Battery charging

I think I may have a problem with the battery on my BMW 123d. The stop/start feature has stopped working (normally the first sign of the battery getting a bit tired). In the past it has done so in bad weather combined with short journeys and normally a quick charge will sort it out. On this occasion, not only has the car been used on longish journeys, but very little load has been put on the battery. To make matters worse it does not seem to charge.

My CTEK charger will not even light up to indicate it is charging (works OK on my Triumph TR7). I tried a conventional charger that only raised the voltage from 12.4 to 12.8 and sounded a bit noisy, so I switched if off.

When I start the engine I get 14.5 volts at both the battery in the boot and also the charging point under the bonnet. The battery tester tells me it needs charging. MJ Marsland I then received a second email: It appears the battery charger has a problem with connection. It has an LED indicator in the lead that indicates the state of charging. One of the pins was loose and was causing an intermittent fault (a common fault according to CTEK). Also, not having used the car for a day, the battery voltage was 12.18V this morning. MJ Marsland There are various conditions that will prevent the stop/start system from operating: Outside temperature is below 3°C Outside temperature is above 35°C Car interior has not yet reached set temperature Engine has not yet warmed up Battery charge is low Directly after car was driven in reverse Steering wheel is turned after car has stopped Stop and go traffic (at least three stops made in short succession at a speed of less than 15mph) Gear selector in 'Sport' or 'Manual' ABS was activated before stopping Windscreen is fogging up With this in mind and now having rectified the problem with your charger, I would first try charging the battery. If the battery fails to take a full charge, it may be time to replace the unit.