840CI battery drain


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  1. 840CI battery drain 
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    Hello all, I have a 1997 840ci and I have a battery drain problem. If I disconnect one battery so that all power is supplied by the remaining one, and then I measure the current from this battery after switch off, I usually get the foollowing. About 1.2 amps is drained for 16 mins and then the drain falls to 50 milli amps. However somtimes at the 16 min time the battery drain does not fall and 1.2 amps continues to flow out of the battery and flattens the battery quite quickly.

    So two questions.

    1. Is 1.2 amps normal for the 16 min period?????

    2. Does anyone know what enacts the change in battery drain after 16 mins????

    I would welcome any help with this.


    New info and problem solved. The reason for that above was that the starter solenoid would often not engage and I attributed that to low battery voltage, however after 3 days of checks I found the problem. With 12.7 volts on the battery, when I try to start the car the voltage on the solenoid actvation coil is only 7.4 volts. so somewhere along the 'line ' 5 volts has gone missing. I am off to the dealer on Monday to get them to check it out. I guess this voltage goes from battery to ignition switch to gear change park position to foot brake and finally to the solenoid coil. If anyone has any info on what could be the problem I would like to hear it.

    Last edited by nickbance; 23-06-2012 at 19:58. Reason: Problem found

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