What is the proper reading? Right now, with the engine running my ammeter is reading +20, I believe. Isn't that too much?

 

Yes, That to much, you can over charge the battery. Someone will correct me if I'm wrong but I belive it should be around 13-14 volts.

You should check your regulator.

 

The regulator at the alternator? I would think if that is bad it would read less as the alt. isn't working. Or do you mean something else? Also, should I not be driving it? I just realized it when I got to work.

 

Yes the alternator regulator, it could be stuck closed, this would over charge the battry, which could blow or cause other electical damage.

 

Are you talking about an ammeter or a volt meter ??? A volt meter should read 13 - 14 volts...................... but I don't know what an ammeter is supposed to read to be functioning normally !

 

The ammeter is reading amps-load. It shouldn't read anything- thats a I think . I seem to remember when a high load is put on it goes up but should return to zero. Like a cold winter morning with everything on, it reads high. If the battery is good it should go down.

If fragmented brain cell serves its usually a bad battery.

A bad battery can pass a voltage test. To be sure do the turkey baster specific gravity test, this shows whether its good or not. New batteries can be bad also.

If your running something insane like an electric fan maybe its normal. With everything off there isn't much amp drain.

 

Whatever the gauge on the instrument cluster is.

 

Early sharks use an ammeter...later use a volt-meter. The charging current just after start-up will be around 40 amps, then fairly quickly drop to 20 amps. After 10 min, it will stabilize at around 5 amps...that is the nominal trickle charge needed to keep battery at peak. Now when driving with a/c and headlights on, it will show - amps(discharge ) if at idle rpm......

 

You first need to figure out if you have an ammeter or a volt meter. They measure two very different quantities.

An ammeter should read positive right after you start your engine. The ammeter measures current and the positive reading indicates that the altenator is putting lost charge (from turning the starter) back into your battery. As you drive, the ammeter should drop to near zero (but still slightly positive, in most cases) as the battery returns to normal charge. If the ammeter reads negative, then your car is drawing current from the battery in order to keep up with the various electrial loads you have turned on (or the altenator is not working). In this case, the battery will eventually go dead.

Hank

 

So a little bit to the right of the zero mark is normal for the ammeter? I've been meaning to ask this question myself. Right after start-up, mine goes to around +20, then comes down to around 5 and stays there while the car is running. This isn't too much?

 

Nope

 

It's easy to tell if you have an amp meter. With the car off turn on the lights the gage will show a noticable discharge. A volt meter only works with the ingition on. If you don't drive your car much it will take some time to get the amp gage down to +5 amps, if your battery is well charged, you should be about one needle width to the right of where it sits with the ignition and the lights, heater blower, and wipers off when running down the road.

 

Sorry, My bad. I just assumed that he was talking about the volts, not thinking about what he said, "ammeter".

 

Ammeter shows load. Since I wired my fans to my starters battery connection, my ammeter will jump to 40 (20 at idle) when the fans are running. It is a nice double check for me to then sneak a peek at the temp gage.

 

With engine not running (ie. the alternator not being driven by the engine) a volt meter will show a negetive or a discharge when you turn on your lights or honk your horn or play radio or ANYTHING which uses battery power. regardless of wheather or not your voltage regulator is good or not. An ampmeter will not indicate anything one way or another.

With your engine running an ampmeter will show a charge unless your battery is FULLY charged. If you turn your lights on your meter will show an even greater charge rate. Like others have said, you will see a slight charge even with a fully charged battery with your engine running...after all, it does take some electricy to fire those sparkplugs.

Be sure and keep an eye on your battery water, even the so-called maintenance free batteries. Keep them from getting too low. Those two flat covers on top will easly pop off with a screwdriver to expose three cells each. A charging system which charges at too great a rate will 'boil' the warer out. There are some completely sealed batteries but most of us don't have them.

BE CAREFUL AROUND BATTERIES.....don't get any acid on you or you're interior and wash your hands when you are thru. Just a slight amount of acid will ruin your day.

 

Early C3's had ammeters and they should read barely on the + side when the car is running normally. It will show a large + draw when starting and shortly thereafter. Once running and the alternator charging properly there should be a slight + reading. That is normal. If anything else the system needs to be checked starting with the alternator.

 

And if you have a near dead battery and a new 105A alternator, the ammeter will peg high when you start the car, then stick, because now it is broken. Don't ask me how I know.

 

Everyone else got it right. No, the voltmeter doesn't have a negative value on the scale but the ammeter does. And the negative side of ammeter indicates current discharge while positive side shows current recharge to batt. So a large load like short to ground would be a neg- ammeter indication and a hi charge rate from the alt would be pos+. That pos+ and neg- show polarity and current flow direction.
So if u show a constant +20 indication something is wrong with the batt or the alt internal reg. Ammeter should show temporary hi pos+ after start up and slowly return to mid-scale or close to zero.
Since u post u have pos+ 20 and most voltmeter scales only go to 18v my money is on u have an ammeter. Also voltmeter scales in cars have only a pos+ range usually like 6v to 18v.
BTW my vette is a '74 also and has the ammeter.

Well those are good precautions when handling batts and acids. BTW i got so dissapointed with the condition of my batt compartment i switched to the red-top Optima - and won't look back now. cardo0

 

A charge of the battery after you start your car will be read on the ammmeter. +20 amps draw is not out of the ordinary. As has been said above if it stays up after a few minutes of driving then something is wrong with the charging system. I found that when mine reads high after starting and stays that what a good cleaning of the battery terminals and major grounds (engine block, battery to frame etc.) is in order. Thats where I'd start if your current draw stays high a few minutes after starting.

 

Stereo on, engine not running, small (-) draw. When the car is warmed up and underway, the needle is just to the right of the mid-point: small (+) charge.