, isolated 95a 3g on his 95 that is dedicated to a pair of 31's for winching duty.

 

i have never had any problems with the stock alternators on any of my older trucks, and have never seen one catching on fire.
i can not say the same thing about the 3g alternators though. in the past 9 years, i have had to replace 6 of them on 4 trucks because of something shorting out and the alternator catching on fire.
the stock 95 amp alternator on my 88 has never complained about any load i put to it.
if your winch is pulling 400-500 amps, something is seriously wrong with it. my 9000 lb ramsey only draws 24 amps freewheel spool, and 75 amps at full load.
is that winch direct drive? mine is planetary gear dive.

 

First you need to add up all the equipment that runs off of that system and add approximately 25%-30% on the alternator. Might not be a bad idea to run multiple batteries also depending on how much you plan on running the winch continuously. A lot of variables to think about. A/C, stereo, other lights, cooling fans etc. A good thought out plan building will pay off in the long run.

 

No 9000lb electric winch draws only 75 amps at full load and on freewheel it's not going to draw any current at all.

For the OP.
You'll never fit an alternator that will power the winch, it's going to be getting most of it's power from the battery. The goal of a larger alternator, and you'll want as high capacity as you can fit, is to prevent the battery from going dead quite as fast and to charge it back up quicker.
That said, I used a Warn 8270 (450amp full load, but usually around 300amp load)) on one of my Land Rovers with a 40 amp generator for quite a few years, I just had to be very careful not to run the battery dead if I couldn't roll start the truck.

You don't say what winch, but any 12,000 12v electric is going to draw, depending on the load, from around 100 up to 500 amps and there will be some variation between winch brands and design.
Warn 12,000's average around 450-470 at full load. My Ramsey RE12000 draws 380 at full load but it's a worm drive and they typically draw less than planetary drive, which is the most common.

 

The only alternators I've ever had problems with are delco remy had a brand new one break one of the brushes and before that it had a habit of killing batteries occasionally to the point where they won't hold a charge anymore I switched the alternator for an idler pulley no problems for months all I did was pull the battery out twice a week and charge it got a new alternator it kills batteries every time after about 4 hours of being plugged in

 

will fenders and other different parts from a 1995 f150 go on my 1991

 

yes and no. they will bolt on, but you will have to use the complete nose. you can not just use one fender.