Battery/charging issue

[ppd1107]

So I go driving in the woods with a couple of other jeepers yesterday. I drive 20 miles or so to my buddies house. When we leave, jeep starts. We drive 15 more miles to the starting point and stop. Jeep does not start. It acts like the battery is dead, with the starter barely turning over. I get a jump start and everything is good. 7 more miles we stop. I wisely park facing down hill. Go off to do some sight seeing. Return, and the jeep won't start. Roll start it down hill and it runs. As I am driving along and it is Oregon, I have the wipers going and the defroster going. These slow down so I turn them off. At our next stop I have one of my buddies hook the jumper cables up and leave them hooked up for a few minutes. Jeep starts and off we go. Drive another 45 minutes then stop. This time the jeep starts on it's own. We drive and stop after an hour or so and eat lunch. After word the jeep starts on it's own and the wipers seem to moving the correct speed. At first I thought my battery or alternator was bad. I have never heard of a battery, stop being bad. Does an alternator stop working then start though? Any ideas are welcome.

 

[Cheepjeep85]

i'd take em both and have em load tested, simple and free at your local parts store.
to answer ? you were probably building the batt up from jumping it off, to run it a little while, it doesn't take much to run the ignition for a short period of time. should also clean all of your connections with a wire brush, and use a good terminal protectant on your batt post. corrosion can make it do some funky stuff.

 

[fzsk4p]

So I go driving in the woods with a couple of other jeepers yesterday. I drive 20 miles or so to my buddies house. When we leave, jeep starts. We drive 15 more miles to the starting point and stop. Jeep does not start. It acts like the battery is dead, with the starter barely turning over. I get a jump start and everything is good. 7 more miles we stop. I wisely park facing down hill. Go off to do some sight seeing. Return, and the jeep won't start. Roll start it down hill and it runs. As I am driving along and it is Oregon, I have the wipers going and the defroster going. These slow down so I turn them off. At our next stop I have one of my buddies hook the jumper cables up and leave them hooked up for a few minutes. Jeep starts and off we go. Drive another 45 minutes then stop. This time the jeep starts on it's own. We drive and stop after an hour or so and eat lunch. After word the jeep starts on it's own and the wipers seem to moving the correct speed. At first I thought my battery or alternator was bad. I have never heard of a battery, stop being bad. Does an alternator stop working then start though? Any ideas are welcome.

Yes and no. Heat can play a factor with the voltage regulator.. So can all the slow speed running in the woods. Slow speed = low/no charging.

Do the simple cheap stuff first.

Belt tight ? Not slipping ?

How about the cables ? The connections must be clean at both ends of the cables. Inside and out. Don`t forget the battery terminals also. Corrosion can wick down under the insulation and corrode the cables internally too. A cheap but wise investment would be to replace the cables if they are of any significant age. If you go that route. Bumping from say a 4 gauge to a 2 gauge is a wise move. More copper and less resistance.

It would be a good idea to check your ground connections in the harnesses. If it even looks suspicious, then clean and/or replace the connection.

If all the above checks out. Then take the alternator and have it tested.

Rather then a auto parts store. Look for a alternator rebuild shop. Or automotive electrical shop. They can often rebuild your alternator with new bearings/brushes. Lot`s cheaper and you end up with a better unit then the POS auto parts rebuilt junk.

 

[elwood blues]

^^^ What he said