No such thing. If you have a new battery, and the alternator's testing fine then there's obviously something draining the battery.
You'll need a multimeter for this. First off, once started, test the battery voltage at idle. Then increase RPM to about 2000. The idle reading could be as low as 10 Volt(since you just put a massive drain on the battery but should pick up with RPM to aboout 13 Volt at least. It could even go up to 14 Volt.
If that is fine, shut down. Disconnect the neg pole on the battery. Switch your multimetre to Amps(You may have to move one of the meter wires to a current measuring connection on the meter.) Connect the leads between the neg of the battery and the cable that came off it. A reading any larger than 0.5 amps (500mA) could mean trouble. First thing I always check for is trunk and glove compartment lights. They may not be turning off with the lid closed. Next is aftermarket amplifiers. If incorrectly installed it does not shut down and drains the battery in no time at all.
There is no magic box of tricks controlling the alternator output other than its regulator which is part of the alternator. With the engine running the alternator supplies power directly to the battery (and the rest of the electrical system) controlled ONLY by the regulator. The alternator has 3 connections. a Negative(earth) which is through the alternator casing to the engine, so no wire there. A positive via a thick red cable to the battery positive. A "indicate" connection which in effect only shows that the alternator is supplying power.
The alternator HAS to supply enough power to sustain all the electrical components on the vehicle AND charge the battery at the same time. If the car dies while driving and the battery is flat then the alternator is obviously not doing its job.
Do you have a multimeter? Did you test the voltage at idle and at 2000 RPM as I suggested? If you dont have a multimeter, Jumpstart the car. Rev it a little to ensure that the alternator comes on. When idling, disconnect the neg of the battery.(This is not recommended, since some alternators, especially older and generic designs are not able to cope with the spike in voltage caused by disconnecting its load) If the engine dies, the alternator is duff and needs to be repaired whether you've already replaced it or not, either that or it is installed incorrectly.
It should have 2 wires connected.
Also make sure the engine is properly earthed. There should be a braided bare metal wire/strip running from the gearbox to the body of the vehicle. On some models it is a thick black cable. These vehicles differ from region to region. (Earthing can be tested by connecting your multimeter between the battery positive and the alternator casing with the engine running. Measuring even 1 volt at this point is too much.A thick red cable connected to B+ on the back of the alternator . This wire routes directly to the battery via a cable that leads to the starter as well. It should always be at 12V(Battery voltage) whether the vehicle is on or not.
A thin wire which goes to the dash indicator. When you switch the ignition to "on" the charge light in the dash should glow (Indicated by a symbol that looks like a battery) If it does not glow you either have a blown fuse, the wire is broken between the dash and the alternator somewhere or the alternator is faulty. This light should be off when the engine is running.
Another obvious thing to check is that the battery positive cable is not chafed and shorting out somewhere in the engine compartment. Although it would be pretty obvious if it were because it would be throwing a lot of sparks.
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we have had to replace alternator several times and the car even dies when we drive down the road .we cant get the engine fan to turn on but if we jump it the fan runs thats why we replaced everything but the car will not stay running. it will work for a day then the same problem.what else can the problem be?
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