If the battery light is on then there is a good chance that the voltage is not at the expected 14 volts.
If you can get a multi-meter you can check the battery terminals when the car is running and see if you have 14 volts on the battery. (12 volts when the car is off)
Lots of cars turn off now when you remove the negative terminal so that's not a good alternator test.
Also keep in mind that a battery can run a car for quite a while. Our race car doesn't have an alternator at all. It runs a 50 lap race on the battery running a V8 engine at up to 8,000 rpm with a strong ignition system and the fans and a few other things so a battery can run your car for a while before you really notice the issue.
I would suggest at the least, get a multi meter on the battery to see that it's actually getting 14 volts from the alt. when the car is running. And maybe take it to a shop just to get a proper load test on the alternator.
1. NEVER, EVER, run a modern car without the battery connected. The battery removes voltage spikes that could severely damage modern electronics (especially field effect transistors, especially MOS and CMOS). Old cars don't have such fancy electronics, so old timers were able to get away with running a car without the battery connected.
2. It is normal for lights to brighten when the engine is revved to higher RPMs. This is because the voltage regulator is not perfect, so it doesn't keep the voltage perfectly stable. In fact, if the lights brighten, it "almost" proves that the alternator is working well and charging the battery.
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The fact that the engine died when the negative battery cable was removed means that the alternator was not charging sufficiently. Likely the alternator (or voltage regulator) is bad.
You mean you did not try the mixture of powered bat ears with fish eyes spread in front of the car to see if the mixture turns blue? Since you are unable or unwilling or actually believe that your name or any other name needs to be capitalized and since you are unable or unwilling to have a mechanic do a FREE test of the alternator with a voltmeter and since you are unable or unwilling to accept that all of what you have done is based on gossip, rumor and teen fantasies as to cars, then, why are you asking here for? What could possibly anyone say to you about this issue? All cars have the battery light ON during the start sequence. Prior to the START position of the ignition, the car's electrical system self checks many systems. The lights in the dashboard sequence ON then OFF except for a few and the battery icon, red in color and in the shape of a battery, remains on to signify, as designed, that the battery is powering the electrical system of the car. Once the engine starts, the alternator powers the car and the sensor that measures voltage that activated the battery icon (why people call it a "light" is from decades and decades ago when cars had alternators and idiot lights) detects higher voltage than 12 volts and it turns off battery icon. All systems that have sensors are subject to that sensor having a fault. But, Dude who cannot capitalize your own name, it is so simple to go by an auto repair shop and to have a technician do this test FOR FREE that I have to ask, why have you not done this? At times I am amazed how young kids with cars will not ask family, friends or local auto technicians preferring to text about anything and everything. This addiction is not a good thing. I suggest you reconsider your approach to car issues. It takes training, certification, proper check out of concepts of science and practice and more practice to be certified as an auto technician. Would you agree?
With the car running ,hook up a voltmeter across the battery terminals.Running voltage should be 13.5-15.5 volts.If this checks OK,do a load test on the alternator by gradually loading up the voltage requirement by turning on accessories like the headlights,blower fan,and wipers ONE AT A TIME.The reading on the voltmeter should NOT show much of a change.This would be a good indication that the alternator is charging,that the voltage regulator and the diodes-rectifier is good.Electronic parts are very sensitive to sudden voltage changes so don't ever test a vehicle by disconnecting a main battery cable while running.If you are still showing good on the above checks ,inspect the small red wire going to the BAT terminal on the alternator.Check it for breaks or a rub spot that will cause it to ground.
A battery light on the dash is usually an indication of a power issue, either a dead battery, a bad alternator, or another issue in the power wiring. If you have a local auto parts store around, many offer free testing.
From what you have stated, I am leaning towards the alternator being bad. A free test at the auto parts store will tell you for sure. Safe travels.
It would help if we knew the make, model, engine, mileage, etc. l'm guessing your vehicle has 80,000 or more miles, and the alternator finally let go. Either test it yourself with a voltmeter (should read about 12 to 12.6 with engine off and around 14 with engine running. Lower voltage running than not running is a near sure sign of bad alternator. Costs around $65 rebuilt, and installation takes half hour the first time you do it. You tube will have a video for nearly every model.
Most parts stores will test for free. A qualified general automotive who will charge around $200 or so, including everything. Choose carefully -- you want one that's been open a while, with good rating at BBB.
Do an OBD2 code check to see what has failed. The charge light might be on for some other reason. Check all your fuses before you buy more expensive parts that don't need replacing. If your alternator isn't turning, it can't charge the battery, so is the belt still on it? A good service station can do more comprehensive checking.
A new battery has nothing to do with why the *alternator has stopped charging the battery which IS your problem.
Read the owners manual in the glove compartment under charging system or alternator and it will tell you the same thing or the dealer of your car.
So by now hopefully you know that to test an alternator you need a voltmeter! At least 13.7 volts at 1500 rpm. If it's only around 12.5 you have a diode in one of the 3 circuits out and are only surface charging your battery.
Battery light has been on for two days. I have a new duralast battery. Then I tested my alternator. I did the headlights test, ur suppose to push on the accelerator with your foot while in park, and if your lights dim,flicker or get brighter while ur doing this then the alternator may be bad, well I did it and lights did not move or flicker or looked dim so that's good. Then I did the alternator-battery test, as the car is running, u remove the negative terminal and if the car dies or stalls then the battery isn't getting enough electricity, I removed the black negative terminal and my car did shut off. I have driven with the light on to and from work twice this week which is 23 mins from where I live, so that's a total of 93 mins And 40 total miles . Car never died while I was driving it, nor did it sputter up and down while I was stopped or driving. Also I was able to start the car without it hesitating,clicking,or sputtering. I'm thinking its a bad wire or bad terminals. Some help please?
So by now hopefully you know that to test an alternator you need a voltmeter! At least 13.7 volts at 1500 rpm. If it's only around 12.5 you have a diode in one of the 3 circuits out and are only surface charging your battery.
The warning light being on indicates a problem with the charging system. It sounds like the problem might be a stuck regulator, so the battery might not necessarily be left with no charge, just no matching between the rate of charge and the rate of discharge. It will cost very little to get an auto electrician to check this.
I never heard of the " headlight test "............and you should NEVER preform ther " unhook battery " test. You can damage the electrics, because the battery acts as a " buffer " for voltage spikes from the alternator....That test goes back to the days of a " generator " on the car, and no high-tec electronics
Bottom line, I ' ll bet you have a defective alternator,...it may work part - time, or just a little bit
So by now hopefully you know that to test an alternator you need a voltmeter! At least 13.7 volts at 1500 rpm. If it's only around 12.5 you have a diode in one of the 3 circuits out and are only surface charging your battery.
Have you not heard of auto parts stores that do free testing. This old tail about headlights and disconnecting the battery cables are so out dated and the battery thing can cause major damage to the sensitive electronics in cars today. Go get it tested. You don't have another two days of driving before it lets you down.
A new battery has nothing to do with why the *alternator has stopped charging the battery which IS your problem.
Read the owners manual in the glove compartment under charging system or alternator and it will tell you the same thing or the dealer of your car.
You are lucky since your alternator must be bad or the fusible link is blown. If it were working you would have likely blown your ignition module and alternator diodes by doing something unwise as pulling off a battery cable with the car running. i watched someone do that once it wasn't pretty!
Connections, battery voltage, and state of charge.
Your testing is flawed and sounds like you need more competent help.
Have your electrical system tested by competent service technicians, or you will throw good money after bad trying to use a confused mish mash of incorrect methods for whatever kind of make, model year, and engine and trans you are trying to fix.
Circuit protections like fuses, fuse links, etc can be suspect after your type of description, as well as damage caused during your method of guess checking.
That is not a valid test. Stop in a local garage or auto parts store where a charging system check is usually free and takes just a few minutes. Your testing is rubbish.
That is not a valid test. Stop in a local garage or auto parts store where a charging system check is usually free and takes just a few minutes. Your testing is rubbish.
That is not a valid test. Stop in a local garage or auto parts store where a charging system check is usually free and takes just a few minutes. Your testing is rubbish.
Have you checked that the alternator belt is too loose and it is slipping? Simple check.
How squishy are the seats?
your car is almost dead!
