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Battery drain

2003 - 2009, roadster, coupe, facelift
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parabolica
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Battery drain

Post by parabolica » Tue Jul 27, 2021 8:54 pm

Car wouldn’t start at the weekend after a week of sitting; battery was dead flat. Charged the battery, car fired back up. Been using it a few days but once again, car is dead. Haven’t check the battery yet but 99.99% it’s the same issue.

Best case it needs a new battery - fine. But mind started wondering - what if the alternator is goosed instead? Or some other parasitic drain. I can’t think of anything that would drain the battery so it’s either the 10 year old battery or a knackered Alt.

How can you test the alternator? Would it throw a code on Carly maybe? Don’t fancy spending £££ on a new battery only for the same to happen again within a few days.

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bigwinn
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Battery drain

Post by bigwinn » Tue Jul 27, 2021 9:01 pm

Hi bud

You ok?

Think it’s worth double checking you have nothing switched on at all- I fell foul of the sidelights

After that it’s worth checking the amps not volts on the battery- but would be surprised it degraded that quickly unless you have an alternator on the way out

Ive in the past rigged a volt meter inline to see what the drain is on the battery when it’s all locked up- google what it should be drawing in that state then if it’s higher pull fuses until you find the culprit?

Not fitted anything new recently?
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parabolica
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Battery drain

Post by parabolica » Tue Jul 27, 2021 9:06 pm

Hey bud,

No, nothing new fitted. Double checked everything was off when I refitted the battery. Found a thread on here from a few years back -someone had the exact same issue and it was the alt. Just looked up a test on YouTube so going to get stuck into it tomorrow - after my dad comes and gets me with a spare battery so I can get home!

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Battery drain

Post by bigwinn » Tue Jul 27, 2021 9:09 pm

Saw on another thread which is worth a search

Instead of replacing the alt look also at replacing the back part of the alt (can’t remember for the life of me what it’s called) hold on
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Battery drain

Post by bigwinn » Tue Jul 27, 2021 9:10 pm

Found it

Firebobby was talking about testing and replacing the regulator
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Battery drain

Post by bigwinn » Tue Jul 27, 2021 9:11 pm

If the forum helped you, why not help the forum back. Thats the Z4 way! :thumbsup:

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parabolica
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Battery drain

Post by parabolica » Tue Jul 27, 2021 9:11 pm

:thumbsup:

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