The switched power supply, +15 or ignition + as it is also called, is still an important connection point in the car. We have published about this once before, in September 2014 to be exact. In 2014 we wrote that finding a switched power supply was getting harder and harder and that this required another viewpoint from after-market system manufacturers.
Of course there are still cars that have a ‘classical’ switched power supply, with the desired specifications: it can’t drop when starting the car and it should immediately stop if the engine is turned off. Nevertheless, more and more often we see that there are still some problems that can appear. And that has everything to do with the charge that the switched power supply experiences due to being connected to an after-market system. Even though this charge is minimal in most cases, currently there are cars that are being dimensioned so strictly that even the slightest charge can already be detected by the system and can lead to problems.
For after-market system installers it might perhaps be wise to take this into account on beforehand when installing a system. It is always wise to have some alternatives at hand, like a CAN-interface, if the situation above might occur.
