fred_ 166 Report post Posted March 19, 2018 Hi all, I currently have an E30 which is experiencing a battery issue. Initially I thought the car arrived with a faulty battery however I've since replaced it and it has also drained this one. The problem has now got worse as the car is no longer turning over, despite hearing the starter motor trying its best. Any suggestions on what it might be? Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted March 19, 2018 Is the alternator working correctly? Are there any items that are drawing current when the car is parked up and key out of the ignition? Check at night to see if there are any stray lights on. Listen if the heater fan perhaps is spinning in the background. Any doors or boot lid kept open when parked up? Quote Share this post Link to post Share on other sites
fred_ 166 Report post Posted March 19, 2018 47 minutes ago, C-130 Hercules said: Is the alternator working correctly? Are there any items that are drawing current when the car is parked up and key out of the ignition? Check at night to see if there are any stray lights on. Listen if the heater fan perhaps is spinning in the background. Any doors or boot lid kept open when parked up? Think that's a likely suspect. Is there anyway of checking to be sure? Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted March 19, 2018 Well, in that case I would expect the battery control lamp to stay on after start and while driving. You can measure the voltage across the battery while the car is running (in your case you will need to jump start first). Normal reading while car is running and alternator is charging the battery should be between 13 - 14.5 V. Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted March 19, 2018 Dads original E30 battery actually lasted longer than it's alternator! The battery would drain enough to stop it starting after 7 to 9 days. We replaced the 9 year old battery, and it was fine for a few months, but then the same thing - even though the alternator appeared to be charging. The alternator was rebuilt by a local auto sparkie, and it was fine after... It was just never charging the battery quite right, and would eventually run the battery down, then the sitting pushed it past the point of cranking fast enough to start. So I suggest checking the voltages (as above), but running the alternator up on a test rig may show something too (or fit another one anyway). Keep the new battery charged with a decent charger too - leaving it under charged will shorten it's life. Quote Share this post Link to post Share on other sites
fred_ 166 Report post Posted March 19, 2018 10 hours ago, C-130 Hercules said: Well, in that case I would expect the battery control lamp to stay on after start and while driving. You can measure the voltage across the battery while the car is running (in your case you will need to jump start first). Normal reading while car is running and alternator is charging the battery should be between 13 - 14.5 V. If I can get it to start again that is! I've put my battery on a charger overnight so hopefully it will have full juice to crank assuming the drained battery was causing the issue. Thanks for the suggestion! 2 hours ago, Allanw said: Dads original E30 battery actually lasted longer than it's alternator! The battery would drain enough to stop it starting after 7 to 9 days. We replaced the 9 year old battery, and it was fine for a few months, but then the same thing - even though the alternator appeared to be charging. The alternator was rebuilt by a local auto sparkie, and it was fine after... It was just never charging the battery quite right, and would eventually run the battery down, then the sitting pushed it past the point of cranking fast enough to start. So I suggest checking the voltages (as above), but running the alternator up on a test rig may show something too (or fit another one anyway). Keep the new battery charged with a decent charger too - leaving it under charged will shorten it's life. It sounds like a very similar issue. Hopefully it's immediately obvious when I get it started Quote Share this post Link to post Share on other sites
C-130 Hercules 571 Report post Posted March 19, 2018 If you don’t run the car daily then get an isolating switch for the battery. Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted March 20, 2018 Based on the questions you are asking, it would be simpler/quicker to take it to an Auto Sparky & get it checked/confirmed in 5 - 10 mins. Isolating switch is hardly necessary - the current draw at rest is absolutely minimal (assuming no issues) adding to - a battery self discharges over time anyway. Quote Share this post Link to post Share on other sites
Driftit 2078 Report post Posted March 20, 2018 (edited) If you feel like a drive into town a friend of mine would be happy to help. He knows E30's inside out thanks to all the sh*t that went wrong with mine and other bimmersporters. His name is Brendon. Hope Hickman Auto Electrical. Address: 38 Monmouth St, Grey Lynn, Auckland 1021, New Zealand Tell him Dan from the USA sent you. Edited March 20, 2018 by Driftit Quote Share this post Link to post Share on other sites
