I bought a 2010 JKU RHD for my Rural mail route from the dealer Oct. 2010. The battery was bad on the lot! They tried to charge the battery but as soon as I drove of the lot and stopped at a store on the way home it would barely start! Jeep had only 20 miles on it! They put in a new battery and it has been good since.

 

I replaced my stock battery after 3 yrs, and 36,000 miles (est). I noticed a crack in the plastic at the one terminal, so I replaced it with a Duralast Gold. That replacement battery lasted about 17,000 miles, or 1.5 yrs until it was found dead due to a bad cell. I stuck with a second Duralast, and so far all is well...for now.

 

I started a thread after my battery began to fail on my 2012 after 3 months. I couldn't run the radio for 10 minutes with the engine off before the jeep wouldn't start any more. I just replaced with a DieHard Gold. No problems!

 

My 07 has a stock battery - at 123K miles. One of the terminals is weeping, but so far, it's still good to go.

I think average life of batteries in my area is right at 7 years. My wifes '05 battery died this past winter. Mothers '02 two winters ago.

Checking the charging system is pretty easy if you have a DVM / multimeter.

With engine off, battery voltage should be high 12's. Like, 12.8 volts.

With engine running, voltage across the battery should be right around 14.5 volts.

Sometimes batteries just up and die. In the past, they seemed to 'warn' better. These days, it seems like a cell goes bad and that's it. Little warning.

 

Down here in the heat, I'd say 3 years is a reasonable expectation.... these engines(and engine compartments) run hotter than they used to.
Having said that, my '07 original Mopar battery lasted about 1.5 years, and the 1st Mopar replacement lasted about a year. Both were replaced free-of-charge by the dealer(Maxwell).

 

I'm taking my jeep into the dealer tomorrow. They told me the battery should be under warranty (36 months/36k). I'm at 29k right now. I had my roommate jump start it yesterday. Let it charge a bit. Undid the jumping cables. Turned it off. Turned it back on, 3x's. no problem. I go to start it today and it was a no go. Just a few clicks.. I try again and the clicks fade away.

 

I had what I thought was a bad battery. Turned out my underhood light was staying on draining the battery whenever I left it parked for a couple of days. Shorter than 2 days and the battery wouldn't drain enough not to start. Took the bulb out. Battery lasted another two years.

 

UPDATE:
Sorry it has been awhile on the update. My stock battery was in fact dead. Electrical system checked and all charging well and there was no excessive draw when turned off(so they said). Battery was replace under warranty..... I was driving home from the dealership and decided to turn on the radio and nothing-no sound, no numbers, no nothing. I drive back to the dealership and they find the amp is fried. They tried to say it was from my jump staring, but I was listening to the tunes up to the point that I dropped it off initially. They ordered a new amp but it would take a week. I took the jeep home and noted that when the doors were opened the dome lights would not come on. Manual switch worked, but the switch on the stalk did not and the doors did not switch the dome lamp on. When the amp came in they took a look and found out that something behind the dash shorted out as well. All fixed on warranty. Now things seem to be working well. Only issue now is when the pried off the center cover on the dash where the stereo is located the twisted the plastic so it is not flush in all the places it should be..... I can live with that for now.

I am glad I bought the chrysler lifetime warranty. So far I have had a free rental car twice. I have a new battery and amp as well as some electrical dingus behind the dash. Oh yeah I also have new front axle seals as they went out at 5000 miles. Oh I also got new front brakes at 5000 miles as the pads were already worn out?????

I like my jeep but this is the least reliable vehicle I have ever owned.

 

Exact same thing happened on my 2007. Drove me crazy until I loked cloosely at it one night and saw a light under the hood

 

I have had the same problem with every stock battery I have had in Jeeps since 1986.
So...when I bought the COD in 2011, I kept the stock battery for about 6 months then went to Sears and got a DieHard.
Five year warranty, these batteries are worth the money and haven't failed me.
Don't even mess with the Optimum battery. Nowhere as good as a DieHard.