One thing I do notice is that of all the vehicles I have ever had, this one has by far the highest under hood temperatures. All of my previous vehicles had the batteries last about five years. Counting the factory battery, this is the fourth battery that has been on this Jeep. That seems excessive considering I bought it new off the lot with 4.1 miles it in July 2007. When I used to work at an auto parts store, I would often see frequent battery replacement like this when people would put a cheap battery with low cca on a vehicle that was fully loaded with lots of electrical accessories, that is what has me thinking more power. It would be different if the battery was dying in a shorter period of time to where there was an obvious current draw or malfunction in the charging system.
It must be the battery you are using. The 07 came with a 160 amp alternator, and that should be good for re-charging your battery, unless you are really sucking it down for long periods of time.
The thing about high output alternators is that unless you are going to spend the $$$, high output alternators do not produce the nominal amps until the engine speed reaches 2K or more RPM's, so if you are doing alot of stop and go driving the high output alternator is really not charging the battery.
The sears diehard platinum is a very good battery. Contrary to some it is not a re-badged Odyssey, but rather made by the same manufacturer, and that would be EnerSys Corp. The Diehard Platinum has the same specs as the Odyssey but at a lower cost with a better warranty.
Check your battery in a static condition, that is with the engine off and see what the voltage reads. A fully charged battery should read about 12.6 VDC.
Now start your engine and again check. The battery should read about 14-14.7 VDC. If it reads that, your alternator is charging the battery correctly. If it reads under that amount the alternator may be faulty. If it reads above that amount, say 15 VDC or higher the regulator may be faulty and you are overcharging the battery, which could be burning your battery up.
You could also go to a place such as auto-zone and have the battery tested under load, and for any leach draws on the battery. This can be done at most places free of charge.
Ignore if not interested... (Prot - it looks like you don't have the original radio, but this might help someone else if they do a search.)
Originally Posted by jchappy
Have you connected an Ampmeter to the battery system to see if something have a small drain
Originally Posted by 2Five22
I would also consider a looking for a hidden current draw that is depleting your battery if you are taking the above into account and still having problems.
Originally Posted by 1222
If I were you I would keep on trouble shooting until I found an answer to why your batteries are not lasting.
Those comments made me think of this service bulletin:
Service Bulletin NUMBER: 08-001-11 REV. A
DATE: March 05, 2011
SUBJECT: RER, REW, REP Radio Software Enhancements
This bulletin involves upgrading the software on the RER, REW, or REP Radio.
2010 - 2011 (DJ) 2500 Pickup
2010 - 2011 (D2) 3500 Pickup
**2009** - 2011 (DS) 1500 Pickup
**2009** - 2011 (MK) Compass / Patriot
**2009** - 2011 (PM) Caliber
**2008** - 2011 (WK) Grand Cherokee
**2008** - 2011 (KK) Liberty
**2007** -2011 (JK) Wrangler
**2007** - 2011 (JS) Avenger / Sebring
**2007** - 2011 (KA) Nitro
**2008** - 2010 (LC) Challenger
**2008** - 2010 (LE) 300
**2008** - 2010 (XH) Commander
**2008** - 2010 (WH) Grand Cherokee
**2008** - 2010 (RT) Caravan / Town & Country
**2008** - 2010 (LX) 300 / Charger
**2008** - 2010 (ND) Dakota
**2008** - 2009 (XK) Commander
**2008 - 2009 (HB) Durango**
**2008 - 2009 (HG) Aspen**
NOTE: This bulletin applies to vehicles built with an AM/FM/CD/DVD/HDD/MP3 W/ NAV Radio (sales code RER) or an MW/FM CD MP3 NAV Radio - EURO (sales code REW) or an AM/FM CD MP3 NAV Radio - ROW (sales code REP).
SYMPTOM/CONDITION: · The radio may lock up when a U-Connect call ends, this may cause battery drain.
· Intermittent no sound from audio system.
· Repeated **“Updating Channels”** message when in satellite radio mode.
· **iPhone4 (4.2.1) losing Bluetooth connection intermittently and not displaying accurate caller ID information when using UConnect**
Jeep Social Care Specialist
A fully charged battery should read about 12.8-13 volts and as long as the alternator is putting out between 13.2 volts and 14.9 volts it's doing it's job.
To add a little info to that...
A flooded lead acid battery won't hold that voltage for very long after charging stops. 12.6 volts is an acceptable open circuit voltage for such a battery after having been disconnected from the charger for 24 hours.
AGM batteries (which are lead acid batteries, but not considered to be flooded), should read at least 12.8 open circuit volts after charging has been discontinued for 24 hours.
I have been running dual 675 CCA diehard marine batteries in parallel that power a very fast line speed winch, three sets of lights, on board air, stereo, etc., for about 18 months with zero issues. The batteries were under the hood for the first 13-14 months
I am bored and in pain today, so I looked up the specifications of some of my accessories:
My main four channel amp is 50 X 4 RMS
My subwoofer amp is 600 X 1 RMS
Warn recommends a minimum of 650 CCA battery. The battery I keep replacing has 850 CCA, which is more than stock. Here are the specifications on the winch:
12V DC PERFORMANCE SPECS
Lbs.(Kgs.) Line Speed
Current Pull by layer
0 62(18.9) 47 amps 1/9500(4313)
2000(910) 16.3(4.97) 160 amps 2/8650(3927)
4000(1810) 11.8(3.60) 230 amps 3/7920(3595)
6000(2720) 9.31(2.84) 305 amps 4/7400(3359)
8000(3630) 7.59(2.31) 370 amps 5/6940(3150)
9500(4310) 6.67(2.03) 425 amps
I have a couple of sets of lights to hook up to my Jeep, but I have yet to hook them up for various reasons, but still, none of this seems like a big draw. I'll be glad when I can finish healing and start doing things again, because at this point, all I can do is speculate while I lounge around in sweat pants.
I have a blue top that can take the abuse that I throw at it. Including letting it set a couple of months at a time if work really picks up. You have something going on. Either the alternator is not working at peak, the batteries are not top shelf, or you have a small draw that is offsetting the charge provided when you drive it. The stock alternator can handle charging the battery just fine. You don't need a high output or dual battery setup. But it will take time to find the problem.
His 14 Anvil JKUR-X
Hers 09 Blue JK
Kid's '08 Yellow JKU
'13 Black 10A Rubicon JKU
If I remember right, sometime back Chrysler went to having the computer control the voltage instead of having an external voltage regulator or a voltage regulator built into the alternator. Does anyone know if the voltage is regulated by the computer or if it is built into the alternator on a JK?
This is the battery that I replaced the factory one with when it failed after 18 months and is the same battery I keep replacing every 24 months.
It's very frustrating, all of this speculation while sitting behind a computer. On Monday I am getting the staples out of my abdomen and will talk to the doctor about the ongoing intense pain that should have subsided.
Being confined to doing virtually nothing has me looking at possible additional upgrades once this electrical problem is fixed.
I noticed something interesting. With the engine running and the radio turned up about halfway with a song that has a heavy bass (no, I am not into rap, I'm talking more of a hard rock song or something with a lot of percussion), the screen on the radio as well as my headlights dim slightly when the bass hits hard. Maybe I am drawing more than I thought? Both of my amps are made by Alpine, so it's not like those cheap amps that say a gazillion watts when in fact they put out a fraction of it.
Still, I keep coming back to how hot it is under the hood. I swear no vehicle I have ever owned got this hot under the hood. Heat is actually worse for a battery than cold. When the factory battery died, it was winter but every subsequent battery in it has died in the middle of summer. Temperature has been around 98 degrees with heat index of 102 on most days. I see a few heat reduction hoods on the market such as AEV, a few off brands, and now Rugged Ridge. I don't think they reduce under hood temperatures very much, if at all.
A brief history of my last several vehicles beginning with the current one:
2007 JK Unlimited Sahara
2000 Ford F150 V6
1995 Jeep Wrangler 4.0L (damn I miss the simplicity of it)
1992 Mazda MX6 GT Turbo (very quick little car that got 33 MPG)
1972 Pontiac Ventura 307
In the early 2000's, I would frequently rent vehicles, usually compact Japanese cars, due to ongoing problems with my YJ.
None of these got anywhere near as hot as this JK gets under the hood. No, I never put a thermometer under the hood of any of those, but I think when I am able to move around better, I am going to put one under the JK's hood.
Anybody else find that the JK has excessive under the hood temperatures?