Alternator issues?

[Kelleyj1837]

I noticed my battery light came one today. Took it to school put a vat machine on it when it was running it had 12.4Volts. I put the amp clamp on and got like 4 amps output. So knew the alternator was shot. went to the auto parts store and got a new one also a voltage regulator located on the passenger side finder. I put the vat machine back on at idle and got 13.6 running at idle, and like 60amps. So I figured every thing was good then on the way home the voltage meter in the cluster started to flicker from like 13-14Volts. Just back and forth if I turned on the heater on high it would stop and go to normal. So I guess my question is should that voltage meter in the dash move like that??

 

[thx997303]

It's basically a dummy light if it's anything like the oil pressure and water temp gauges. Mine fluctuates quite a bit with a good alternator. They're notorious for bad grounds.

 

[Kelleyj1837]

Bad grounds on the gauges or the alternator. I have a wire on my alternator that goes right to the negative post.

 

[OLDBULL8]

I think your first alternator was OK, probably changing the regulator solved the charging problem. How good are your batteries, only way to test them is with a hydrometer for specfic gravity, check each cell on both batteries.

 

[fordf350man]

bad connectons is deffinetly something to look for as said above, also remember that just because its a new alternator doesnt mean its good and there sohould be a tag or something on the alternator that has the spec for its amperage output then you know what it should be, im not to sure on what you have or on these old diesels that most of us have, but 60 amps seems low to what i have seen,

 

[Kelleyj1837]

I got the alternator tested and it failed. also the bearings where screaming. Both battery's load tested good with good voltage. Working fine.

 

[Kelleyj1837]

I do know that a alternator does turn on and off rapidly. But that gage should not pick up on that.

 

[icanfixall]

Sounds like a suspect alternater. BTW that amperage is too low for our trucks.

 

[OLDBULL8]

Sounds like a suspect alternater. BTW that amperage is too low for our trucks.

He's getting 13.6 VDC and 60 amps out at idle speed. I think that's pretty darn good. Full output is at 2K RPM on most alternators.

 

[icanfixall]

Bill at idle my alternater puts out 14.2 volts. Now my alternater probably is a better built unit but thats what my comment about low 60 amp output was posted. I know we can run a 200 amp alternater on these engines be it serpentine or v belt systems. I want one of those but really don't need it. Its kinda why fix it when its not broken thing. When I bought the one on my rig now I paid around $180.00 for it on ebay from a builder that sold it as a 200 amp unit. Took it to my favorite mom and pop shop to test and they told me it was a 100 amp unit. Not 200 amps... I was not happy but they told me what to look for in the 200 amp units... Next time...

 

[OLDBULL8]

Gary; I won't argue with that, but the pulley size on the alternator does make a difference on idle output. Voltage out also depends on what the batteries need for fully charge.

Kelly1837 is coming over today, we'll ckeck it out. Found out he lives here in Delphos.

 

[Pull-n-TugTx]

Im here to listen in and would like to know what y'all find out. My voltage gauge jumps around a lot. Had one battery go out on me yesterday, both new back in Feb. Alternator tested "good", but wondering why primary battery died so soon. Possibly looking to upgrade alternator.

Sitting in the corner quietly.

 

[icanfixall]

We do not have a primary or secondary battery. They are connected in parralel and we have 12 volts but double the amps.. Thats why it important to know what wires are electrically hot at al times. The glow plug controller. The alternater and the starter is hot at all times. Ground any of those wires and see the fireworks happen. Ground it with the ring on your finger and you nearly loose the finger..

 

[Pull-n-TugTx]

Yes. By Primary I meant the battery that has alt, starter etc. wired directly to it.

Not sure why this battery would die in 6 months and the other have no effect. Is it possible that I need to check grounds and maybe put some of the acc. on the other other battery. I ocasinally have my lights flicker, sometimes the gauge reads normal at idle, bounces at in higher rpm. Sometimes it sits high, and then bounces like crazy for a couple of minutes and then sits in the normal range. It happens at all different times, i.e. lights on/off hot/cold 1.500/2100rpms.

Not to highjack the post just trying to get some perspective, and dont wanna have it burn up on me or leave me in the dark.

 

[OLDBULL8]

Don't make a difference where you connect the wires, the Voltage/Current is from both batteries. Any battery can Die at any time. You could have ten batteries connected in parralell, but they would/will act as a single battery.