Battery on my car keeps going flat. I charge it up and next day it's flat again. How do I check if it 's the

Question

battery that's finished, or whether it's something that's draining it?

Answer 1

check the fluid in its cells it sounds like they or some are empty..... if there is not enough fluid then top it up

Answer 2

The simplest approach would be to connect a DC voltmeter across the battery terminals and get some one to rev up the engine. If the voltmeter reading increases as the revs increase, then the alternator and charging circuit are OK. Therefore your battery almost certainly requires requires replacing.
However before taking that expensive step, you should also check that there is not some huge drain on your battery when the car ignition is switched off (the best way is to use a 'clip on' ammeter on the positive battery lead). If there is, then you can isolate the cause by removing a fuse at a time until the ammeter stops reading - then look at what component/s the fuse protects and locate which is draining the current.

Answer 3

You need to change your battery. If the battery doesnt retain the charge that is a sign that it has come to the end of its life. It cant be the alternator cos if it was the alternator the battery wouldnt charge at all and you would have to keep accelerating in order to keep the engine running.

Answer 4

If over 2.5-3 years old it could be knackered, and not holding a charge.
There could be a bare spot in a cable or wire that makes it drain off, or a similar condition in the starter or alternator.
You can check for wire or similar problems by disconnecting the negative cable and letting it sit overnight. Reconnect, and if the battery is okay, then get to an electrical expert.
Also, if you take battery to an auto parts shop they can test it, probably for free.

Answer 5

Simple

Charge it up, disconnect the lead to the positive on the car, leave a day and see if it has flattened itself.

If flat - then battery is dead

If ok, then connect a bulb in series between positive terminal on battery and battery lead. If bulb comes on, then something in the car is drawaing power. If it can only dimply light a tiny bulb (3 watts or so) then it seems ok, (clock, alarm etc), if it can light a bigger bulb (21 watt) then you have a fairly high drain going on.

Answer 6

If you go to your local tool shop Draper make a battery/ altneator tester which will cost you about £10 this will test both the components and tell you whats wrong, you dont say what car it is but the replacement battery will be between £25 - £50 if thats the case

Answer 7

A couple of answers here, either the battery is dead, then it might be easier (and safer) to just get another.

It may not be the battery, might be something wrong with a starter motor or another engine part.

Something wrong with your cars immobiliser?

Is there anything that stays on when the car goes off? Anything in the cigarette lighter?

How long between using the car? Is it used everyday?

Hope that helps.

Answer 8

Two things – (1) If the batteries not charging, i.e. Alt/Reg, you will have the bat warning light on. (2) To drain a fully charged car battery in the time implied you would need to have left something like your headlights on.

Answer 9

it could be one of many things.it could be battery,alternator, bad earth.
1st id check the battery if its not a sealed unit take the caps off check water level, if water is low top it up and charge it .get an altimeter and check alternator charge with car running it should charge at about 12 amps.check all leads on battery and where the earth straps mount the body of the car clean of any corrosion and debris.

Answer 10

IT ALL DEPENDS HOW LONG THE BATTS IN THE CAR ,IF ITS ON the car for 3/4/5 yrs its probably the battery...any shorter than that you might have a dodgy altenator...then again ... if the car only gats a low amount of mileage the batt might not get enuff charge,,,,take it to an auto electrician

Answer 11

It's the alternator