Really really weird

alternator?

 

Don't guess. Start your diagnosis. Start with output voltage of the alternator.

 

Similar thing happened to me. I’d test the battery first if you already replaced the alternator. I ended up replacing the battery and rebuilding the alternator and I’ve had no issues since.

 

Sounds like alternator to me, my 95 did that 7 years ago and I had to rebuild my alternator. Definetely test it to make sure you find out what it really is. I had to drive from Santa Fe to Denver on just a battery and it was not fun, charged it in Raton and Colorado Sorings to make it home.

 

That’s why I’d think it’s the battery particularly if you already replaced the alternator. Alternator is generating enough to keep car running, but nothing much else for accessories.

 

Bob, did the battery light come on in the dash display? If yes, the alternator is bad or connection, devices between it and the battery failed. If so, The car ran on battery power alone. Not enough to power all the electrical devices. Just enough to keep the spark plugs firing away. Eventually it will die. You will not be able to start the car again after a shut down if you can get the windows to roll up.


If the battery light in the dash did not come on, the alternator is good. The “weird” issue should not occur even if the battery less than half capacity because the alternator supply the electricity as long as there’s no loose connection or other failures in between. I’m basing this on the fact that alternators are sized to match, most cases exceed the car electrical demand. While electrical power is drawn from the battery, the alternator fills it back up at the same rate. Technically speaking, the car and all it’s electrics continue to run even when the battery is dead.


Under no circumstances do not disconnect the battery while the engine is running to test the alternator. Nearly all car electronic devices have a voltage tolerance between 11.5v-13.8v. Alternators output voltage is slightly higher. Disconnecting the battery potentially expose the system to a shock treatment.


Testing a battery requires more than just a volt meter. The threshold between a good battery and a dead one is very small if voltage is the testing method. A battery may be full, half or less than half still put out the same voltage. An accurate condition of a battery can only be determined by a load test to verify the ampacity and its ability to hold a charge.

 

Whenever electronic devices seist to function at the same time, usually something happens at the power source and or the connection and devices in between. Let us know the outcome.

 

When my alternator went, I was driving down the street and I noticed that my fans stopped and turn signals started ticking slowly. I was down the street from the dealership and tried to get there, it went about 2 miles before all the electrical turned off piece by piece, and then the car stalled out. Thankfully, a rebuilt alternator was not expensive. I want to say it was less than $300.

 

I think that battery is fine it just reads in Canadian volts

 

The 348, minus a voltage gauge is lame. I don't trust waiting on a warning light. Lol, even my 280z had this, and builders left it out as a catastrophe in modern times. I hate these builders. If the battery is over 4 years old replace it. Not worth the hassle unless you drive your vehicle daily the batteries that sit even with a current trickle charger.. go bad. Replace without question and check alternator charge rate. If it can't get you to 14v it is deteriorating so I would replace both alt n Batt... as much as quality is available it don't matter to me as long as it charges to 14v or slightly lower when hot.

Dave

Sent from my 0PJA2 using Tapatalk

 

Glad it all worked out.

For reference. A good car battery typically puts out 12.6v plus or minus a tenth. An alternator puts out roughly 14v. With the engine running, the alternator and battery form a parallel circuit. If a voltmeter placed across the circuit, the reading will show the average between the two sources. 12.8v in above post is the net of the battery and the alternator with the engine running. The 11v reading is the battery alone with the engine not running. The 11v compares to 12.6v seems small but it does indicate the battery is aging and may not adequately hold a charge for reasons as follow.

The inner working of cars batteries are the dialectic plates sandwiched together but insulated from one another. Typically the plates are grouped in cells which is a battery itself. If each cell produces 2.1v, 6 cells connected in series produces 12.6v, a typical car battery. A fully charged battery has abundant of electrons on one plate. The plate next to it is devoid of electrons. This arrangement replicates according to how many plates there are in a cell. Once charged with electrons on half the plates, the potential differences with the plates devoid of electrons next to it is stored electrical energy. When an electrical load such as a light bulb is placed across the potential differences (+ -) of the battery terminals, electrons flow across the plates discharging the battery. The rate of discharge depends on the size of the load in amps. A typical car battery charges and discharge thousands of time over. Whenever the engine starts, the battery discharges. The battery charges when the engine runs. This repetitive charging and discharging overtime breaks down the dialectic plates insulating factor allowing unwanted flow of electrons between the plates. If the flow is large enough, the battery will no longer hold a charge thus will not store electrical energy. It’s dead. This explains the voltage drops to 11v when the engine is cut off as Bob stated in his post. Additionally, heavy use is not the only degrading factor. The dielectric plates are not 100% insulated from one another. Small among of electrons leak between the plates occur naturally. All batteries deplete overtime. That’s is why a trickle charger is needed when it sits for a long time.

As I mention earlier, a volt meter is not the correct instrument for measuring batteries condition. A battery may measure 11.5v or some value in that range. As soon as a load is connected, it reads zero or some nonfeasible value. A dead battery nearly depleted of electrons will give a voltage reading. Sometimes in the 11v range. From experience on the matter, a voltmeter is only useful to measure the present of voltage and its magnitude of a known potential.