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2009 Jeep Patriot - A battery every 2 months

I’ve had seven new batteries installed in a year and half. I’ve also had seven tech’s and mechanics look at it and not find the battery drain. It’s only got 62,000 miles and runs like a top once I connect the battery disconnect and jump it. A new alternator and uni-pulley system was installed.
I’m 10 miles from the Fiat/Chrysler headquarters, and this WILL be my first and LAST Chrysler product out of 27 vehicles. Best advice was it was a factory problem.

10 year old car with unknown maintenance history. Did competent mechanics check for parasitic drain? Electrical gremlins can be a pain to find

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Even with the battery disconnect dis-connected, your battery is still dying?

How often and how far do you drive?

Did you have the battery tested before replacement?

No- but I’ll take a voltage drop, get 12v, and it’s still not enough to turn the starter without the battery jump.

I’ve been a Chevy guy my whole life. Should have stuck with the plan!

No- but I’ll take a voltage drop, get 12v, and it’s still not enough to turn the starter without the battery jump.

I’ve been a Chevy guy my whole life. Should have stuck with the plan!

This is not a Jeep problem. This is a can’t diagnose it properly problem.

12 volts does not mean anything if the amps are not there to back it up. This is an alternator control problem or a heavy parasitic draw issue.


What voltage does the battery measure when the engine is idling, immediately after starting a cold engine, first start of the day? It should be in the 13.5 - 15.5 volt range.

If that’s ok then most likely there’s something staying on after the engine is turned off that’s draining the battery. That should be simple enough for a good shop to figure out. Measure the battery drain current. It should be 50 mA or below once all the computers turn off after turning off the engine. Might take 30 minutes or so for the computers to turn off.

If that tests ok, then there must be something turning on later, in the middle of the night. There’s test equipment available that will record the current vs time all night long, but many shops don’t have it. But a cell phone can be programmed to take a photo of the display of a simple amp meter, say every 5 minutes. Reviewing those photos the next day would show when the drain current increased.

If you know there’s a drain current but don’t know what’s causing it, the normal way is to start removing fuses. A better method however is to use a laser-guided infrared temperature gadget. Just point the laser at the fuses one by one. The circuit with the drain current will have the warmest fuse.

Common things that cause this: glove compartment, engine compartment, trunk light staying on; faulty door switch is making the computer to think somebody is getting into the car; wind is blowing on the door; stuff like that is the most common cause. Alternator diodes can fail and cause this too, which is more difficult to diagnose.


There is either a parasitic draw or a bad voltage regulator. Is the voltage regulator separate from the alternator on Jeeps?

Read what George wrote.

George@San Jose

Thanks. that’s the most level headed answer to the problem I’ve seen in two years of looking online. I have all the equipt. you mention and will try it.
This is a factory/design problem. I just don’t want to spend $1200 to repair it. I’m 65 and retired, so I only use the vehicle 1-2 times a week. I also live in an apt. so any self repairs are in my parking lot.

what would be fixed/replaced for $1200? has someone already given you an answer to what your problem is?

You seem to be stuck on blaming the vehicle instead of the people who are misdiagnosing it.
The first one might be given the benefit of the doubt but not the last 6. All car makes and models have gone through similar issues

If those people say they can’t find a problem and blindly replace the battery on a guess then they are not very knowledgeable so to speak when it comes to electrical issues. There is simply no way on God’s Green Earth that you got 7 bad batteries in 1.5 years.

There’s methodical process to this.
Load test battery,
Test alternator output.
Test for excessive parasitic battery drain. I do not know what the factor spec on the drain is but consider it around 50 Millamperes after everything goes to sleep.

It just boggles my mind that it got to this point and I have to wonder if the alternator replacement was also a wild guess on someone’s part. And then to add a battery disconnect to boot? That shold not be needed. Just my humble opinions.


Has anyone load tested the starter ?

I’m no Jeep fan but…
It shouldn’t be brain surgery for competent technicians. Maybe you need to go elsewhere.