High Output Alternators?

[jzak]

Hey guys,

Seems like everybody with a jeep has a 100+ Amp Alternator. Is it really worth dropping hundreds on a high output alternator? The only thing i'm running that isn't factory electronics is my two 55w HID off road lights, and my 9500 lbs Smittybilt Winch. Do I need a AMC 150 amp alternator for that? Would a 60-70 amp alternator be good enough?

Thanks!

 

[BusaDave9]

High output alternators are needed only when you add a lot of electrical components to your jeep. The winch is the only thing I'd be worried about. A winch can draw more amps than any alternator can put out. A 2nd battery is the best solution. Then you could keep the OEM alternator. Otherwise you could winch then let the engine run to charge the batter back up before you winch some more. If you just winch, winch winch you can run your battery dead. If the engine dies you are really in trouble.
It' all depends on how much winching you plan on doing. A stock alternator can deal with the lights and stereo.

 

[jzak]

Thanks for the feedback! I'm maybe using the winch a few times a year, and around a minute pull duration. I typically don't go on trails where your constantly needing to get winched out. That being the case, should I be worried about my stock alternator?

Thanks!

 

[hole]

Replacing alternator - Should I go for the 140 AMP model? - JeepForum.com. jzak This thread should help you a bit. About 5-6 posts down you will start to find responses from Jeephammer, sharp guy with more info about alt's and electrical than most of us ever wanted to know. Personally I went the overkill route with a CS144 which requires you to modify the mounting bracket, a CS130 bolts right in. On this site Jeephammer goes by Teamrush and you can also read more of his stuff at Junkyard genius as well

 

[Lumpy Grits]

I have a 65 amp alt on my Jeep and also a Warn Winch(8274).
Never felt the need for larger alternator.
I have a 'hand-throttle' that I set to about 1500 rpm when I'm run'n the winch.
I also run an Optima 'red-top' battery with 4/0 arc-welding cables to the winch, starter and GND.
In the 30+ yrs I have owned my Jeep. This set up has work very well.

LG

 

[IOPort51]

I have a 140 Amp alt. Don't regret it but can't recommend it. I knew it mostly bling when I put it on. I do think the 65 amp was a bit lite Do keep in mind that the larger alternators work best with serpentine belts. V belts will chirp a bit when they have a load of any consequence at all. Looking back I think that if the alternator ever failed with the 65 Amp I would be looking for something in the 90 to 100 range.

 

[jzak]

Thanks for the reality check guys. I think Jeep owners tend to over engineer their rigs. While I don't want to kill my battery, i'm also not planning on crossing the Darién Gap and time soon.

It sounds like if I don't pull for more then a minute, keep the engine revved up during the pull, and then after using the winch, run the engine for a while to recharge the battery, I should be fine.

Thanks!

 

[Torxhead]

All great advice and I might want to add keeping an eye on the voltmeter to see just how that battery is doing.
Edit: I never get tired of reading Jeephammer's posts.

 

[Posi]

My CJ7 has a couple 100 amp alternators, but I'm running an on-board welder and air, along with fuel injection.

I swapped out my stock 63 amp 10si for a 94 amp 12si on my current build. Basically it's the same alternator with better cooling and higher amps. I'm geared at 106.1 so it will see plenty of idling on the trail were the higher output comes in handy. I found one at the bondyard for $15, from a 84 camaro. New they can be found for $70.

 

[HackFabrication]

I've got a 160 amp 3G on my Ford 5.0L:



It has a smaller pulley that spins the alternator faster at lower speeds.

 

[steve1973]

My 73 has a 37 amp alternator and was a snow plow jeep. I have also had 2 other plow jeeps and as you can imagine the continuous up and down and side to side of the plow at low RPM's is quite a draw and most likely similar to occasional winching. Usually you are plowing at night, so lights are on, fan is on and every other electronic draw. The only time the amp gauge would go negative is while using the plow at pure idle. I never felt a need to upgrade. Also your wiring may or may not be up to the high alternator output, which could lead to serious problems. My 73 wiring, with no fuse block, is not up to the task of a high output alternator.


Sent from my iPhone using Tapatalk

 

[jdcaples]

If you do upgrade, mind the wire sizing. Proper wire size is critical.

-Jon