Just noticed my voltage seems a bit lower than usual, however it's a very hot day here in Phoenix and I had a/c on. Is 13-13.4 normal or low for these conditions?

 

I had to replace mine, got a 170A and it reads 14.6 V allways.

 

Just had my GS out yesterday for a quick run to move oils around and such, pretty warm 111'. HWY drive the volts were at 13.9-14 V, hope that helps because I don't know much
NSF

 

Mine always reads just a touch over 14.

 

I only pay enough attention to notice that the voltage varies considerably; depending on RPM, temperature, battery charge, electrical load, etc.

Sorry I can't be more specific.

 

I get low 13s in traffic.

 

Like many things here on the forum, more is not necessarily better. As long as the voltage stays above 13.2, all is fine. And just because it stays at 13.2 does not mean that the alternator is working hard to keep it there and can't go any higher. The voltage signal to the alternator is controlled by the computer. If it is keeping the system at 13.2, that is because the computer is telling it to. Same goes for 14.4. A higher voltage is not telling you anything about the capacity of the system.

 

Read about 170A Alts here
https://www.corvetteforum.com/forums...ternators.html

Forum vendor is on site.

 

Thx cclive - i was gonna charge the batt but after reading your excellent response I'm a happy camper yet again.

 

My voltage drops to 13.7-9 when hot outside and I'm running ac. All other times runs at 14.2. Battery is going on 4 years old and will likely be changed out this winter. OEM Delco stock battery.

 

thats what im wondering. when i first got my car..(used) my battery voltage was going crazy. turns out alternator gave out. now with a new one, i always keep an on it. i live in south texas, and temps around here are 98-104F. i noticed when a/c is on, sometimes, as soon as the high fan kicks in, it drops to 13.1- 13.7v in the city or stopped. As soon as the car is rolling or expressway.. 14.1 - 14.4v im basically traumatized about it.

then doing some searching...my car came with a new 475 cca battery that the dealer put > and found out the corvettes minimal cca required was 675 if im correct. me thinking that was the issue, i got myself a yellow optima battery that is 750cca. it helped but does the same thing.

I know when im at a stop and the voltage drops..the a/c isnt cooler as it would be when the car is rolling. Makes sense that its a load of course.

i also noticed, but sometimes...when i first turn on the car, and as soon as i put it in reverse to get it out of my garage, it drops automatically to 13.1-13.3. then goes back to 14 when i drive.

so is this normal??

 

Yes, it's fine. At idle speeds, the A/C compressor is not being spun fast, so it won't cool as much....same with the alternator...it won't produce as much current at idle. You're fine, don't worry.

The fans, seat heaters and inside ventilation fan are some of the highest current users in the car...rear window defroster also. When these are on, they will pull the system voltage down, especially at idle when the alternator is at a disadvantage. Normal.

 

so is there a voltage BELOW which is worrisome, like perhaps 12 V?

 

111 is "pretty warm"?? Of course, your humidity was probably around 3% with a dewpoint in the 50s. We hit 100 yesterday and it was humid as hell. 'Bout died on the golf course. Played in Yuma one time when the temp was 107, as I recall, but it felt fairly comfortable until I grabbed an iron out of the bag.

I'm thinking voltages in the low to mid 13s with the AC going and the car idling is fine, but I'm far from an expert on electrical matters. I rarely look at the volt meter.

 

Mine has dipped below 13v in traffic, at night, 105ş with all lights and ac on. I don't like to see that but nothing bad has ever happened.

 

If it stays at 12 to 13 V all the time you have a problem. Not enough V to run the car and charge the battery so eventually the battery will go dead. That is what mine did. OEM Alts do not like to be over reved.

A constant V supply will make things run better and smoother at idle. Just checked mine, ac on full at idle 14.5 V.

 

That is true if the Alt is capable of producing more voltage at idle. OEM struggles at idle and is maxed out till revs increase. Bullet tech can produce 14.6 V at idle so it can supply the voltage requested.

 

Ha-Ha Dawg, here you learn to not grab anything laying in the sun
I had a photo of my outside thermo (in the back patio) pegged at 120' couple of years ago in July, whew, hot. Warmest I have seen was 127 in July again about 15 years ago, and that's just too dammn hot.
I think of the poor soldiers over there in that hell hole at those temps, gotta be MISERY
NSF PS August is when we get humid, SUCKS

 

THis is why there are all these Corvette electrical gremlins....crappy GM alternator.
I got this and I am pegged at 14.6 all the time...plus they come in black!
https://www.corvetteforum.com/forums...w-pricing.html

 

With a multimeter in hand set to 20v DC,

Start the car with the hood open.

Put the ground probe of the multimeter to the body of the alternator, and on the back of the alternator under the rubber boot, put the positive probe to the threaded part of the terminal (not to the cable part). You should have 14.6 volts if the alternator is good.

Now put the probes to the battery lead terminals and check voltage. The voltage should be 14.5 volts (about .1 voltage less than the alternator direct reading since you will loose this small voltage in the wiring/motor aluminum between the positive and negative paths between the two).

In the car, kick the DIC over to voltage, and the reading should be about .3 volts less than the battery reading (again, loss from the wiring/devices from the battery to the gauge cluster and if the altinator is putting out 14.6, then the DCI should be reading 14.2~14.3 .

So if you have 14.6 at the alternator terminal to the alternator body direct, but the voltage is dropping way down after that, it not a alternator problem, but a wiring connection problem instead.

The positive red cable off the back of the alternator terminal bolts to the starter on one terminal, goes through a bond bar in the starter, then to another red wire that goes back up to the battery, the a smaller red wire that goes the fuse block terminal.

On the ground side, the large negative black wire bolts to the engine block just above the starter, and another black negative wire bolts to the chassis just below the battery.

So all these wires, and there connection need to be pulled, the wire connectors cleaned, the bolting terminals cleaned, then use dielectric grease on the connecting parts before reinstalling the wires to slow them down from corroding/oxidizing again.

And as stupid as it may sound, I have seen problem of even just a bad connection from the back of the alternator terminal to the first wiring contact that has caused low voltage problems.

Note, if your DIC is reading 14.6 at idle, then the alternator is pushing at least 15.1 volts at idle to the battery instead. I bring this up, since if you are pushing more than 15.1 volts to the battery (say at mid revs and higher), then you are over voltage's the battery when it's being charged, and will shorten the life of the battery instead as you are boiling it. I bring this up for the guys that state that their DIC are holding fast at 14.6V, and may want to pull voltage on the battery when the engine is rev'd up to make sure that the battery is not getting more than 15.1 volts at any given time.