Alternator Issue

[windrunner]

for the past year or so the alternator guage has moved from normal to a charge reading...

used a voltmeter to check alternator and @ 2000 rpm the output varies between 14.56 and 14.58...

at this level will it burn out the battery...

thanks in advance for your response...

windr

[Mike Gerber]

No, those voltage readings are perfectly normal.

Mike

[windrunner]

Originally Posted by Mike Gerber

No, those voltage readings are perfectly normal.

Mike

thanks mike, even over a prolonged and constant period of time...

[hill8570]

Like Mike said, 14 1/2 volts isn't really out of spec. If you throw a bit of load on your battery with the engine off (say, turn on your running lights), what's the battery voltage?

[djb2]

Those readings are very high.

While the optimal voltage varies with temperature and battery use, the upper end 14.1V. Perhaps 14.2V in very cold conditions where the charge acceptance is low. In normal conditions the voltage should be around 13.8-13.9V

[ekopel]

I've been working on toyos and lexi for a while. Everytime we test a battery/alternator, we look for those kind of values. They are perfect. That is what you should be getting. I have a volt meter in my car and I get about 14.3-14.4 on average. Your battery is probably what is providing that charge, the alternator has a high amperage, but the battery provides the essential voltage. More importantly, you should check your cold cranking amps on the battery (to test for a bad battery) as well as running amps on the battery.

IMO, your more than fine. If you want to ensure that it stays running well, do what these guys have suggested:
Keep contacts clean/replace if needed
make sure you are not losing power anywhere from any peripherals attached (subs, etc)

Don't bag: Everyone has seen different values, but this is what lexus mechanics look for in terms of voltage.

[hill8570]

Originally Posted by djb2

Those readings are very high.

While the optimal voltage varies with temperature and battery use, the upper end 14.1V. Perhaps 14.2V in very cold conditions where the charge acceptance is low. In normal conditions the voltage should be around 13.8-13.9V

Um, no -- cool engine specs are 13.9 - 15.1V at the generator (check the FSM if you don't believe me). ~13.8V is the typical voltage at the battery with the engine running.

I'd still like to know the lightly-loaded voltage at the battery. I've seen more than one 4-cylinder Camry keep working happily with a duff battery cell...bit slower cranking than normal, but other than that, nada. Put a bit of load on the battery, 'tho, and you're looking at something closer to 10V at the battery, instead of nominal 12-and-a-half to 13.

[JohnGD]

I thought the voltage regulation range is about 13.5-14.5v?? So within this range it should be normal?

Originally Posted by windrunner

for the past year or so the alternator guage has moved from normal to a charge reading...

used a voltmeter to check alternator and @ 2000 rpm the output varies between 14.56 and 14.58...

at this level will it burn out the battery...

thanks in advance for your response...

windr

[JohnGD]

also, you can take the car to Autozone. They'll check the alternator and battery free.

Originally Posted by windrunner

for the past year or so the alternator guage has moved from normal to a charge reading...

used a voltmeter to check alternator and @ 2000 rpm the output varies between 14.56 and 14.58...

at this level will it burn out the battery...

thanks in advance for your response...

windr

[windrunner]

Originally Posted by JohnGD

also, you can take the car to Autozone. They'll check the alternator and battery free.

hey john,

in my neck of the woods there is no autozone so i went to a local mechanic who did a load check and told me i needed a new battery and then my battery charge gauge meter would return to normal....

little did he know prior to taking the car in to him i anticipated that as a possible cause so i put a brand new battery in for a week or so...

since the new battery made no difference i switched to my old battery and thought the mechanic would give me a better diagnosis...

the point that i am getting to is the mechanic charged me $50.00 to tell me something i already knew...

[Hajoca]

My scangauge reads 14.4V idle to 14.8 V driving with no additional loads other than daytime running lights.

It drops with headlamps, defogger and vent blower on. Power windows also draw a lot of power.

[trentmeyer23]

A good way to test a battery is to not have the engine running, and with headlights on, it shoud read no less than 11 Volts, under cranking conditions(lights off) it should not drop below 10.5V (9.5V or lower will require new battery), 14.4-ish charging, and should sit between 12V and 12.6V not running, Slight increases and decreases are not a huge concern. The cause could possibly be damaged or worn cable, or worn or damaged brushes amoungst others in the alternator. Its hard to diagnose without the vehicle, best bet, go to an auto electrican.

[SexieWASD]

My voltage varies between 13.4 and 14.7 depending on the temperature of the alternator. It has been fine for two years now, two years of very aggressive use. I doubt that you really have any problem at all