Battery issue..?

Right.
So, the battery is unreliable in cold weather. It tested as good at the parts shop (they hooked up a load tester) and I don't have any shorts in the main circuits. This morning, though - it damned near didn't start at all. Last winter the same issues - I had to get several jumpstarts over the season.
When I start it, the volt guage on my instrument panel drops to maybe 10 volts and then starts bounces back up. It read 13 volts after a load test at the parts shop. The cables & connections are all clean, I just replaced them all (the old cables were dead). It has never let me down in warm weather.
Should I just assume the load test was wrong and go with a new battery? Any ideas?

Who is the maker of the battery you are using?
Is it the original battery since you have purchased your Jeep?
Is there a ID tag providing Model #, and CCA ?
The battery you have might be too small in capacity and not rated for the Amp draw of the Jeep I-6 during winter weather.... When the battery is cold.... the Cold Cranking Amps of the battery is dramatically less....

The battery I use for my '98 4.0L is a 34/76 series Optima with 880 CCA.
I have upgraded my cables to 2ga fine stranded, the charging lead to 4ga fine stranded and the alternator to 136A.
Not sure what temperatures you have where you live, but when I was in Yellowstone Ntl Park a year ago... the temperature was 15* and in the morning the battery spun over slightly labored, but turned the engine over fine....

It's an Autolite 84, at least a few years old. It was in the jeep when I bought it in March of 07.

Autolite 84 appears to be a good battery manufacturer warranteed for 84 months....
What is the series number of the battery?
The battery you have installed could be too small for the needs of the 4.0L or.... the starter may be pulling too many amps trying to start the engine would could indicate the starter is having issues....

Hmm... time to pull out the voltmeter.
I'll report back.

If it's failing when cold, it's on its way out. That was how we used to test batteries back home - put them in the freezer for a couple of hours (sometime before first frost) and try to start the vehicle right after you pull it out - if it won't start, buy a new one.

H'ohkay, so...
Put in series with either the positive or negative cable (battery-voltmeter-cable) I'm getting 2.43 amps of draw. Assuming I'm doing this right, thats a lot.
Kept the DVM & pulled each relay & fuse one at a time from the power distribution center. No differences.
All I can think of is that the alternator has developed an internal short circuit - or I need to check the fuses by the passenger's kick panel.
Any ideas?

5-90 said:

If it's failing when cold, it's on its way out. That was how we used to test batteries back home - put them in the freezer for a couple of hours (sometime before first frost) and try to start the vehicle right after you pull it out - if it won't start, buy a new one.

Click to expand...

Would it appear "good" on a load test even if it's on the way out, as you say?

Did you load test it COLD?

How many volts in the system, at the battery with DMM, when the engine is running?

Check this link: http://www.olypen.com/craigh/charge.htm

Yup, load tested it cold.
Oddly enough, it started right up this morning at below freezing temperatures.
Doesn't make much sense to me - up till this morning, the only consistent thing has been trouble at cold temperatures. Now even that might be open to question.

Well, passed load test COLD, so now you should go after the cables/starter/solenoid.

Err, may have misinterpreted your question. I used my DVM in line when the engine had been off for a while, but all tests were in warmer weather than when I've had troubles.
I suppose I ought to put the battery in the freezer after a good charging drive (if my roomies will tolerate that) and see if it still has the cajones to start the car after a coupla hours there.

yossarian19 said:

Err, may have misinterpreted your question. I used my DVM in line when the engine had been off for a while, but all tests were in warmer weather than when I've had troubles.
I suppose I ought to put the battery in the freezer after a good charging drive (if my roomies will tolerate that) and see if it still has the cajones to start the car after a coupla hours there.

Click to expand...

Bingo!

Post back and let us know.