Low and Swinging Voltage

[Rchab]

Hello everyone!

So ever since I had to replace my original alternator back in August I have noticed that whenever I'm driving, my voltage constantly fluctuates. At idle it's around 11 or so volts depending on what I have turned on. I have an electric water pump and electric fans, as well as the headlight and all of the other lighting. When driving it's more 12.5 to 13 volts, again this differs with whatever I have turned on at the time so it could dip below that as well. Is this something to do with the new alternator not putting out enough juice? I have a remanned 55 amp alt in it now. The original alternator didn't have this problem as well, kept me above 12.5 the whole time if I remember right, at least enough for me to not worry about it. That being said I have yet to test the voltage coming out of the new alternator while it's running.

 

[Jerry Hall]

If you don't have 13.7-14.2 volts coming directly out of the alternator, get another one. Test with no accessories on.
I have never ran a voltmeter, but it's not uncommon at idle for an amp gauge to show discharge with accessories on.

 

[Rchab]

If you don't have 13.7-14.2 volts coming directly out of the alternator, get another one. Test with no accessories on.
I have never ran a voltmeter, but it's not uncommon at idle for an amp gauge to show discharge with accessories on.

I'll do that later tonight after work and I'll have to keep the water pump on but that'll be it. I wish I could find it again but I read somewhere that when the alternators get remanned the field terminal could get wound to a different connector. Is this a common thing and could be the problem? Right now I'm connected to the same connector as the original alternator

 

[Rchab]

Okay so I've done all the testing I can tonight, the battery had a shorted cell so I started by replacing that. From there I tested the system and here's what I got.

*at idle, alt is pushing out 15/16 volts with my volt meter reading just under 12
*at idle, the green wire connecting to the VR reads between 12 and 13
*at idle, testing the terminals on the battery, volts were dropping from 12.5 on down

This was all with only my water pump pulling extra juice. I was also reading that there are two different types of alternators that went in the chargers, one for points ignition and the other for electronic ignition. It looks like I may have the one for electronic even though I have points. Could this be causing a problem? I attached a screenshot of the two, currently I have the alt on the right.

 

[Rchab]

I did some road testing while going to the gym and here's what I found.
*Before I left I had 14/15V coming off the alternator's battery terminal.
*Both ends of the green wire at the alt and VR read 10-11V.
*Ign. terminal on VR read 12ish.
*I had between 12 and 13 through the whole drive
*Battery draining a little at stoplights
*every accessory (water pump, fans, lights) would change the voltage both turning on and off
*while going down the road I turned everything off briefly and ammeter bounced more towards 0 and volt meter read roughly 13, then dipped and ammeter went back to pegged once the water pump came back on.

Is this an alternator problem? Like not being enough amps so not being able to handle the pull everything is pulling on it?