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Battery charging issue

Old 17 March 2017, 06:41 PM
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frisby
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Default Battery charging issue

Hi,

Sti battery related issue here. Car cut out and not turning over indicating flat battery. New battery fitted and car runs but battery won't hold charge and battery light not showing on dash.

Any key areas to look at to narrow down what the problem might be?

cheers

frisby
Old 17 March 2017, 07:03 PM
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Dubzy
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Its most likely an alternator related fault. Test the voltage output with a multi meter at the alternator with the engine running and should be above 13v. Its also worth checking the earth and power straps from the battery and alternator.

If you have a low reading then its probably down to worn brushes in the alternator.

Last edited by Dubzy; 17 March 2017 at 07:06 PM.
Old 17 March 2017, 07:06 PM
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frisby
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Originally Posted by Dubzy
Its most likely an alternator related fault. Test the voltage output with a multi meter at the alternator with the engine running and should be above 13v.

If you have a low reading then its probably down to worn brushes in the alternator.
Yep that sounds about right. Would that account for the battery light not lighting up on the dash when the ignition is on?

How easy is it to replace the brushes? Or is it a case of just buy a new one??
Old 18 March 2017, 02:35 PM
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alcazar
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The clue is in the dash charging light not coming on.

If the bulb goes, there is no excitation field to the alternator, so it doesn't produce charge. Change the bulb out and all should be fine.
Old 18 March 2017, 02:58 PM
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frisby
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Originally Posted by alcazar
The clue is in the dash charging light not coming on.

If the bulb goes, there is no excitation field to the alternator, so it doesn't produce charge. Change the bulb out and all should be fine.
cheers for that. 1. Where do I get a bulb? 2. Will it involve any soldering?
Old 18 March 2017, 05:14 PM
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How long is it holding charge for ?
and after market ICE or alarms ?
Old 18 March 2017, 07:40 PM
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frisby
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Has a tracker fitted but not active and a 3rd party alarm.

Think the battery light in the dash not turning illuminating could be the key.

apart from a blown bulb is there any other reason it wouldn't light up???

Last edited by frisby; 18 March 2017 at 07:41 PM.
Old 19 March 2017, 08:43 AM
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alcazar
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Not usually.

What model year are we talking? Bulbs are W5W capless on the older cars, and take about 15 minutes to fit, no soldering.

Two screws to get the upper binnacle cover off, three screws to get the instruments out, pull forwards, and unclip wiring, dead easy.
Old 19 March 2017, 06:11 PM
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frisby
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It's an 05 forester sti.
Old 20 March 2017, 01:02 PM
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Should still be easy. Electronic speedo so no speedo cable, just wiring clips.
Old 20 March 2017, 04:56 PM
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Don Clark
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Originally Posted by frisby
It's an 05 forester sti.










T5 1.4W wedge base (without the socket)
Old 20 March 2017, 08:41 PM
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Thanks don, much appreciated.

Cheers

Stu


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