2001 Explorer Sport Battery Dying

[AM]

Hey Guys, new here. Never been a member of an automotive forum, and not an expert by any stretch of my imagination. But, I'm hoping you guys can help.

The battery on my 2001 Explorer Sport keeps dying. There are no interior lights or headlights left on, so I can't figure out what the problem is.

I boosted it yesterday afternoon to get it going, took it for a 10 minute drive (it idled outside the coffee shop for 5 of those 10 minutes) went home, and turned it off. It wouldn't start again without a boost. So, I boosted it again, took it for a 15-20 minute drive to Home Depot, and all was OK. I used the highway to run her through her paces a little. I came out of Home Depot about 20 minutes later, and it started right back up as if nothing was wrong. I went home, parked it, and when I went to leave this morning it was dead again.

- There are no interior or headlights on.
- Mind you, the reading lamp bulbs are both blown in the front overhead
console. If the lamps were switched on with blown bulbs - would this
drain the battery?

- The battery is only about a year and a half to two years old.
- It does have an anti-theft system, but I would hear the horn/see the lights
if it had been activated.
- There's about 278000 kms on it.
- There has never been a single mechanical problem at all... Until this.

I don't want to take it to a shop and get bent over the table. Any suggestions on what to check?

I just want my girl going again.

 

[Mike Deege]

Sounds like the alternator, test the battery first. Also check the terminal cables. Always start with the least expensive items first. Also get a good, by recommendation, mechanic. Times are touph, alot of mechanics want steady customers, so if you go in with some knowledge, you won't get burned. And you'll have a mechanic you can go to. A tip would'nt hurt either, I'm a bartender, I tip everybody, and you would'nt believe the dividends it pays. Good luck, Deege

 

[gijoecam]

If it was the alternator, it would not continue to run when the battery went dead. Odds are it's the battery not holding a charge. A quick check of the voltage with a multimeter when it won't start will confirm the problem.

-Joe

 

[C5Mike]

It would be reasonable to presume that the problem is being caused by either the battery or the alternator.

I would start with the battery by disconnecting the battery cables and charging it overnight at a 2 amp rate with a battery charger you know to be good. After it has charged for 12 hours or so connect a battery load tester (about $70 at O'Reilly Auto Parts). This will show how many amps the battery will put out at what voltage. If the battery tests good, reconnect the battery cables and move to the alternator. If you don't have a charger and tester and don't want to buy them you could take the battery to a battery store and ask them to charge and test it for you.

A failed diode in an alternator can quickly discharge a battery. An easy way to test for failed alternator diodes is to start the engine and connect an oscilloscope across the battery terminals and observe the waveform. If the diodes are all good the trace will be a straight line. A bad diode will cause blips on the trace that will be obvious. It is easy to see if an alternator is charging or not by watching a voltmeter. With the engine off it will read about 12 volts. With the engine running the voltage should read about 14 volts.

If the battery tests good and you don't have access to an o'scope and multimeter, you could throw a new alternator at it and see if that fixes the problem.

Michael

 

[XLT]

I would first try charging your battery fully. Sounds like you keep boosting (jump starting?) your battery then run it for 20 minutes which is far from sufficient for getting that battery back up in running shape. Or take the battery in to get it load tested. The other members have provided some very good info as well.

 

[Macgiobuin]

Take the blown bulbs out and check them for continuity with an ohmmeter. The tungsten coil in the element evaporates onto the glass giving it a mirror finish from the inside, and can cause a short circuit within the bulb and appear to be off, when it has actually been turned into a glass heater. Nonetheless, ditch the bulbs after you do the test and replace them. If the replacements stay on, you probably have a stuck relay.