Topic: Dead Alternator

[GTChrisB]

Here's the problem.  My wife bought me a 10k winch and new bumper for my birthday.  I recently replaced the alternator with a new stock model, new battery the same day.  Everything bolted up fine and worked, but had a squeal on the belt.  Replaced that, tested everything out and it worked fine.

Started the Jeep tonight to make a quick run to the store and the belt began screaming like a banshee.  No power other than the battery on the meter, pull back in and the alternator is frozen solid.  Can't even manually turn the pulleys by tugging on the belt.  It worked perfectly the day before just to show the wife how everything worked, and I didn't even start the motor...just a 5 ft spool out of the cable, no load.  (She had been out of town and wanted to see it work). 

Since the alternator is under warranty, it'll be no problem to replace it tomorrow, just will hold off on anything that will be hard on it.  Question is, should I get a dual battery kit or a bigger alternator.  Both would be nice and is planned for the future, but I need something that will be reliable until then with winching only when I need to use it. 

[TrailsLessTaken]

I would do a bigger alternator because even if you add a second battery then its draining both batteries down and the alternator will have to work that much harder to keep the two of them charged. If your doing a short pull then the double battery might be fine but if you get in to where you're using more juice then the alt. is putting out eventually you will drain both batteries.   Check the FAQ that has a list of hi amp alternatorsin it that will bolt on, also make sure to upgrade the wire that goes from the alt. to the battery to a larger gague also if you do a bigger alt

[aw12345]

Awhile ago we did some trail repair work and part of that was pulling a big fallen tree up a hill took 3 winches, Mine with the stock battery and al;ternator kept up just fine as long as I kept the engine reved up to atleast 3 grand and we pulled on this thing for close to half an hour as long as I reved the engine the valtage would stay at a reasonable level. The only thing overworked was the poor winch that thing was plenty hot

[FourbangerYJ]

I would go with a bigger alt. VS. the duel battery setup. The dual batteries are heavy for one. And you would need a new battery tray and the management system for the batteries which is spendy. Plus it sounds like your alt. took a dump and you need a new one anyway.

[Jeffy]

I agree with the bigger alt.  That's what I run.  My battery is an Optima 800U though.  Really, it will depend on what the Jeep is since TJ's usually come with larger alternators then YJ's.

I bought my 170A for around $100.  It was a custom rebuild with a 3 year warranty.  I have no complaints and it's worked great.

[GTChrisB]

Strange thing, I was getting ready to take the alternator out and started the engine...worked perfectly.  Drove around for about 10 minutes and parked it.  Later this evening, started it and the thing froze again.   

It'll be a little while before I can get a bigger alt (headed to Army BCT next month), but at least I can put a stock one in there so my wife can have a third vehicle while I'm gone.  Thanks for all the replies.   

[Jeffy]

I'd take it out or at least take the belt off and turn it by hand.  The only reason it should lock-up is if there is something floating around in the case.

[sjwrangler]

Hopefully this is not a dumb question. With the 2.5 being limited in power, does a larger alternator affect the overall performance of the Jeep? Does anyone notice any difference?

[Jeffy]

Hopefully this is not a dumb question. With the 2.5 being limited in power, does a larger alternator affect the overall performance of the Jeep? Does anyone notice any difference?

No.  When it's running at lower speeds, it makes more power then your OEM does with the same amount of resistance.

[jaywiz1977]

You definatly have something broke loose in that alternator as jeffy said that is the only way a alt wil seize then let go and seize again.Take it back and have them replace it.as far as the alt size is concerned,try dropping the pulley size on the alternator,what this does is makes it spin faster at idle and produce more charge(most alternators don't start producing much of a charge till around 1500 rpms)that why the guy pulling the tree had to rev to keep up.pulleys are alot cheaper than high amp alternators,and help out a ton.We do this quite often at work when we install a monster stereo system for someone and they cheap out when it's time to go high amp alternator,so it's a pulley and a optima yellow top.the yellow top will help out a ton as well,they have huge reserve for high draw applications.Also you SHOULD upgrade the wire that goes from you alt to your batt as well as the ground wire from your battery to the motor,this often helps due to the alternator not having to try to cram all that amperage through that little wire hat comes from the factory.

[jcsanders79]

I'd put the replacement alternator back in and get a yellow top Optima.  I've got one and it works fine with the winch and the Jeep not even running.