Author Topic: Battery or alternator??????  (Read 1115 times)

Offline veedubmk2golf

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Battery or alternator??????
« on: 09 January 2007, 21:06 »
the last two mornings ive had to jump start my car, after this its fine and when i leave it for a while and come back it starts ok, it just seems to be a problem when its left over night and when i come back to it in the morning it doesn't start. i do think its the battery but just wanted other plp's opinion, thanks

Offline Thom89

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Re: Battery or alternator??????
« Reply #1 on: 09 January 2007, 23:31 »
Take you car to your local garage for an instant battery test.. expect to pay between £35/45 for a decent battery
Tom

Offline GeorgeBurgess

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Re: Battery or alternator??????
« Reply #2 on: 10 January 2007, 01:37 »
Could be something to do with the residual drain on the battery? If you have an amp meter disconnect the positive terminal and bridge it with the meter. Anything more than 0.2Amps isnt good. Making it go flat over night would be a bit more than that tho...

A knackered alternator can draw current and hence drain ur battery.

I had this problem last week.


Offline FBF

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Re: Battery or alternator??????
« Reply #3 on: 10 January 2007, 02:41 »
try diconnecting the battery over night then connect again in the morning.  see if the battery has held the charge or not

Offline Ben Lessani

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Re: Battery or alternator??????
« Reply #4 on: 10 January 2007, 04:00 »
take it to kwik fit or tom farmers for a free battery and alternator test. sounds like your battery needs charging up as a result of a parasitic load (unwanted drain on the battery). to test for a parasitic drain get an ammeter (capable of 10a or more) and disconnect the +ve from the battery and bridge the ammeter in between battery +ve and +ve wire, it should be less than 0.07, although with an alarm a load of 0.1A can be tolerated. remove fuses one by one until the current drops to 0, then find what on that circuit is draining the battery. easy peasy.

happened on my car recently, and it turned out to be the parcel shelf covering the boot close switch, so the boot light was continuously on drawing 0.35a. your alternator is only for topping up a healthy battery, not charging it from being flat, if it ever goes flat, it needs charging properly. its also worth checking the levels in the battery and topping it up with some distilled water when charging.