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Old 9th May 2019, 15:59   #1
racing green rover
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Default Battery parasitic drain

Hi whilst I'm still waiting for an oil cooler my battery seems to be going flat regulary the alternator is charging at 14.5 volt and with the heated rear window on drops to 13.8 but rises back to 14.5 volt when I rev it, the battery is only 2 month old and that was reading 12.5 volt when I removed the negative lead over night to see if it had dropped although today it was at 12.2 volt. I have tested the amperage by putting a meter between negative lead and negative post of the battery and it reads 0.25 of an amp although I got it down to 0.17 after holding leads tighter on battery lead and terminal is this an acceptable reading or too high.
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Old 9th May 2019, 17:26   #2
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Are these readings with the car locked and asleep? 170ma is much too high if its the case . My LR Discovery 3 drain is 10ma after about 1 1/2 hrs after locking
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Old 9th May 2019, 18:35   #3
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With everything turned off doors shut after about 20 minute
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Old 9th May 2019, 21:47   #4
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If your battery is discharging over night with the negative lead removed your battery is a dud.---
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Old 9th May 2019, 21:55   #5
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I had it disconnected for 2 nights the next day it was 12.7v day after it was 12.2v
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Old 10th May 2019, 10:57   #6
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Quote:
Originally Posted by racing green rover View Post
I had it disconnected for 2 nights the next day it was 12.7v day after it was 12.2v
Those are the exact symptoms of an internal battery problem.

You definitely need to take the battery back to where you bought it from to get a replacement under guarantee.--
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Old 10th May 2019, 12:17   #7
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Thank you both for your help I've exchanged the battery for a new one I also got a test probe and checking the fuse box most lit up green negative with everything turned off but fuse 1 5 and 9 I think lit up red positive I had the passenger door open but turned the interior lights off
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Old 10th May 2019, 13:35   #8
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Quote:
Originally Posted by racing green rover View Post
Thank you both for your help I've exchanged the battery for a new one I also got a test probe and checking the fuse box most lit up green negative with everything turned off but fuse 1 5 and 9 I think lit up red positive I had the passenger door open but turned the interior lights off
What brand of battery was it, and are you still getting a 0.25amp drain from the vehicle?
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Old 10th May 2019, 16:24   #9
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At the moment it keeps fluttering from 0.20 to 0.25 it's been on for about 20 minute I will give it another 20 minute the battery is a Banner red power I've left it about 45 minute the reading dropped fluctuating between 0.13-0.14 amp

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Old 10th May 2019, 17:25   #10
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Originally Posted by racing green rover View Post
At the moment it keeps fluttering from 0.20 to 0.25 it's been on for about 20 minute I will give it another 20 minute the battery is a Banner red power I've left it about 45 minute the reading dropped fluctuating between 0.13-0.14 amp
Still seems high, ideally you should have no more than 0.03 amps as far as I understand it (0.01 to 0.02 amps is most common).

What car stereo system do you have fitted, and do you have a dash cam?

A faulty alternator with a bad diode can drain a battery, normally the battery would go flat overnight if this was the case.
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