Car Battery ... Is There A Way To Test If The Problem Is The Batt Or The Car?

[joko]

Im having car trouble - the battery keeps dying - but it will jump start ...

i drove for about an hour the other day to recharge it, and it was dead again 2 hours later

have had to jump it 3 times today, after only leaving it for 20 mins or so ...

is there a way i can make sure its a fault with the battery and not the car before i go and buy a new one?

thanks

[joko]

there is no warning light for a battery issue - though one came on a couple of days ago about changing the oil ... could that be it?

when i jump it, it runs fine.

going to add some oil tomorrow

[bhg481]

Most places that sell batteries will test it for you free of charge.

[jason.p]

If you take it into your supplier (kwikfit etc.) They will be able to test it for you. I'm sure they will be honest with you

[gingejbee]

Kwikfit....and honest. Two words not normally found in the same sentence!

[RobNorth]

If the light was indicating "change oil" your car needs a service and you should also change the battery - the cost/benefit benefit is a
no-brainer. If the light was indicating "add oil" you are neglecting your car and it could be very costly indeed....I hope it's the former - best wishes.

[bhg481]

Have you checked that the connections between the battery and the battery leads are very clean? The starter motor draws several hundred amps and dirty connections will cause a large volt-drop and prevent the starter motor from turning. Jump leads are normally attached to the car leads, as opposed to the actual battery terminals, so dirty connections will not prevent jump leads starting the car.

[Gizmonster]

Can I ask - what kind of journeys do you do in your car??
The reason I ask - my missus had a problem with her battery a while ago.
We took it to a garage to be tested and was told that the battery and alternator were fine. They then asked what kind of journeys she made. My missus usually only travels a mile or 2 at most, each journey - this is insufficient to keep the battery charged. They told her to take it up and down the motorway for at least 10 miles at a nice steady 70 mph to let the alternator charge the battery up.
It was fine after that, so if you're only travelling short distances, the solution could be a quick whizz up and down the motorway .... but I'd take it to a tester first, to check the alternator and battery out - a reputable firm will do this for free.

[KARL]

I once felt certain that there was some sort of undue drain on the battery (of indeterminate age) in my car, went to a garage where I was asked to leave the car until the next day, I left it with a second battery which was new. When I returned I was told both batteries were useless - they had been connected to the car and drained - proof was the low voltage at the end.

I did my own rummaging around and disconnected a suspect wire. Two years and more the old battery is still in the car doing fine, the other will perhaps one day be installed (if the other finally actually fails).

I had the advantage of a battery charger of my own - these are not that expensive and really worth owning. First check I would suggest is get the battery charged up (preferably out of the car), then reinstall it and every time the car is to be parked for more than a few minutes, disconnect the battery.

If it starts the car for some days then the car is likely unduly draining it when connected. If it still goes flat quickly then the likeliest cause becomes the battery itself. Another way is to thoroughly charge it up (disconnected) and then leave it disconnected (for example overnight) and see if it will eventually start the car - if not, the battery is likely poor.

It is also important to consider the possibility that the alternator is failing to provide a useful charging current.

All the above assumes that disconnecting the battery does not cause undue complications with assorted electronics in the car. As stated already, good contacts are important or else the car will not quickly charge up the battery - and two hours may not be enough if the battery is already flat.

[joko]

thanks all - just checked the oil level ... its totally fine ... is the battery issue perhaps causing electronic warning lights to come up when there is no fault?
i am goign to top it up a bit anyway - but it was about 3/4 in between the two notches.

i do fairly short journeys, and often go days without using it at all.

yesterday i drove along a fairly long dual carriageway and back at around 60mph most of the way, for about an hour or so.
the car was dead again about 2 hours later.

this morning i put the jumper on and tried and tried to start it and was about to give up, not wanting to empty it completely and suddenly it just spluttered to life, so i drove around the block for about half an hour, then went to my appt - and it was dead 30 mins later ...

its not completely dead - there are lights on the dash and stuff like that works ... it just wont start.

the connections are not 'dirty' but there is a small amount of rust on the screw bit and a tiny amount of green filigree on the metal inside the 'bolts' - is this enough of a problem to warrant cleaning etc? how do i do it?

thanks

[tonyav]

Also check the earth lead connection where it is connected to the car body, make sure it is clean and the bolt is nice and tight. Better still unbolt it and give a small area around the bolt hole and the earth connector a rub with a bit of emery cloth and re bolt it up.

[malagabob]

You can get a battery alternator tester for a few pounds When connected it will show if your alternator output is OK.