Car problem diagnosis please

[Mattk]

I think I know what the problem is but as it involves money i thought id get a 2nd opinion!

The car is not used very frequently and it is not uncommon for it to sit on the drive for a couple of weeks at a time or more without being used. The battery has always sounded fresh however..until this week. Yesterday the battery was dead as a dodo so i get a jump start and it fires up. I take it for a good 15 mins drive to juice it back up. I arrive back home turn it off and then start it up again witb no problem. Today the battery is dead again.
Now as I say I think I know what the problem is but would appreciate confirmation.

Thank you.

[chas2008]

How old is the battery ?
batterys have a limited life regardless of how often they are used, 3-4 years being quite common. They usually fail at the 1st sign of winter or a cold spell. A lot of parts suppliers/accesssorie shops offer a battery testing service

[jake-the-peg]

Sounds like a dying battery. They will often restart after a run as the engine is warm and they will hold the charge for a while.

Sometimes the alternator will not be charging the battery enough but it's more likely just the battery

[logic]

it sounds as though your battery is not holding its charge,
maybe 15 mins running didn't put enough power back to start it more than once,
or maybe your alternator isn't putting enough back in,
either way, unless you have a test meter of your own,
( and it doesn't sound as though you have,) i would take it to an accesorie shop and get it checked out, most do this for free anyway.

[logic]

Sorry, Chas. Jake, i must'v been typing as you posted.
pete.

[TWR]

If the battery in not a sealed unit check the cells for distilled water, top up if necessary, take the car for an hrs run or so, what you are doing is taking out of the battery your short recharge, more than likely you will have the radio, wipers,heater,demister & whatever you use ON this in turn will kill the small charge you have put in it, check your fan belt! is it tight? Is there a DIM Ign light on on your dash? that indicates the alternator is on it's way out.

[mightymorris]

YOU SAY THE BATTERY IS DEAD
1 if the battery is just flat then recharge it overnight an get it tested
If the battery is totally dead then recharge it and turn everything off and lock the car
1 If the batt light is glowing then your alternator is duff
2; if your car is a hatch back then remove the parcel shelf to make sure the boot light has gone out
3 if your car has a boot you will have to find a way to check the light goes out
4 Best test is to put an ameter in lie between the battety terminal and lead with everything off and take the leakage reading should not be more tham 0.3 amps after all the computers have shut down any higher then thats why your batt goes flat

[Mattk]

thanks guys. had an alternator go before and this doesnt feel like the same problem. battery is only 2-3 yrs old.
is that old enough to die?

[chas2008]

yes, quite possible depending on the quality & usage of it, it may have had a 3 year guarantee

[weeal]

I had a problem similar with my Alpha - turned out that one tiny little rear bulb was on constantly (Italian electrics eh) and wouldnt go off - unless I took the fuse for the lamp out at night the car was dead in the morning

It got worse tho and I changed my car

[kepla]

Hi Matt,
Looking at the problem logically, it must be one of three things:
1) The battery isn't getting enough charge into it. Either you are not giving the car a long enough run without lights, fan and radio, or your alternator is not charging too well - fan belt, perhaps ?
2) What charge the battery is getting in to it is leaking away again. Perhaps you have an electrical problem which is using a bit of current while the car is supposed to be 'off' - interior light on, for example, or faulty alarm system ?
3) The battery is no longer capable of holding onto the charge properly. There is a good reason why batteries are only guaranteed for two or three years ! If the battery has been left discharged for a while it will lose capacity.

I would agree with what others have said that your first step should be to get the battery fully charged up and then drive round to somewhere with the test rig to test out your battery and alternator. From then on you should have a good idea whether 1, 2 or 3 above applies. Remember that short journeys will take more out of the battery than they put into it and kill the car in other ways too.
Best,
Kevin.