ALT gauge question

[JoeGrapes]

Why does my ALT gauge always read half way on the C side when I'm driving? Shouldn't it pretty much be centered? My volt gauge reads 14.5 volts. What will cause it to read that way?

[TelisSE440]

It can either be two things, the battery was undercharged, so it is charging a lot (not likely as you said it always does that), or there is a device (aftermarket) that draws a lot of current, like electric fans, electric water- fuel pump, or all electric devices actuated simultaneously, also electrical shorts draw a lot of current,  hope I helped...

[roadman5312]

If talking about the factory gauge, it's an ammeter. Check on the back of it, the connections. See if they look burned, or have been hot. If volts are 14.5 your good, but the factory ammeters caused lots of problems. Best to bypass. 

                                                                               

[JoeGrapes]

The only extra draw I have is the EFI ECU and fuel pump. Maybe my battery is just not holding as much of a charge as it should. Or my voltage regulator is malfunctioning. Can anyone tell me what amps the gauge is calibrated to? If the needle is all the way to either discharge or charge how many amps is it reading? 

[acudadude]

Please read this might help
http://www.madelectrical.com/electricaltech/amp-gauges.shtml

[JoeGrapes]

Really good read, thanks

[67vertman]

I run an EFI and electric fuel pump like you.  And my ammeter used to read the same way.  I did the ammeter bypass, but haven't upgraded to an Alt meter yet. I haven't found one that looks stock as of yet. 

The ECU and fuel pump draw a lot of amps.

[brads70]

I found out the hard way that the stock alternator is not capable of providing amperage when you start adding on non stock upgrades. I suspect either your alternator or battery is on the way out, or the alternator can't keep up with demand and you are slowly running down the battery. 

This might be useful when calculating your required amperage?
http://www.qualitypowerauto.com/pages/AmperageLoadCalculator.php

[67vertman]

I should have also stated, I am running a 100 amp Alt now.  As Brad said, those extra add ons use a lot of Amprage.

[JoeGrapes]

I can see the battery being on the way out but if my alternator can't keep up wouldn't the ammeter be reading discharge since the battery would be adding extra juice to make up for the differance? I replaced the alternator years ago but I don't remember what amp alternator I have. I probably should get a 100 amp unit.