Battery not charging

226 Views 20 Replies 3 Participants Last post by moparado, 1 d ago

Me Fix

Discussion Starter · 9 d ago

Driving home, I noticed the check gages lite. The volt meter was down around 11 volts. Soon it was down to 10 volts and by the time i got back home 9 volts and overhead console was out as was the radio clock. Lucky to get back home. Anyway it seems my at home charger will charge the battery and the engine did start, but after it started the volt meter went to around 11 volts. under a load, the head lights, the volt meter or gage stayed the same. Then I turned on the air conditioning compressor and the volt meter went to 14 volts. Turned of the compressor and the meter dropped back to 11 volts. Seems the alt output is 14 volts when the compressor is on and nothing when it is off. Is this PCM controlled?

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moparado

· #2 · 9 d ago

Yes voltage regulation is controlled by the PCM in modern vehicles.
My guess an intermittently bad alternator or a loose/worn/contaminated serpentine belt could be slipping on the alternator's pulley.
Turning on the AC compressor could of presented enough of a mechanical load on the belt to tighen it up some?
The AC compressor's pulley is free wheeling like an idler pulley until the AC is turned on.
Only a WA guess but i'd eliminate the simplest things first.

Before thinking on replacing the PCM i'd get the alternator tested first.

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Me Fix

Discussion Starter · #3 · 8 d ago

moparado said:
Yes voltage regulation is controlled by the PCM in modern vehicles.
My guess an intermittently bad alternator or a loose/worn/contaminated serpentine belt could be slipping on the alternator's pulley.
Turning on the AC compressor could of presented enough of a mechanical load on the belt to tighen it up some?
The AC compressor's pulley is free wheeling like an idler pulley until the AC is turned on.
Only a WA guess but i'd eliminate the simplest things first.

Before thinking on replacing the PCM i'd get the alternator tested first.

We have 180,000 miles on it. I have a new serpentine belt maybe a year old. Good tension and no cracks visible. This morning when the engine was cold, I started it up. Had 12,3 volts at that time. Started fine. looked at my voltmeter still connected to the battery and it was now at 14, 2 volts. The gage in the dash was at 14 as well. turned almost everything on to put a load on the system and no change. Turned it off and restarted the engine. Everything seemed good. Went up and had breakfast, cleaned up ready to go for a test drive. Started it up and back to 11 volts and it appeared to start dropping. Any load I turned on made no difference. I have a Deka battery 850 CCA, but it's dated 2 of 2017. So it's 6 years old. Maybe time to get a new battery anyway, but could a dead cell cause regulator sense problems? Maybe? I even wondered about the switch under the battery. I think it's called a temperature switch. Maybe it's giving me trouble. I do not have a code reader which might tell me that switch is good or bad. No check engine soon light either. I think I can view any codes per cycling the ignition switch 3 times fast. Any codes will appear where the miles reads, I think! Thanks for the suggestions and help. I have not been on here in a long time. All has been good. In fact we just got a new Grand Cherokee L to replace our GM Acadia. So far so good with it too.

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moparado

· #4 · 8 d ago

If the battery voltage is at 11 volts with as i understand is with a hot engine and dropping could mean a few things:
-The alternator's terminals are loose or corroded
-The alternator has a heat sensitive diode(s) that goes semi shorted or open circuited
-The alternator is bad
-The battery is shot somehow presenting a high enough electridal impedance load to the alternator to sink its output voltage. And yes a shorted dead battery cell can cause this.

Myself if i had this deal i'd get both the battery and alternator load tested before diving any deeper.
Or with that mileage replace them both as a PM if nothing else starting with the battery.

Me Fix

Discussion Starter · #5 · 8 d ago

moparado said:
If the battery voltage is at 11 volts with as i understand is with a hot engine and dropping could mean a few things:
-The alternator's terminals are loose or corroded
-The alternator has a heat sensitive diode(s) that goes semi shorted or open circuited
-The alternator is bad
-The battery is shot somehow presenting a high enough electridal impedance load to the alternator to sink its output voltage. And yes a shorted dead battery cell can cause this.

Myself if i had this deal i'd get both the battery and alternator load tested before diving any deeper.
Or with that mileage replace them both as a PM if nothing else starting with the battery.

Again, thanks for the suggestions. I have removed the battery and will get a new one tomorrow. We shall see if that's the problem. Alt test will be next. I did buy this Overland used with 140,000 mile on it already. I have no idea what the previous owner did to it. I did replace the evaporator coil and blend doors. That was fun!

moparado

· #6 · 8 d ago

Me Fix said:
.......... I did replace the evaporator coil and blend doors. That was fun!

I'll bet that was a fun time!
If my evaporator coil was shot i'd seriously think about getting rid of the vehicle before attempting to replace it myself.

xJoshxx

· #7 · 8 d ago

WJ's have a Battery Temp sensor Built into the battery Tray it tells the PCM the relative temp of the battery to control charging IE don't Nuclear charge the battery if it's hot or too cold.

Seen issues way back when those would go bad or the connector all goofy and it wouldn't charge or was over charging.

Me Fix

Discussion Starter · #8 · 7 d ago

Continuing to follow up here. Installed new battery which was charged at 12.47 volts. Started the engine and dash volt meter went right up to 14 volts. Applied all kinds of load and charge stayed the same 14 volts. Turned off engine and restarted. Back to 11. something volt charge. Adding load made no difference. Took a dead Blow hammer and tapped the top of the alt and change went right back up to 14 volts. I have restarted the engine several times now and charge seems to be good at 14 volts. So maybe the brush set in the alt may be warn or dirty. I am good with removing the alt and taking it apart on the bench, but finding parts could be an issue. Most places want to sell reman assemblies. Retirement is good and it allows time to do things, so I will look into the alt tomorrow.

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moparado

· #9 · 7 d ago

Thanks for the update.

Every once in a while as a last resort, a hammer comes to the rescue.

I agree its probably the brushes or a cold solder joint with one of the diodes.
If its only worn brushes you should be able to find replacements, Google is your friend.

Now for the lingering important and serious question the class has.....
was this a ball peen, carpenter's, sheet metal, wood mallet, brass mallet or rubber mallet hammer?

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xJoshxx

· #10 · 6 d ago

Brass man of culture

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moparado

· #11 · 6 d ago

xJoshxx said:
Brass man of culture

Haha. I vote for a ball peen or carpenter's claw hammer only because those are the easiest ones to find in my case.

Since i have all of the hammer types i mentioned, if i could find my wooden mallet quickly without spending an hour finding it that would be my hammer of choice.

Seriously though, the OP 'Me Fix' found the problem with a hammer which i give him a 'good job man'.

xJoshxx

· #12 · 6 d ago

moparado said:
Haha. I vote for a ball peen or carpenter's claw hammer only because those are the easiest ones to find in my case.
Since i have all of the hammer types i mentioned, if i could find my wooden mallet quickly without spending an hour finding it that would be my hammer of choice.

Seriously though, the OP 'Me Fix' found the problem with a hammer which i give him a 'good job man'.

my 4.7 WJ started one day WOT something in throttle body stuck little percussive maintence fixed it aswell.

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Me Fix

Discussion Starter · #13 · 5 d ago

moparado said:
Haha. I vote for a ball peen or carpenter's claw hammer only because those are the easiest ones to find in my case.
Since i have all of the hammer types i mentioned, if i could find my wooden mallet quickly without spending an hour finding it that would be my hammer of choice.

Seriously though, the OP 'Me Fix' found the problem with a hammer which i give him a 'good job man'.

It was a rubber "Dead Blow" hammer and just a tap! Anyway, because of the 180,000 plus miles and not knowing what the original owner might have done, I decided to order a new alternator from Amazon. My exact number at $93.00. Heck a brush holder and or rebuild kit was going to be half that much. Still waiting on my new one, but while waiting I removed the alternator from the Jeep. Took the back cover off and there was the problem, a massive pile of carbon packed all around the end of the stator shaft. Pulled the brush holder out and I could see that what was left of the brushes was barely enough to touch the stator. Cleaned up the carbon and was amazed at how good the stator copper contacts looked. barely warn. I could put it back together with a new brush holder and most likely be fine. Bearings feel real good as well. Cannot find anyone around here that sells alternator parts. Can find the brushes on Amazon for around $14.00, but would have to wait 3 more days. Hopefully this will be the end of my problem. I think these 2004 WJ Jeeps are starting to age and with that fewer and fewer will be in discussions about issues in the future. Thankfully, many continue to share their experiences and helpful hints. So thanks again .

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moparado

· #14 · 5 d ago

Me Fix said:
It was a rubber "Dead Blow" hammer and just a tap! Anyway, because of the 180,000 plus miles and not knowing what the original owner might have done, I decided to order a new alternator from Amazon. My exact number at $93.00. Heck a brush holder and or rebuild kit was going to be half that much. Still waiting on my new one, but while waiting I removed the alternator from the Jeep. Took the back cover off and there was the problem, a massive pile of carbon packed all around the end of the stator shaft. Pulled the brush holder out and I could see that what was left of the brushes was barely enough to touch the stator. Cleaned up the carbon and was amazed at how good the stator copper contacts looked. barely warn. I could put it back together with a new brush holder and most likely be fine. Bearings feel real good as well. Cannot find anyone around here that sells alternator parts. Can find the brushes on Amazon for around $14.00, but would have to wait 3 more days. Hopefully this will be the end of my problem. I think these 2004 WJ Jeeps are starting to age and with that fewer and fewer will be in discussions about issues in the future. Thankfully, many continue to share their experiences and helpful hints. So thanks again .

Thanks for the update.
So it was a rubber dead blow mallet? Hammer mystery solved.
Yep after 180K miles the brushes finally gave up the ghost.

Keep us updated after you install the alternator replacement.

xJoshxx

· #15 · 5 d ago

Hey also is this a 4.0L or a 4.7L Because if it's 4.7 You can get a Durango Alternator puts out more amps at idle for lights n stuff It's what I did for my WJ 4.7

Me Fix

Discussion Starter · #16 · 5 d ago

xJoshxx said:
Hey also is this a 4.0L or a 4.7L Because if it's 4.7 You can get a Durango Alternator puts out more amps at idle for lights n stuff It's what I did for my WJ 4.7

Yes, it's the 4.7. I appreciate the suggestion about the Durango Alt. If the one I ordered doesn't come in today, which is already two days late from Amazon, I may look up the one you suggested. I still wish I could find the brushes and or brush holder with brushes installed. Mine looks good, bearings feel very smooth and all is already cleaned up . So why not just finish rebuilding it and save some money. The one I ordered from Amazon costs $93.00 plus tax. I did find others at various places, but over $200.00 plus core.

moparado

· #17 · 5 d ago

Me Fix said:
Yes, it's the 4.7. I appreciate the suggestion about the Durango Alt. If the one I ordered doesn't come in today, which is already two days late from Amazon, I may look up the one you suggested. I still wish I could find the brushes and or brush holder with brushes installed. Mine looks good, bearings feel very smooth and all is already cleaned up . So why not just finish rebuilding it and save some money. The one I ordered from Amazon costs $93.00 plus tax. I did find others at various places, but over $200.00 plus core.

Yeah it would be a shame to pitch an otherwise good alternator because of worn brushes.
If this were my deal, i'd blow out any carbon particles from the worn brushes, find the brush replacement set and call it a day with a lot of money saved in the mean time.
Most auto part stores can get them.

However if you intend on keeping the Jeep for a while maybe a new alternator is an option.

xJoshxx

· #18 · 5 d ago

If you plan to do it a 2005 durango alternator will direct swap has 160 amp capacity vs 136 amp It's what i used it's a common swap. or was But For me I had bad experiences from all the Auto part store rebuilt alternators so I only do New.

I had a S10 needed an alt once I went through Advanced auto's entire stock of remans in a day once because i changed it and battery light and output wasnt right. They bench tested them at the store found all 3 i tried failed right out the box.

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moparado

· #19 · 5 d ago

xJoshxx said:
If you plan to do it a 2005 durango alternator will direct swap has 160 amp capacity vs 136 amp It's what i used it's a common swap. or was But For me I had bad experiences from all the Auto part store rebuilt alternators so I only do New.

I had a S10 needed an alt once I went through Advanced auto's entire stock of remans in a day once because i changed it and battery light and output wasnt right. They bench tested them at the store found all 3 i tried failed right out the box.

Thats good to know. Based on that i'll never buy a remanned alternator from Advanced.
A bunch of decades ago i was in the process of rebuilding an old alternator which needed diode replacements.
Luckily i brought my multi meter with me to the part store to make sure the new diodes were all good before buying.
Problem was they were all the wrong polarity meaning anode and the cathode were physically reversed.

Sometimes you get lucky with a remanned part and sometimes not, a toss of the dice.

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Me Fix

Discussion Starter · #20 · 1 d ago

Today, I'm back on the road. I waited over a week for delivery of a new alternator from Amazon. $93.00 for a new one. They don't even want the core. So today, I went to Stans Automative Electrical Shop here in Indianapolis. They rebuild stuff. Anyway, they had the brushes I needed. $4.29 for two brushes. When home, DE soldiered the old ones. And put the new ones in the holder. Put my old alternator back together and mounted it back on top of the 4.7. All is well and saved over $100.00. Thanks Again for all the tips and support troubleshooting the problem. Jeep Garage is full of really nice people!

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