Just today I replaced my OEM battery with an Optima Yellowtop D34/78. Had one in my TJ and loved it. I saw the article above and I probably would have gone Sears Platinum had I known. I'll keep my fingers crossed that the training for the new workers in Mexico was done right...

 

I just had to replace the battery in my 07 because of the same problem. Mine started to have difficulty starting and soon after didnt hold a charge at all. Replace it now before you get stranded. Or carry a booster box around like I did....

 

After reading these posts and doing some research, I have to say, much as the Optima has filled my needs and the two I've had since 1996 both have been a very reliable battery, my next battery will be the DieHard Platinum, either P-1 size 34 ot the P-4 size 34/78. Although it is a bit more at about $190.00, it appears to have, as some have posted, more CCA's and a better reserve, as well as a better warranty than the Optima.
In addition since most Optima's are now manufactured in Mexico, and the Platinum DieHard is according to Sears Holding Corp, being manufactured in Warrensburg Mo. under EnerSys USA, and as "mdnky" posted, this is the same company that manufactures the Odyssey. In the past I've looked into the Odyssey, however thought it to be overpriced. The lowesr cost I could find for the PC1500 (single terminal set) was $257.99, and for the PC1500DT (dual terminal set) $270.84
The DieHard Platinum P-1 group 34 (single terminal set) is $189.97, and the P-4 group 34/78 (dual terminal set) is the same price.
Seems to me the DieHard Platinum is the way to go. At least for me.

 

I'll get a Diehard in 2013...

 

Die Hard Platinum P-1:


If you're luck they sometimes have them on sale.

 

Ahh, that makes sense! I was scratching my head wondering how some people have claimed to get 5-6 years out of a battery (one poster claiming 5-6 years is "normal") when I have never, ever got more than 2 or 3 years out of one no matter the brand or quality of battery, the type of vehicle or how often I start it or let it sit. Then again I live in Sydney where it never freezes (rarely gets below 10C or 50F in winter) and the temp is usually 25-35C (77-95F) for most of the year.

I've noticed a few threads here about heat building up under the hood of the JK (& people fitting aftermarket cooling vents) so maybe this is contributing to the percieved short life of JK batteries...

 

I just replaced OEM battery with the Sears Platinum last Friday. Has 880 CCA while OEM was 600. Also it is a jell battery and you have no place to add water like the OEM. Bought it at Sears for $180 and free installation.

 

Actually it is an Absorbent glass mat (AGM) battery.
Just sayin'

 

My answer is 3 years, 1 month, and about 10 days. Just replaced the battery this morning!

 

Under normal conditions I would replace it at the 3 yr. mark. In your case if everything else checks out you might want to replace it now. Try re-setting the cables first to make sure you have good contact. Have the alternator checked.