Twin Turbo Alternator

[BOCG]

My TT lost power while driving. I was able to get it home by connecting a battery charger to the battery. Noticed while taking home that charge was 11.2 volts. I am assuming this is a bad alternator? Is the alternator on a TT a stock c-4 alternator? Is there anything alse that could cause this? Any advice would be appreciated. Thanks.

 

[TAC]

It's just a standard C4 alternator. It may be that the battery is bad and/or the alternator. The alternator is pretty wimpy and when it goes out it can cause the battery to deplete itself over time if not caught quick enough. By the same token, if the battery went bad first, it causes the alternator to work overtime trying to keep up, causing the alternator to wear out. I've read many posts that advocate changing both alternator and battery on C4s when one or the other goes TU. My own TT had the same problem you describe and I managed to limp home. A test of the battery showed it wouldn't hold a charge and a check of the alternator showed it wasn't putting out proper voltage. I fixed both.

 

[BOCG]

TAC, Thanks for the quick reply. I think your advice makes sense as I do not know how old the battery is..will replace both. Thanks again.

 

[TurboLuigi]

I agree with TAC, it could be the result of one or the other and in most cases the bad battery will eventually kill the alternator. Over time I have replaced both on my car. As for wether to replace both at the same time, I'm not sure that I would just do that without testing first.

-Luigi
:cool

 

[*89x2*]

Here are some insightful links:

http://corvetteactioncenter.com/forums/showthread.php?t=32783&highlight=alternator

http://www.corvetteactioncenter.com/forums/showthread.php?t=88081&highlight=alternator


I hope this helps

 

[Peer81]

I don't agree with TAC on one thing. You only need the battery to start the engine. When the engine runs the alternator has to provice enough current to keep it running. If the Ah from the alternator is to low (wear) or to high electrical acc. like a big stereo the battery will help but within a few months will be killed to! But bottom line is that the alternator controlles 100% of the current when the engine is running, if it doesn't the first thing to fix is the alternator and if you wait to long the battery will go to.

Groeten Peter

 

[SurfnSun]

I don't agree with TAC on one thing. You only need the battery to start the engine. When the engine runs the alternator has to provice enough current to keep it running. If the Ah from the alternator is to low (wear) or to high electrical acc. like a big stereo the battery will help but within a few months will be killed to! But bottom line is that the alternator controlles 100% of the current when the engine is running, if it doesn't the first thing to fix is the alternator and if you wait to long the battery will go to.

Groeten Peter

Peter,

I believe TAC is correct. On the C4 cars if you disconnect the battery while the car is running it will die.

 

[Peer81]

Interesting to hear Josh!

If somebody knows why I would like to know because I think it should be possible to run any engine on the alternator only

Groeten Peter

 

[ET-VIPER]

A ALTERNATER NEEDS POWER TO PRODUCE VOLTAGE.ON THE OLD CARS THAT HAD A GENERATOR YOU GOOD CHANGE OUT BATTERYS AND THE CAR WOULD RUN.NEED TO BE AT FAST IDLE.

ALTERNATER NEEDS VOLTAGE TO PRODUCE A FIELD.
GENERATORS HAD MAGNETS TO PRODUCE THE FIELD.

STEVE

 

[SurfnSun]

I was under the impression that the emc still runs on the battery and the alternator maintains the battery while the car is running. The differences in output of the alternator would fry the ecm if it was wired directly.

I could be wrong but thats how it was explained to me if I recall correctly.

 

[TAC]

I don't agree with TAC on one thing. You only need the battery to start the engine. When the engine runs the alternator has to provice enough current to keep it running. If the Ah from the alternator is to low (wear) or to high electrical acc. like a big stereo the battery will help but within a few months will be killed to! But bottom line is that the alternator controlles 100% of the current when the engine is running, if it doesn't the first thing to fix is the alternator and if you wait to long the battery will go to.

Groeten Peter

I'm no electrical engineer but I know what happened to me. Halfway home one night I had almost all my dash lights come on and then started fuzzing in and out. The car barely would idle so I kept it going with the gas peda. I pulled into my garage and turned the engine off. I immediately tried to start it again but it was d-e-a-d dead. Barely got the clicking sound. I put in a new battery but still couldn't get decent voltage so I replaced that too. Life was good again. The shop I took the battery to said one cell was gone so the battery was definitely gone. Which came first I don't know.

 

[Brangeta]

I don't agree with TAC on one thing. You only need the battery to start the engine. When the engine runs the alternator has to provice enough current to keep it running. If the Ah from the alternator is to low (wear) or to high electrical acc. like a big stereo the battery will help but within a few months will be killed to! But bottom line is that the alternator controlles 100% of the current when the engine is running, if it doesn't the first thing to fix is the alternator and if you wait to long the battery will go to.

Groeten Peter

I agree with you. I don't understand why the battery would have anything to do with anything after ignition. The only way it seems the battery would have anything to do with the car dying (in my opinion) is if the battery was required to complete the circuit.

As always, I'd probably just unscrew the cables from the terminals, check for corrosion on the inside where they touch, and go from there.

 

[BOCG]

Thanks everyone for the advice. I bought a new alternator while in the US last week and it is in the shop this week for installation. Will make sure they check the battery and wiring to be sure. Thanks again.

 

[shopview]

The battery acts as a large capacitor for filtering and peak load handling...

 

[TurboLuigi]

I believe that real old cars with alternators should have the ability to run at idle with the battery disconnected. My first car was a 1969 Chevy Impala and I could swear that I could swap the battery with the car stilll running.

Actually, this weekend I can try a test on my 1956 Thunderbird which has an alternator (took out the old unreliable generator).

However, cars that are EFI and computer controlled will die at idle. I remember when the Alternator died once on my Twin Turbo on my way home that if I eased up off the accelerator, the dash lights would dim and it felt as if the car was going to turn off. Of course, it eventually did because of traffic signals and stop signs, right around the corner from the house.

There are too many systems on todays cars, even from the 80's to operate without an alternator or battery.

-Luigi
:cool