Alternator or Battery.

[theshedman]

Hi all, the last couple of days my car sounds like it hasn't got much battery power when starting up for the first time, but the rest of the day it has been fine. Today it wouldn't start at all. Battery sounded dead. I put jump leads between son's car and mine and it started first time. Wasn't sure if it would be the Battery or the Alternator that was the problem. Anyone got any ideas. Cheers. Shed.

[jake-the-peg]

probably the battery - car takes most power starting from cold - lots of thick oil to push about etc.

Once it's started and topped up a charge it's fine until overnight.

Wife's car was exactly the same a couple of weeks back and I replaced the battery and it's been good as gold.

Time of year nights getting colder etc.

[theshedman]

I thought it was the battery last time it happened but then it turned out to be faulty starter motor that was draining battery. Thanks jake.

[theshedman]

For the answer I meant to put.

[jomifl]

Run the engine and turn the headlight on full. If they get brighter when you rev the engine a little then it is probably the battery tho' it could be discharging through a dodgy diode in the alternator.

[jake-the-peg]

Can be but the battery's the most likely culprit

You could put a multimeter across ot and see what the alternator's putting out but - especially as it's this time of year my money's on the battery.

If it were June I might be less sure

[Hopkirk]

You say that Jake, but an AA man told me that lots of batteries die in very hot weather, as well as cold.

[Andyvon]

Standard lead/acid batteries don't last for more than a handful of years at best anyway. You can only expect the cheap batteries to last a couple of years before they start to struggle. More expensive ones will last a year or two longer before they start to fade.

If your battery is more than three or four years old shedman it's probably dying. In that case, a new battery will solve the problem and make sure the car starts every morning this coming winter.

[theshedman]

Hi, thanks for all the answers. I haven't got a multimeter to test it with so I will have to take it to the garage and get them to look at it for me. Probably is the battery but best to let them check I think. Thanks again. Shed.

[Hopkirk]

Andyvon is a little pesimistic on battery life I think.

My seven year old car has its original GM battery, which shows no signs of struggling.

[sad old git]

Hi Shed. I had similar problems a few months ago when my battery kept going flat after a short period (eight weeks or so). I put this down to because I use my car for many stops and starts in one day and the battery hasn't a chance to recharge, however on a bit of advice from a friend I bought a " Solar trickle charger" from a very reputable electronics store and installed it in the rear window of my car and connected through to the battery

[TWR]

Is your fan belt tight? Is your battery type that is fill able? check your dash board is there a faint red light showing? if so, alternator, are the Battery terminals tight? are the connections at the starter & earth wires tight? lot of Qs but the answer is there.

[wilkesneil]

to test if its altenator simply start your car and look to see if the battery light comes on.
if its on keep engine running for 2 minutes to see if it goes off.
if the light stays on it means the altenator isn't charging the battery so the light will come on, if light doesn't come on then it could be battery.

my battery died about 6 months ago and the rac checked it and told me that the starter motor was over voltage causing the battery to die , also it was killing the altenator as it was working harder and if i didn't have a new battery they would all be gone with in 2 months. I have changed the battery, took it to local audi specialist and everything else was perfect.

[theshedman]

Hi all, thanks for all the answers. Wife took it to garage yesterday and they put it on something that told them the alternator and starter motor were fine but battery wasn't working properly. They have now put in new one and it started first time this morning so hopefully it will be fine now. Thanks again for the help. Shed.