TRD-Rob Posted August 8, 2013 Share Posted August 8, 2013 The cars gone though two battery this year but thought that might be down to not using it enough,but something's making me think differently now as I just jump started it let it run for about five minutes but as soon as I disconnect the leads the car just dies just wanted to know what can kill a battery when your not using it ? And where not talking months of not using it We're talking a couple of weeks. Thanks for any info. Quote Link to comment Share on other sites More sharing options...
red_zebra Posted August 8, 2013 Share Posted August 8, 2013 When the cars running it shouldn't be running off the battery, sounds like alternator to me. When it is running do you have any warning lights on? Also have you measured the voltage across the battery? Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted August 8, 2013 Share Posted August 8, 2013 Car alarm? Quote Link to comment Share on other sites More sharing options...
TRD-Rob Posted August 8, 2013 Author Share Posted August 8, 2013 No light come up no,And the volt meter reads 8.3 on 200,but that's only telling me what I already know which is that the battery is Knackered. - - - Updated - - - Car alarm? Would a car alarm really kill it that fast tho ? Quote Link to comment Share on other sites More sharing options...
wewsupra Posted August 8, 2013 Share Posted August 8, 2013 Car alarm? yeh that Quote Link to comment Share on other sites More sharing options...
Al Massey Posted August 8, 2013 Share Posted August 8, 2013 No light come up no,And the volt meter reads 8.3 on 200,but that's only telling me what I already know which is that the battery is Knackered. - - - Updated - - - Would a car alarm really kill it that fast tho ? You're wrong mate, sorry to be blunt. With the engine running you should read upto 14v ish as you are not checking the battery power but the alternator. When the engine is off, that is when you will see how much charge is in the battery As said you don't need a battery to run the car just to start as the alternator powers everything and trickle charges the battery. Quote Link to comment Share on other sites More sharing options...
TRD-Rob Posted August 8, 2013 Author Share Posted August 8, 2013 You're wrong mate, sorry to be blunt. With the engine running you should read upto 14v ish as you are not checking the battery power but the alternator. When the engine is off, that is when you will see how much charge is in the battery As said you don't need a battery to run the car just to start as the alternator powers everything and trickle charges the battery. I can't get a reading when the car is running as it will only run when being jumped and won't that give a False reading as it's been powered by another battery ? Quote Link to comment Share on other sites More sharing options...
Al Massey Posted August 8, 2013 Share Posted August 8, 2013 I can't get a reading when the car is running as it will only run when being jumped and won't that give a False reading as it's been powered by another battery ? When you disconnect the jump leads does it run on its own? The engine doesn't run off a battery mate it runs of the alternator. You can actually disconnect and remove a battery once running as it is obsolete in a way. If the car doesn't run without the jump leads or a battery then your alternator is goosed mate Quote Link to comment Share on other sites More sharing options...
TRD-Rob Posted August 8, 2013 Author Share Posted August 8, 2013 When you disconnect the jump leads does it run on its own? The engine doesn't run off a battery mate it runs of the alternator. You can actually disconnect and remove a battery once running as it is obsolete in a way. If the car doesn't run without the jump leads or a battery then your alternator is goosed mate I tried it twice,the first time I jumped it I left it running for about one minute then started to pack up and the car died after about 30sec,the second time I ran it for five minutes but it died as soon as the leads came off. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 8, 2013 Share Posted August 8, 2013 I am pretty sure it's not charging, an alternator or charging circuit wiring issue. Jump off a none running car. Rev your engine, voltage should go up to over 13.5 volts. Put headlamps and heated screen and heater blower on, on your Supra. Rev again. If voltage stays lowish and unchanging it's definitely a charging issue. Slight chance your crank damper has failed and the alternator is not turning fast enough when loaded up. Do a "Tipex test". Quote Link to comment Share on other sites More sharing options...
Abz Posted August 8, 2013 Share Posted August 8, 2013 You're wrong mate, sorry to be blunt. With the engine running you should read upto 14v ish as you are not checking the battery power but the alternator. When the engine is off, that is when you will see how much charge is in the battery As said you don't need a battery to run the car just to start as the alternator powers everything and trickle charges the battery. Sounds alternator related! Quote Link to comment Share on other sites More sharing options...
TRD-Rob Posted August 10, 2013 Author Share Posted August 10, 2013 Cheers for the help guys ill try solve it and deep you updated. Quote Link to comment Share on other sites More sharing options...
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