Charging system

[Therou]

So this morning I head out to go to work, but first I stop off to grab a coffee. Jeep started great the first time and did so again after grabbing the coffee. About 5 mins later the check guages light comes on and the battery guage is bottomed right out. I think WTF, maybe I can make it to work and I can worry about it afterwards. Well I made it half way there. Called Pops, got a boost made it there fine, another 15kms, guage didn't drop back down at all. So after work, about 8 hrs later, I hop in and it starts up great, but the battery guage is sitting at about 12, not the usual 14. So I call ahead to let my dad know that I will probably be needing a boost half way home. True enough it dies again about halfway home, and again about 5 blocks from home.

So now I sit here with a dead jeep, and only have two days to have it back running as I work monday morning. What order should I approach things? check if the battery holds a charge? Try and find an alternator? Should I just bite the bullet and take it to a shop? Any help would be appriciated.

[Therou]

bump, please help me as i really hate to take it in.

[BCwrangler]

Do you have the original battery?You could take it to a shop, and they'll put a tester on it to check it, and the alternator for a charge. If the Jeeps dying, it sounds like a bad alternator, as it's not putting a charge in the system and draining out your battery while you drive. A battery can recharge itself partially by sitting, as long as it's not totally dead, that's probably why you can start it after eight hours.

[daveg13]

Buy an inexpensive volt meter if you don't already have one, and start checking things. You should be getting a voltage of around 13.6 with the engine running if the alternator is charging correctly. Also check/clean your battery terminals.

[Bigbob]

Originally Posted by Therou

So this morning I head out to go to work, but first I stop off to grab a coffee. Jeep started great the first time and did so again after grabbing the coffee. About 5 mins later the check guages light comes on and the battery guage is bottomed right out. I think WTF, maybe I can make it to work and I can worry about it afterwards. Well I made it half way there. Called Pops, got a boost made it there fine, another 15kms, guage didn't drop back down at all. So after work, about 8 hrs later, I hop in and it starts up great, but the battery guage is sitting at about 12, not the usual 14. So I call ahead to let my dad know that I will probably be needing a boost half way home. True enough it dies again about halfway home, and again about 5 blocks from home.

So now I sit here with a dead jeep, and only have two days to have it back running as I work monday morning. What order should I approach things? check if the battery holds a charge? Try and find an alternator? Should I just bite the bullet and take it to a shop? Any help would be appriciated.

being it is dead and needs a jump, but the gauge shows 12 volt when running I suspect a bad battery. How old is it in years and miles? I have zero battery luck and seldom get more than 1-2 years from a factory battery and 2-3 from a Die-Hard. If the alternator was bad it'd not show 12 volts at the gauge.

BTW It is somewhat normal for the gauge to read low if the battery is bad. The 12 volt reading is a dead ringer for a bad cell in the battery. But not always. You can take it to a place like autozone and they can check things out for you.

[kizer]

I'd vote dead battery if its older than 3 or 4 years old. Pull out the battery and take it to your local autoparts store. They can test it within minutes. If you need a new battery your at the right place to buy another one.

However, if the battery does take a charge it might be your alternator. If possible bring the vehicle to the parts store because most will check your battery and your alternator for free.

Both times Ive had a problem with my Jeep and my wifes Volkswagon, it was a battery that was older than 3 or 4 years and factory.

Suprisingly enough I just replaced my wifes XJ battery. Its a 98 and I just changed it 2 weeks ago. Talk about a battery that didn't want to die. It was a factory battery too. I threw in a Optima Yellow top in it as well.

[Therou]

My battery tested bad, so I got a new one, but that didn't solve my problem. So now I need to determine the next step. Voltage regulator? alternator? replace it myself or go to a shop?

[BCwrangler]

Well the battery was replaced, so it's out of way. And your not throwing any trouble codes? The voltage regulater is part of the PCM (computer) so it should be OK. The alternator isn't to bad to change, as long as your comfortable with wrenches in your hand and some patience.
You could buy a electronic manual for $20 Canadian to assist you, which might be a good idea.

[kizer]

That didn't solve your problem? Meaning it starts and still runs bad? I'd have your alternator checked.

[daveg13]

Like I said before, a $15 voltmeter would diagnose your problem very easily. Your battery probably was fine, it was just dead because your alternator isn't charging.

[Jerry Bransford]

You've likely just got a dirty/loose/corroded connector somewhere in your engine compartment. Loosen, clean, then retighten every heavy cable connector you can find. Like where the battery connects, its ground wire, where it connects to the starter motor solenoid, and the ground wire between the engine and chassis.

The regulator is inside the engine computer and not part of the alternator, plus it's reliable enough that I would not suspect the regulator in a TJ anyway. With a new battery, even if the alternator were bad, it should run so I wouldn't suspect the alternator either. Like I say, I'd be looking real hard at the main electrical cable and strap connectors inside your engine compartment!

[SomeGuysName]

You can grab a cheap voltmeter from HF for about 4 bucks. I highly recommend having one around...they are good for all kinds of troubleshooting and making sure you hook stuff up right.

[Therou]

I should clairify that it does run only it will die after about 20 kms. Made it to the gas station and back without it dieing after replacing the battery, but still have the issue of the gauge dropping down to nothing.

[Therou]

Well my connections seem to be clean and tight, I am getting the same voltage at the alternator as I am at the battery, so I am guessing that tomorrow morning I will be getting myself a new alt. and installing it. If that doesn't solve my problems I might have to give up.

[eclipse27]

Random question... Has it rained hard there previously? My jeep did this awhile ago. Battery was fine, alternator fine ect. Had to get it towed. Next day started right up. Only thing we could figure was water got on something?? ...But yea check all your connections. Also check the alnator wire to battery.