Installed 200 amp alternator

[rickv2009]

Hello all! I have a 96 exp. 4.0l. The alternator was bad. I replaced it with a 200 amp one because it was cheaper than what I could get locally. Before the new alt the batter guage was at the L line and would steadily go down unless I charged it overnight, every other day.

After installing the new alternator the guage was in the middle or just above middle. BTW, the alternator fit perfectly. I am now having a problem where when I rev the engine the battery light comes on and the guage goes down. If I let off the gas slightly the battery light goes off and the guage goes back up.

Any help would be appreciated. I am thinking I need to upgrade the wires?

I checked out the thread that shows the wire and stuff but I need to know exactly where to run the wire and which wires I need to replace.

thanks in advance.

rick

 

[my98nnj]

Make sure the belt isn't slipping or glazed over. Have you put a volt meter on the system to see exactly what's happening? Is the voltage dropping from ~14 to battery level?
Why did you put the larger unit in? Are you running large audio equipment or excessive lighting and other electrical equipment?
If the belt is ok and the unit is indeed spinning at engine speeds and your still seeing the drop in voltage as you rev it up, return or exchange it for another one.

 

[rickv2009]

200 amp alternator

No particular reason for the higher amps. I found this Alt for a cheaper price than I could get locally.

I have not put a volt meter on it yet. I put a battery checker(just has lights to indicate voltage) and it lights up all the way. Before I replaced it the battery checker would not go above the first light.

Belts are not slipping at all.

It does not happen gradually. It is almost like it looses the ground. Maybe the stock wiring cannot handle the higher current?

I do plan on running the heavier wire.

 

[my98nnj]

No particular reason for the higher amps. ..... Maybe the stock wiring cannot handle the higher current?

I do plan on running the heavier wire.

You don't need any heavier wire if you're not pulling any additional load.

The alternator doesn't output any more then you draw from it. So if you don't have any additional electronics, or load on your electrical system, the alternator isn't producing anything excessive or more then a standard unit would have.

 

[rickv2009]

Upgraded alternator

So more than likely I just need to change the wiring because it is worn out? Should I put in a heavier guage wire?

 

[rickv2009]

200 amp alternator

OK,

I am still getting the guage dropping and battery light coming on at high RPMs. I checked the battery connections and the hot side was loose. I reconnected both by cutting them and reconnecting. After I verified the connections were good I revved it again and the guage dropped and the battery light came on again. At about 3000 RPMs or so.

What else can I check?

Rick

 

[gonenuke]

Might want to check the battery again, because it might not have been getting charged so long. It has a dead cell. Use a volt meter this time. Just a thought.

 

[Midwest Dually]

Indeed. If it is a serviceable battery, you may want to check the fluids too!

 

[DUNE RCR]

Exchange your alternator with a new one. It sounds like the regulator in yours now is defective.

 

[DUNE RCR]

I know with mine (200 amp alt) that if I idle for a long period of time that my battery will start to decrease in charge, but that is because of the design of a higher amp alternator. At idle they don't put out enough amperage to charge but at a higher rpm it puts out what you need, this is why I believe yours is defective. I run multiple accessory lights and a custom stereo system so I needed to get my 200 amp alt, seeing I blew through 4 in less than a year.

 

[rickv2009]

I checked the output with a gauge that just have lights on it. It has lights for not running and running. Red, amber green.

Red for too low, amber for low and green for good.

I connected it before I turned it on and it went to the green.

I started it up and it was to green. I kept it connected and revved the engine and the lights went down to red and the battery light came on and the console gauge went down.

Is there a way to test the Voltage regulator or for sure test the alternator?

I am going to take it to oreilly auto after work.

Rick

 

[rickv2009]

200 amp alternator

I took the 200 amp alt to Oreilly's and it passed all tests. Just for grins I had them test the old on and it was bad. They also tested the battery and charging system and it was fine except when I revved the engine.

I checked the ground wires and they were fine. I was getting a good ground from the battery to the engine(it is connected to a started mounting bolt.) I checked the battery to chassis ground and it was good also.

I am not sure what else to check. Could it be the system cannot handle the 200 amp alt? Should I do the big three? (new, bigger wires from alt to battery, battery to chassis, battery to engine?

Are the fuses I should check? Relays?

It is very frustrating.

Rick

 

[DUNE RCR]

I would take it to another place and have it tested. Try to find a place that specializes in alternators and starters and have them test it. Something isn't right with you alternator if it isn't charging at a higher rpm.

 

[KillerKidd42]

I was going to recommend the big three. Even if its not the solution its still a good idea.

 

[SoNic67]

Probably the regulator board inside the alternator cannot handle the higher rpm's.
Replace the alternator while in warranty...

 

[colintrax]

This is a problem with the alt, as someone else already said the alt won't push more amps than its being asked to make. Unless you got a ton of lights and a system, theres no reason for the "big 3"

 

[budwich]

I took the 200 amp alt to Oreilly's and it passed all tests. Just for grins I had them test the old on and it was bad. They also tested the battery and charging system and it was fine except when I revved the engine.

I checked the ground wires and they were fine. I was getting a good ground from the battery to the engine(it is connected to a started mounting bolt.) I checked the battery to chassis ground and it was good also.

I am not sure what else to check. Could it be the system cannot handle the 200 amp alt? Should I do the big three? (new, bigger wires from alt to battery, battery to chassis, battery to engine?

Are the fuses I should check? Relays?

It is very frustrating.

Rick

Yes but how did they actually test your alternator (ie. in vehicle, bench, live, static).... depending on what / how they tested, they didn't actually test it... all ...

 

[rickv2009]

200 amp alternator

They bench tested it and also in the vehicle. They hooked up their tester on the battery and I revved the engine. The battery light came on and the gauge went down.

When they bench tested it there was no problem. It passed all checks.


BTW, I hooked up my little tester to the alternator and revved the engine and the lights went down. It is very odd. Shouldn't the alternator still be outputting the correct voltage even if the wiring is not good?

Very weird.

Any help is appreciated.
rick

 

[DUNE RCR]

Like everyone has said, just replace it while it is still under warranty. There is something wrong with the voltage regulator.

 

[my98nnj]

They bench tested it and also in the vehicle. They hooked up their tester on the battery and I revved the engine. The battery light came on and the gauge went down.

When they bench tested it there was no problem. It passed all checks.
rick

Seems common sense is missing at the auto parts store.
I'm sure the bench test doesn't involve a 3000+rpm spin, so it makes sense that the bench test passes. But where the lack of common sense happens is when they actually see it fail in your vehicle when the engine/alternator speed is increased.

It's defective, make them replace it.