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Not necessarily. There are a lot of factors that can keep you from reading 14 volts at the battery, such as corrosion in the cable from the alternator to the battery.
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Is it the battery or the alternator that is bad on a zx7r that shows 11.77 volts while idling at 3000?
Unless the battery is shorted or sulfated and will not take or hold a charge, most likely the alternator is bad
Can a car battery be bad if its still pushing 12 volts?
Yes. A fully charge battery will read 12.6 volts with engine not running. A 75% charged battery will read 12.4 volts. At 50% charge, it will read 12.2 volts. At a 25% charge it will read 12 volts, but that will not be enough to even start the engine in most cases and unless the alternator is bad the battery is defective. With the engine running you should read 13.5 to 15.5 volts at the battery. Any less and the alternator is defective.
Battery won't charge?
Either the battery is bad and won't accept a charge or the alternator is not putting a charge into the battery. Have the battery tested. You can hook up an inexpensive volt meter to the battery while the car is running. You should see from 13.5 to 14.5 volts if the alternator is working properly. If it is less than 13.5 volts then the alternator is not charging.
Can a bad alternator cause a battery to be unchargable?
Yes, it can ruin the battery by overcharging it. If you are reading between 13.5 to 15.5 volts at the battery with the engine idling then more than likely the alternator is good and you battery has a dead cell. A fully charged battery will read 12.6 volts with the engine not running.
Why would your alternator be pushing to many volts to my battery and how do you fix it 1986 fifth avenue?
Bad ECU, replace.
Why would a car with a new battery not start and once you give the battery a jump it starts it's a 1999 Mercedes c230?
probably has a bad alternator. With the car running use a digital multimeter an you should have 13 + volts (as high as 14.5+) at the battery terminals if the alternator is working. If only 12 volts or so then check the alternator.
Why wont your brand new alternator recharge your battery?
Maybe the battery is defective. Check the voltage at the battery terminals with the engine running at idle. You should get 13.5 to 16 volts. If not the alternator is defective or the voltage regulator is bad. If you are getting the correct voltage, the battery is bad or the connections are corroded.
Would a bad alternator on a 1999 Grand Cherokee Jeep Limited keep discharging a brand new battery?
=== === Some types of electrical shorts do cause the battery to discharge. But usually a bad alternator just does not charge the battery. Or does not put a large enough charge back into the battery. This causes the battery to discharge when you start and run the motor. The spark plugs and other things need electricity that would usually come from the alternator is now coming from your battery. If your bad alternator is not recharging the new battery, the battery will soon fail to start or run your vehicle. You need to have your alternator tested. It should be putting out at least 12 volts, usually around 13 to 15 volts.
What is the battery voltage for a 1984 Mercedes 380 SL?
12 volts shut off. Running it should read around 13.5-16 volts at the battery posts. Any less and the alternator is bad.
How can you tell if your alternator is bad on dodge grand caravan?
Start engine and measure volts at battery, it should be at least 13
Could a bad battery turn the check engine light?
A bad battery will not turn on a check engine light. A bad alternator however will. Have your vehicle checked and see if the alternator is putting out at least 13.5 volts and if so there may be another issue causing the light .
If an 88 Accord DX has a new battery but will not hold a charge do the battery cables need replacing?
A bad alternator will run down the battery. Maybe. Lets check the simple stuff first.How do you know that it IS charging in the first place? Get a voltmeter (VOM) and measure the voltage of the battery when the car is off. It should be more than 11.5 Volts. (Or it is really discharged battery). The start the car and measure the voltage again. It sould be at least 13.5 Volts up to about 14.5 volts. If not then the alternator is not giving enough voltage to charge. If it is, then it could still be a diode in the alternator that is bad. You cold have some accessory or light that stays ON somwhere draining the battery. It could be a bad battery. It could be a bad set of battery cables.
