Why does my car battery keep dying?

Question

My car died on me on the way to work. I took it to a near by auto shop; they said it was the alternator, so I put one in then a day after I put in a new battery. Two days later my battery was died. How can this happen nothing in my car is on (I took out my CD player as well).

Answer 1

Now that you have a new barttery, and a new alternator, it is time to find out what your problem really is!

It could be as simple as a "draw" on the electrical system while your car is parked, - (but would have to be parked long enough to have too little power left to start the car), - in which case, - IF there was enough power left to get the car running, the alternator would charge the battery back up! So if started a number of times during the day, it would always start and run fine!

Here is how you check for "drain" on battery. Get a test light, and pull one terminal off the battery. Connect the test light between the battery, and the battery cable, (now it is the only link to the cars electrical system), - and it will light up whenever there is "power being used". The test light can be one you bought from the store, or just a bulb (any size) of proper voltage used for the car, -(just conect wires by soldering, -or maybe something with a bulb socket already can be used for the connections to battery and cable)! You can start disconnecting things, and pulling the fuses till you find out what is causing the car to "use power" when you are not using the car! Once you locate the culprit, you can leave it disconnected till you get around to finding out what the problem is (if it isn't essential to driving safety)! Note here that even having the door open causes the interior lights to burn, so the bulb will light ( so make each check with the doors all closed or the interior lights turned off (if possible)! Also if the light is very dim, ignore it, as the power draw isn't enough to cause problems (unless the car sits for a month!)


Next thing , - could be a problem with the charging system! My suggestion is to take to the place the battery came from, (or Wal Mart, - or most of the automotive parts houses), -- and have the charging system in the car checked out. If you have a ampmeter, - or "battery" level meter in the car, you can tell if the charging system is working (because the meter will read much higher than when not running). Next check to see that your "main supply" fuse (may say battery on fusebox),- is good. This will probably be 50 amps or bigger fuse! Also check wires that plug into the alternator, as one of them could be broken. With a test light (or voltmeter) you shold have power at the "A" terminal on the plug. The other one is for the "idiot light", - don't worry about what it may or may not read! I have seen the wire running from the alternator to the battery (with)"lose connections" on the terminals on either end quite often. So use a "jumper wire" (being farily heavy) connect one end to the alternator (under the connector terminal),- start the car, and then "arc" a connection to the (+) positive terminal of the battery. -- If you get sparks here, -you have a bad connection (or wire) going back to the battery to charge it!... Note that this will also bypass the big fuse I just mentioned above! Also with the car running, - you can "arc" a wire connected to the "big terminal" (on alternator where the power to battery goes out), -to the "F' terminal (one of the two on the plug in the side at the back (or on the side,- on the end), - if you have these two connected, the power is "bypassing the whole electrical system" Which means that none of the ignition system through the "ignition switch assembly is now required to get power to the field ("F") of the alternator to make it charge! It is also to be noted that if the car is idling, and you get the alternator charging, it will make kind of a "humming" sound and pull the engine rpms down just a llittle, - so you can tell if it charges when "arcing the wires" as described above! .. By the same token, it will get quieter, and the engine would speed up a little when the plug is pulled at the back, (since you are removing the "field power"!)

Answer 2

I had this a couple of years ago. There is something that is draining the battery while the car is parked. In my car it was the automatic radio antenna drive, though I first suspected the alarm. Another possibility was the central door locks.

Get the car in a really quiet spot and listen for any sounds it might be making while a charged battery is connected. Though some people might suggest a light remaining on in a glovebox or luggage compartment, these hardly use enough current to have much effect, but it's worth looking just the same.

Connect a voltmeter across the battery or an ammeter good for say 20 amps between a battery terminal and the disconnected negative lead. If you have not got an ammeter the current drain might be enough to light a low-watt 12 V bulb. Pull fuses until the current stops or the voltage rises a bit. Then you know where the problem might lie.

Answer 3

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Answer 4

Help!! I have a 99' Honda Civic. 75,000 original miles. When I first got the car at 68,000 miles I did a tune-up. 2 or 3 months ago I bought a new battery a few weeks later the battery was dead. I took it to my mechanic and he stated it could be the battery we purchased so I went ahead a purchased another battery. A month later, again the same thing. This time we put a new alternator and here we are again. I know the battery is new, alternator is new, what else can it be? I am not understanding and now I am just getting frustrated. Someone please help!

Answer 5

Take your car to an auto parts store and have them check the charging system. Most have a test unit and will do it for free. They will be able to check to see if there is something draining the battery, i.e. a short or accessory(won't be able to tell you where, but will be able to show the drain) , and check the battery itself. How old is the battery? A typical battery averages 2 - 3 years before it goes bad. Does it go out all at once? If so, this could be a bad cell or intermittent short between the plates(usually caused by sediment). Try these things and good luck!

Answer 6

This Site Might Help You.

RE:
Why does my car battery keep dying?
My car died on me on the way to work. I took it to a near by auto shop; they said it was the alternator, so I put one in then a day after I put in a new battery. Two days later my battery was died. How can this happen nothing in my car is on (I took out my CD player as well).

Answer 7

Faulty alternator not charging the battery (keeping it up),bad battery thats not holding a charge,slipping belt,bad wiring or a constant drain.You might not have needed either part to begin with,it might have been a vehicle problem.Many times parts are installed needlessly,as we only treat the symptoms and not the real problem.If you get a headache you take aspirin,but rarely is the real cause for the headache a concern.Yet the headaches come back.
I would check for charge output,and if its charging,have the battery load tested after its recharged (by a battery charger),if its good,then you have a drain.....or the charge isnt reaching the battery (bad wiring).

Answer 8

If you're sure the alternator and battery you had installed were both good, then you have a short, either in your wiring harness or your voltage regulator.

Next time, take your car to a reputable mechanic. You just spent big bucks on repairs that didn't fix the problem.

"Hit and Miss" is both an expensive and a time-consuming way to repair your car!

Good luck!

Answer 9

New Battery Reconditioning Course!

Answer 10

My car will run fine for months (4-9), start strongly and the battery will die after leaving it parked (with the lights off and doors closed.) At some point, I leave it parked for a day or two (after starting and running perfectly) and the battery dies the next time I try to start the car.