As a rule, one would assume a battery defect would occur in winter. That it also happens in summer, particularly in the case of luxury cars, is due to the unbelievable amount of consumers.

Indeed, the cars themselves also have a life of their own. In the past, when the ignition was switched off, one could be sure that everything else was switched off too. Even the windscreen wipers stopped in the middle of the windscreen if the ignition was turned off. Nowadays, they camly carry on until they've reached their end-position.

When starting the car the same thing can happen. In the beginning, in the dead of winter, I regularly got a shock, because after turning the ignition key, the starter did nothing. All that had happened, was that the on-board electronics had simply taken a short time-out. Probably to make sure that the engine parts didn't bump into anything when it started turning (joke).

Our cars are starting to have lives of their own. In the meantime they can, even now, find their own parking places, at least the prototypes can. If it carries on this way, if the car doesn't like it's owner, it may be able to look for someone new, all by itself!

However, to be serious, if through too many extravagances, the battery is discharged to the extent that the car will no longer start, that's where the fun stops. In the past it was only the clock, still analog of course, that only used up a few milliamperes.

Todays luxury class cars draw, shortly after switching the ignition off and leaving the car, up tp 10 Amperes and more. Also the time that it takes before this has dropped to below 50 mA, varies from a few seconds to sometimes more than 40 minutes.

At the moment one assumes a waiting period of 30 minutes when searching for a hidden consumer. This period will have to be revised, because, in particular fully equipped vehicles simply don't make it possible.

It used to be that even the quiescent current itself was measured at far less than 50 mA. In the meantime however, measurements of just under 40 mA have been confirmed. Where does this come from, that so much current is necessary? Is the vast amount of equipment really at fault?

Not really, as usual, one has to take a number of factors into consideration. To be precise, it's all about the hardware which is necessary, even after locking the car. A few examples are, the remote control, the alarm system and the existence of further connections with the world outside.

Indeed, here the engineers have also performed differently. Specifically, it's all about the part of the electronics, which wakes up the system. How much current is really saved here? Are e.g., the remote controls recognised early and rejected without effort, or is the whole system activated with every action, even if it comes fom another vehicle?

Where the system has hardly any influence, are the regularly occurring outside effects. Is it very windy and the movement of the tree-branches next to the car are constantly being recognised by the alarm system? If the recognition sensors are very sensitive and some time is taken before the system goes back into stand-by mode, in extreme cases this can lead to the battery being ruined. 07/13