my car battery keeps draining, its new, and the altenator is good, what can be making the battery drain?

Question

my car battery keeps draining, its new, and the altenator is good, what can be making the battery drain?

Answer 1

I'm a little unclear on how it is you know the Alternator is good, but lets assume it is. It's really not that hard to find a drain. The required tool is pretty cheap and the basic techniques are actually pretty simple, although it can be a little time consuming. Most cars have some items that take a little electricity while the car is turned off. But not enough to drain the battery unless it sits for a long time.



You will need to buy a 12 volt test light. You can find these at any Auto parts store for about $5-$10. Start by dis-connecting the Battery Negative cable, and connect the test light between the cable end and the battery post. It should light because of those items that are always on.



Remove the fuses for those items, usually the Radio, (the clock and station memory) the ECM, BCM and, Alarm, etc., if so equipped. Make sure you know where to put the fuses back in when you're done. Then start to remove the other fuses. When the light goes out, you have found the circuit that your drain is coming from.



That will narrow it down quite a bit. There are usually multiple things on the same circuit, so you may have to unplug some individual items to find the particular thing. A wiring diagram helps here, to know what's on that circuit. Ask at the library for a book with these.



Once you find the offending circuit, just put that fuse back in, and start unplugging things on that circuit, until it goes out again. That's your drain. One time I found that it was the cigarette lighter receptacle had a bunch of crud in it, so that it was as if it was always on!

Answer 2

Go to your auto parts store or a large store like Wal-mart. Buy a 12 volt "test light".



Here is the procedure we use to isolate a battery drain. Remove negative battery cable from the battery. Using a 12-volt test light, hook one end to the negative battery post the other end to the negative battery cable you just disconnected. The test light will glow or “light” if there is a drain. If the “light or glow” is faint, that is probably normal draw for the clock or computer. If the “light or glow” is bright, then there is a large drain. That should be corrected. Now start removing and replacing the fuses one by one until the light goes out; that one will be the circuit with the drain.

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Once you find the correct circuit you can either a) leave the fuse out if it is not important (cigarette lighter or some accessory not in use) follow all the wiring back and disconnect it just before the equipment on the circuit. If the lamp is still lit then you have a wire that is shorted to ground. If the lamp goes out when you disconnect the equipment, then the equipment itself has a ground or is pulling current all the time. Repair, remove, or replace the defective equipment that is draining the battery.



Most commonly the drain will be either after-market stereo or car alarm system, or a under hood light that is left on by mistake or a faulty switch.

Answer 3

hi there, you say the alternator is good , but even if you have had it checked to see if it is charging, there is micro circuit modual in the back , one of it's jobs is to disconnect the charging circuit from the battery when the engine is switched off, this prevents the power in the battery from draining back out through the alternator, so even though it shows that it is giving a good charge, it will drain your battery over night if that switch is no good . So if i were you i would change the alternator , before it costs you another battery.

Answer 4

if it drains overnight there is a light, radio, or something staying on, leaving a cell phone charger plugged in a couple days can also even if not on phone, one trick I use is turn everything off, if you have a hood light inside unplug it, then dissconnect negative side of battery, make sure all doors are closed so no lights are on, then touch the terminal to the negative post, if you get a slight spark, something is still on, take one fuse at a time out, making sure the doors are closed, until you get no spark, then you have the circuit narrowed down as to where to look, like radio, or whatever the fuse says it powers.

Answer 5

Put an ampmeter on the battery cable and pull fuses until the load goes away,that will point you in the right direction.

Answer 6

most common is a loose connection betwwen the battery posts and the wire terminals, if they are as tight as they can be and you see a small space any where or they move a tiny bit thats most likley the problem, new cables or a metal wedge will solve this problem usualy.

Answer 7

My sister had this problem on a 2008 Lexus. Turned out that the DVD player was not shutting off when the ignition key was removed. She was told that she was not driving it enough and that this was normal. Her dealer arranged for the DVD manufacturer to install a new unit and the problem went away.

Answer 8

If I turn my car off with the radio on will it drain the battery

Answer 9

it could be an interior light draining the battery. The first thing i would check is the boot light not switching itself off when the boot is shut, the best way to check for this is to get someone else to lie in ur boot while you shut it they willl then be able to see if the light goes off when boot is shut.

Answer 10

It sounds like your alternator is going bad but not completely, which is why it allows you to drive around but it is still draining your battery. A week alternator and the cold battery is enough to drain the battery just enough to not start. The only other thing it could be is that something in your car is on like a light or something. My guess would be that your alternator is going out. If the alternator is less than 5 years old my theory may be wrong

Answer 11

a short anywhere in the system, very hard to figure out. could be possibly a bad alternator, or a bad started...these could be check at an auto parts store. there is a simple test to test these

Answer 12

Battery Keeps Draining

Answer 13

Car Battery Drain

Answer 14

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RE:

my car battery keeps draining, its new, and the altenator is good, what can be making the battery drain?

its the 3 battery i got, its a duralast, when i bump started the car it ran with no problems, so the altenator was charging, the new battery has been in there for 3 weeks, with the other two batterys they only lasted a week. is there something draining the battery and what and how do i check for...

Answer 15

my car battery was good, changed that one the alternator's diode would stay open and that was killing my battery so I replaced both items, had voltage regulator put in, lasted five days drove around running errands came home turn it off, had to run another errand wouldn't start replace ignition switch still wouldn't start, tried jumping it gave it approximately 10 minutes started took off jumper cables tried starting it agn not happening gave another 10 minutes.

Answer 16

something electrical is shorted out or on, such as dome light stuck window or doorlock switch, electric anntenna,security alarm. rear defroster rear wiper motor

Answer 17

take car to autozone and have them test your starting charging systems, if not that you have an open circuit or short