Diary of a Second Hand 15 year old Beamer (Maintenance - Battery Drain included..., BMW E39 520i year 2000 Engine 1995cc) M Series.
Workshop/Diary - Monitoring Battery
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Contents Page
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If you would like items to be added, please contact me via email, found in introduction on content page
02nd December 2014 - I decided to bite the bullet and re-insert Fuse 4 today and see how long the battery stays up. 03rd December 2014 - So far, so good, battery at cold rest: 12.3V Engine with load running at 1000rpm 13.56V Engine without load after a minute with load at 1000rpm 13.72V During a very short run around a block Onboard computer reads - brief 14.1 and 14.2V longer run pending 04th December 2014 - Still with fuse 4 in car started 3:45pm OBC reads 12v Battery 11.8V (before shutdown)at 1.5k rpm 13.9V (Engine Running) approx 2-3 mins.) Lasted 4 days
06th December 2014 - Battery flat 3:15pm, taken out fuse 4 again and returned a re-charged or recyled battery, there is still a problem with the fuse 4 circuit somewhere it seems. ( Note: Interior lights have been checked, and most of the bulbs have been changed to lower LED voltage, did this early November) 08th December 2014 - BM Started 12:07 fuse 4 out - 10 min drive Battery ok 12th December 2014 - BM Started 13:45 fuse 4 out Battery ok 15th December 2014 - BM Started 12:42 fuse 4 out 13.9 V Running 12.0V Standing 17th December 2014 - BM Started 8:50 fuse 4 out - 60 min drive 14.0V Running 13.0V standing 19th December 2014 - BM Started 12:30 fuse 4 out - 13.9V Running 4 mins 12.2V standing 22nd December 2014 - BM Started 10:45 fuse 4 out - 13.9V Running 2 mins 12.1V standing (15 days ok) Retaining charge is a little weak and could still be something to do with the alternator.. Note: Taken off the battery isolator and secured the main negative earth strap - solid contact 24th December 2014 - BM Started 9:30 fuse 4 out - 13.9V Running 15-15 mins (17 days ok) 27th December 2014 - BM Started fuse 4 out - (20 days ok) 28th Decemeber 2014 - BM Started 11:35 fuse 4 out - 13.9V Running 2 mins 12.7V standing 21 days ok 30th December 2014 - BM Failed Start 12:10 fuse 4 out - Battery dead Total 23 days
Definately a short somewhere in the interior light circuit - February 2015 the fuse has been replaced after long periods where the battery voltage has stayed up. and voltage has drained near enough over night to a couple of days with the fuse replaced.
With Fuse 4 IN
With Fuse 4 OUT
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Update: May 2015 - Check out 'Specialised Tools' in Content page 3 - Battery and Alternator Tester
