After market External voltage regulator increases with engine rpms. Why?

[DRocha]

Need help why voltage spikes when rpm increases

 

[62Blazer]

What is it "spiking" to? It's typical for the voltage to fluctuate some with engine RPM. That is because the total amperage output of an alternator increases withe RPM. This will cause the voltage to increase some as the engine RPM increases. I'm not saying it should spike real high, but I wouldn't be surprised to see mid-14 volts.

 

[DRocha]

I understand. Guage goes all the way to 3/4 when accelerating. At idle its at half way mark. Im going to look at the ground wire from regulator to alternator

 

[MrBonez]

You can also put the battery on a slow charge overnight and see if the behaviour changes.
A battery that's weak can cause your charging system to work harder because it's trying to do it's job of charging the battery and the gauge is just showing it to you.

Give it a shot, you might discover a real problem you need to deal with.

 

[Daw14]

How about using a vom and getting some numbers , instead of just guessing where the needle points .

 

[DRocha]

Yes. I will check it out with a meter. Thank u.

 

[MrBonez]

Just something to think about:
If you're in the habit of making alot of short trips - Under 5 miles one-way each time you shut it down and then start it again it could be the battery is slowly dying because between each start of the engine it never fully recovers the charge expended from starting it - In short, the battery is dying by degrees if that's the case.

You have to let one run on occasion long enough to fully recover the charge expended from starting it.
Bear in mind each time you start it, that's another portion of charge gone and you normally cut it off when you get there and restart it to head back. Putting it on an slow overnight charge, like once a week if you do that will keep it from drawing the battery down too low over time, leading to things like starters going out (Burning up) and batteries going bad in general because they were in a state of deep discharge which can damage a battery.

Check your voltages and so on, then if it's charging normally (Within it's expected voltage range) that's something to think about if you're always going to the corner store just down the street and not much else aside from that.

 

[turkeybird56]

Just something to think about:
If you're in the habit of making alot of short trips - Under 5 miles one-way each time you shut it down and then start it again it could be the battery is slowly dying because between each start of the engine it never fully recovers the charge expended from starting it - In short, the battery is dying by degrees if that's the case.

You have to let one run on occasion long enough to fully recover the charge expended from starting it.
Bear in mind each time you start it, that's another portion of charge gone and you normally cut it off when you get there and restart it to head back. Putting it on an slow overnight charge, like once a week if you do that will keep it from drawing the battery down too low over time, leading to things like starters going out (Burning up) and batteries going bad in general because they were in a state of deep discharge which can damage a battery.

Check your voltages and so on, then if it's charging normally (Within it's expected voltage range) that's something to think about if you're always going to the corner store just down the street and not much else aside from that.

My RAM is basically GG, so battery will charge at 14.5 initially, then roll down to about 14.2 if I do a lot of driving, and even sometimes drop to 14.0 since the battery not need a big charge. But if OP, all U do is GG runs, short runs, U need to either run it a long way once in a while or put a battery minder/tender on it, or all the electronics on these rolling PC's will pull your battery below the threshold needed to start truck. Remember, OP, even off, there are modules in your truck that are still "ON" pulling voltage.

 

[62Blazer]

The other question is why did you need to replace the regulator to begin with? That might answer some of the above questions about the battery maybe being low.

Also as asked above, I would get some actual voltage numbers versus just saying it's "3/4 the way up the gauge". Honestly think there is a good chance you are chasing something that really isn't a problem.

 

[turkeybird56]

The other question is why did you need to replace the regulator to begin with? That might answer some of the above questions about the battery maybe being low.

Also as asked above, I would get some actual voltage numbers versus just saying it's "3/4 the way up the gauge". Honestly think there is a good chance you are chasing something that really isn't a problem.

Yeah, was trying to figure out why an external V/R? Trying to work around a failing V/R in alternator? Maybe installed a secondary battery to run optional stuff? Who knows.

 

[MrBonez]

The other question is why did you need to replace the regulator to begin with? That might answer some of the above questions about the battery maybe being low.

Also as asked above, I would get some actual voltage numbers versus just saying it's "3/4 the way up the gauge". Honestly think there is a good chance you are chasing something that really isn't a problem.

That was the thought I had about it, the OP can check how it's charging and go from there.

If possible I'd also check the electrolyte level in the battery to be sure it doesn't have a cell that's dry/low on electrolyte, that can cause a bad cell to occur and it's normally seen on the battery side towards the engine because it's a source of heat.

Heat from the engine to one side/end of the battery will warm up that part of the battery vs the rest, making the cell(s) on that side of it dry out faster due to simple, natural evaporation from it always being warmer than the other cells under heat soak and engine operation conditions.
Even if it's mounting/placement has one side with all cells more or less facing the engine on that side of it, the ones closest to the engine can become dry(er) compared to the others in the battery over time.

Remember, charging a battery in itself can make a cell(s) go dry too (Literally boil itself dry) and if the charging system is always working hard to charge it you might see evidence of that going on when you check it, that combined with the above can cause early death of a battery if it's electrolyte isn't checked every-so-often.

One sign you might have a cell going bad is when you look down into the cell and it's electrolyte looks murky/dirty with other cells looking clear/clean.

If that's the case then it could be inducing the charging system to overcharge the battery by the cell's resistance to charge, accelerating the process of battery death.

Guys I'm saying all this because years ago when I was working on battery powered industrial equipment (Forklifts and so on), I had to attend training classes and took a few of those classes taught by a rep from Exide.

You'd be suprised at the ways batteries can go bad and in turn affect other things too.