why cant my battery stay charged?

Question

i bought a re-built (used) battery for my car after the first battery died,after a day or two it was starting my car up just fine untell,i tryed to start it up and it didnt start my car up so i got a jump-start from my father and let it run for 30 mins to re-charge up the battery,but after i shut the engine off and tryed to start it back up,it didnt crank up not once or not at all.so,i bought another used battery because i thought maybe i had bought a bad battery.i installed the new used battery and drove on it for one day and the same thing happend,(something drained the battery).so,i got another jump-start,after i got the jump start,i disconected the negitive cable from the battery(testing the alternator)didnt anything shut off so,im guessing it's not my alternator it's the battery,can anyone please share with me there suggestion or advice. thank you!

Answer 1

One thing though...Why on earth would you buy a used battery? That just showed you how long it lasted. Always go for a new battery.

Answer 2

Get a new.....not used....brand new battery.



There could be a short somewhere, or an open circuit. Get a test light, connect the ground wire to the negative terminal of the battery...then touch the pointy end of the test light to the positive terminal of the battery. The test light should come on briefly and then fade, if there is no short, or open circuit. If the light stays on, and is very bright....then you have an open circuit somewhere draining your battery. The way to fix this is to keep all that hooked up and start pulling fuses from your fuse box, one at a time. Pull one, test the light, if the light stays on. It's not the right one, put the fuse back before you pull the next one. And keep going until the light goes out (going through the fuses). When you find the fuse that turns the light out, whatever circuit that fuse is for is causing the problem.



Hope I helped.

Answer 3

Used batteries are not rebuilt, they are old yes but not brand new.

Also, the old test of disconnecting the battery while running is not recommended nowadays, (it can fry electrical stuff on newer cars).

What I would suggest is to check for a parasitic load. Get an multimeter and put it in the amperage mode. With the battery disconnected, connect it between the battery terminal and the cable. You will notice a certain set amount of amperage. Now with this still connected, have a buddy locate the fuse box and have your assistant pull one fuse at a time. When you see that the amperage drops, you have isolated the circuit that has something draining your battery. Now it will be a matter of finding what exactly is draining it (common things can be a shorted relay, the trunk light that stays on all the time, etc.)

Answer 4

well there are two answers from what little i know

1

you have a drain some where that you are not awere of

look for a light left on, under the hood or in the trunk or in side the car

wait untill you have shut the car off and then check

2

you just might have got another bad battier



also a drain on the battery can make a good battier go bad

Answer 5

Why did you buy two used batteries instead of getting one inexpensive new one (with a warranty) almost anywhere including Walmart!



If it's not the battery or alternator, though, it could be the battery cables.

Answer 6

sorry to tell you that battery was not rebuilt its sooo expensive to be cheap not go to napa,autozone whatever you have and buy a good battery one you can take back if there is a problem or possible your alternator is no good check belts that drive alternator good luck or u have a short check trunk light, hood light take those light out if possible see what happens is radio off when u turn car off good luck

Answer 7

Go buy a new battery, quit messing with used stuff and then get your charging system checked out to make sure everything is working right, autozone will check it for free.

Answer 8

1

Answer 9

it could have a weak or dead cell in it.

Answer 10

what kind of car?