0
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.
What else can I help you with?
Will a battery still have 12 volts if it is bad?
Yes, a battery with only a 25% charge will read 12 volts. A fully charged battery will read 12.6 volts.
Why would your alternator be pushing to many volts to my battery and how do you fix it 1986 fifth avenue?
Bad ECU, replace.
Is 13 volts on a battery mean your alternator is bad?
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.
Why is your Cadillac STS still reading 11.9 battery volts?
Bad alternator? A fully charged battery should read approx. 12.8 without engine running With engine running should read approx. 13.8-14.2 volts
Would the voltage regulater keep from charging your battery?
The voltage regulator regulates the output of the alternator or generator, depending on what you have. today it is mostly alternators that are regulated to 14.4 volts, but you are fine if it is putting out 13.25-14.9 volts lower than 12.5 volts will not charge a 12 volt battery and over 15 volts will boil or explode the battery. 6 volt systems will usually charge 6.5-7 volts. if the charging system is putting out that voltage, and the battery is still going down first check for bad connections, and charge the battery, if that still does not fix it have the battery checked, most parts stores offer some form of a test for a battery and can lead you closer to the problem if the battery is not the problem.
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.
How do you test a John Deere alternator to see if it is putting out a charge while still mounted?
Your 12 volt battery should be about 12.5 volts without the engine running. Test and verify it is. Now with the engine running test again, Voltage should now be around 13 to 14 volts. If not, then your battery or alternator are bad. To check a battery try charging it with a battery charger.
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.
Why is your 2002 Oldsmobile intrigue battery light still on after replacing the old with a new?
Sounds like you may have a bad alternator - check with a voltmeter A fully charged battery should read approx. 12.8 volts without vehicle running With vehicle running reading should be approx. 13.8-14.2 volts
Is your battery bad if the voltage reads 10.5 volts dc?
First it would depend upon the type and voltage rating of the battery. If it is a lead acid battery, I would recommend charging it to its recommended voltage and load testing it. A fully charged 12 volt automobile battery should read 12.6 volts. A battery that reads 10.5 volts is completely drained. If the battery is fully charged and only read 10.5 volts it needs to be replaced.
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.
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
