98 GRAND CHEROKEE BATTERY BEING DRAINED

As indicated something is killing my battery, Thought it was the battery myself because I had just recently replaced the headlight module after is shorted out and left the headlight on to drain the battery. Now the battery is being drained. Brand new battery drained in three days. Any ideas. Hate electrical don't want to pay 85 an hour for diagnosing.

Matt 0|||||||0 Tact is the ability to describe others as they see themselves

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JEEPR
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Dick

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L.W.( ßill ) Hughes III

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mic canic

Welcome to the whole point of usenet where you develop new skills and then share them with others.

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

diagnosing.

Reply to
Dave Milne

Don't really trust garages, took my battery to get tested, told me it had a defective cell, So I say ok and buy another one, bring it home and install it, dead in three days, If anybody is just going to miss diagnose I can just as well as a garage I'm paying 85 an hour to screw me over.

diagnosing.

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JEEPR

Reply to
L.W.( ßill ) Hughes III

Well, you have learned something now, Bill :-) Seriously, I think it's better to read the manual and learn from a mate than it is too always book stuff into the garage, and not learn anything. While you will screw up from time to time, you win out in the long term. While not deluding myself as a great mechanic, I thank my Dad frequently for what he has taught me.

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

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Dave Milne

"you have learned HIM something now" I meant...

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Dave Milne

Reply to
L.W.( ßill ) Hughes III

Well I have diagnosed it down to the air conditioning clutch solenoid being engaged all the time. not to sure what would cause it, I pulled the relay in the power distribution box and re installed it, now fault has disappeared for now. As a side bar my new battery dropped to 9 volts and was boiling over in the jeep. The out put from alternator is 14 v. Now the garage wants to recharge it, I say it was defective because a battery should never loose its voltage, but they would not listen to me.

Reply to
JEEPR

L.W. ("ßill") Hughes III did pass the time by typing:

Make that a digital volt meter, the analog ones arn't safe for using on some sensors.

Reply to
DougW

A battery will always lose voltage as it discharges. That's why your flashlight gets dim as the batteries get used up. It's also normal for the alternator to charge at around 14 volts when the battery is discharged. This also depends upon outside temperature. Let the garage charge the battery.

Dick

Reply to
Dick

a battery never looses voltage, it will loose its capacitance to delivery current that why the flashlight goes dim, measure the voltage on a deed flashlight battery and it will read 1.5v, but the potential (voltage) will remain

Reply to
JEEPR

Reply to
L.W.( ßill ) Hughes III

That is absolutely not true. You apparently haven't measured the voltage on a dead or dying battery. I have measured hundreds, if not thousands of batteries in my lifetime, and I assure you the voltage across the terminals will decrease as the cell(s) go dead.

Just for drill I measured the voltage on two AA cells I took out of a wireless mouse because the mouse no longer worked. The batteries measured 1.022 volts DC with no load on a $350 Fluke DVM calibrated by Fluke. That's a long way from 1.5 volts. The same is true of any battery.

As I said before, let the garage charge your battery. There is probably nothing wrong with it, except that it needs charging.

Reply to
Dick

Reply to
L.W.( ßill ) Hughes III

L.W. ("ßill") Hughes III did pass the time by typing:

They work for most tests but some of the newer fiddly bits like the crankshaft position sensor, can be blown if you do an ohm test on em with an analog meter. The analog meters use too much current to measure the resistance load.

Reply to
DougW

Just to claify a few things.

All batteries have a power curve and it varies from model to model. Here is one for a standard AA battery. (e91)

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Flip to the second page and look at constant power discharge.

(I went through a lot of this figuring out what batteries would last longer in my GPS unit) The Energizer and e2 profiles are almost identical so the only thing you got when paying out the noze for an e2 was a warm fuzzy.

Anyhoo, back on line...

Feel like watching a slide show?

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Optima self-discharge curve.
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Hope that helps clear things up.

The only sure way to test a car battery is a load test. Most PepBoys and probably C-Tire (Tyre?) :) will have a setup. This is a computer that charges the battery then does a controlled and timed discharge.

FWIW, I've brought dead cell batteries back to life by using a charger (high amp) and a volt meter to bring the battery up to the service maximum 5-10 times in a row and then using a low amp trickle till all cells bubbled the same. I don't suggest doing this without eye protection because you will bubble the cells quite a bit and that's acid that is popping out even if you can't see the microsopic drops.

Reply to
DougW

Well Dick The garage called and turns out the battery was defective as I indicated and I was given a new one. I don't want to flame anyone or blow my own horn, but I have had education in power distribution for aircraft and lead acid battery maintenance was part of it so I know what I talking about. When it comes to present day automotive I am just as ignorant as most with the many different modules and computers that control systems, that is why I am here to draw on the experience of others. Now I just have to figure out what is activating the solenoid, do not have wiring diagrams to follow. Give me a good schematic not block diagram and a simple meter and I would not have much of a problem except for the modules and computers. Seems like this thread is getting out of hand so I will start a new one when I have the time to continue trouble shooting the fault.

If measuring dead batteries makes you an expert well good for you.

Matt 0|||||||0 Tact is the ability to describe others as they see themselves

Reply to
JEEPR

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