voltage in a car battery?

Question

does anyone know what the required voltage an alternator should be pushing out mine is 14.5. Someone said it should be 12 to 13 anything above 14 is dodgy

Answer 1

14.5 volts is fine and normal all charging systems and batteries put out a little more or less then what is said my car is a 2007 and it is putting out 14.8 according to my power cap so dont worry. and your mechanic is gonna tell you it is normal as well all your equipment in your car is made to work with these voltage changes. if the alternator did not put out a little extra power it would not be able to run all your electronics and still charge your battery

Answer 2

I know 14.3 - 14.5 charge back volts is the norm for Toyota's. When I attended College for Ag. Engineering we were taught 13.5 -14.0 volts was normal. *Any voltages over that would eventually use (boil off) an excess amount of acid / water from the battery.

I took issue with this high charge back voltage with the local Toyota dealer and they said all Toyota's alternators charge back rate is in the low to mid 14's. I found this out when I recently had to add one pint of distilled water to my 04 Camry's battery to bring the water level back up to the filler necks.

I personally do not like this charge back rate because of the excess water usage. It's a problem mainstream people are not aware of. I have a Fluke tester and can check my own and customers systems.
There is no external voltage regulator to play with to drop the voltage back. It's built in the alternator. Also, it (Toyota) is only a 100 amp. alternator to begin with and when they tested the system with all lights and accessories running the serpentine belt was slipping and squealing a bit at idle. The car would not need the high charge rate if they put on a larger sized 130 - 160 amp. alternator to cover the circuit load more efficiently.

Hope I've helped you a little.

Answer 3

How it works: a modern 12V neg. ground alternator charging system. Voltage is not the only consideration here, amperage also needs to be included, for without amperage there is no charging going on regardless of the voltage, well almost.

The voltage regulator (either external or internal) or powertrain control module (PCM, the engine computer) controls the charging rate of this system. Unregulated alternator output can exceed 18V at idle, if the engine rpm is increased, say to 2500 rpm, output goes up as well. I have seen well over 60V coming out of a truck alternator, but that is another story.

When charging voltage is high (up to about 14.8V) current (amperage) is low, this means the battery is close to being fully charged. When charging voltage is low (about 13.5V) current is high and the alternantor is really putting out the amps (this is what happens after you first start your vehicle).

As you drive, the lights, radio, air, etc. are all powered directly from the alternator output, not the battery. The battery is a storage device that just starts your engine, once started the alternator and regulator provide the juice and keep the battery fully charged for the next time you restart it.

In summary the regulated charging voltage will vary between 13.5V - 14.8V depending on the load and the condition and state of charge of the battery at any given time.

Answer 4

Like others said it can not mean anything, a special machine called a load tester puts a draw like a starter on the battery, equal to half of the cold cranking amps of the battery and if it drops below around 9.9 volts *minimum. Just idle it should read around 12.6, the reason it was bouncing must be a bad connection. And disregard the user above. Lets think about this logically it has 12.6 idle, when we put a around 350A draw on the battery the volts go up????? Wow people who dont know anything should not open their mouth. It is also a possibility that a plate has bent over nearly touching another screwing with your reading.

Answer 5

14.5 is probably fine. The battery voltage with out the car running should be 12.5 to 12.8. With the car running the voltage will vary 13 to 14.5 range is good for most cars, but varies depending on model of car and engine rpm. Auto parts store can tell you proper voltage for your vehicle and can test alternator and battery. They normally test for free.

Answer 6

Anything above 14 is to high. As it means the voltage regulator inside the alternator is not working properly and pushing out to many volts.
You need a new alternator.

Answer 7

Hi

13.5 to 14.5 volts is a good output from a healthy alternator and you have nothing to worry about.

You obviously have an all singing all dancing car (ABS, aircon, etc etc...) and the more electrics the higher the output, so don't worry about it.

Regards

Geordie

Answer 8

I agree with Vimto, car batteries, and indeed all car electrics run off 12V, therefore, the alternator charging up the battery with over 14V is probably not doing it any good at all. I would get it checked out by a mechanic.

Answer 9

that sounds normal, with most vehicals, the voltage is around 14 volts with a load on the system and engine running slightly higher then idle.

Answer 10

Older systems gharged at 13.5 to 14.5.

Modern batteries actually need about 14.5 to 14.8 to get best performance, but don't worry if you only have 13.5 , it just takes longer to fully charge!