Recently discovered a problem that creeps up with cars built in the last 10 years or maybe more... Parasitic battery drain... Extended electrical usage after the vehicle is shut down... Not just delays...

Resulting often in a 'dead' battery the next time you want to start the car... It is fairly common and can be from a number of problems, but usually, it is a bad relay... The big issue is not identifying the result - dead or low battery... It is isolation of the cause... Normally we are talking about an electrical-off drain of somewhere around .005 amps or 5 milliamps... If the faulty system produces a drain in the .5 - .05 range, then sooner or later... DEAD BAT... Troubleshooting of this is labor intensive... because you need to check every electric system independently... and it is not a test from an OBD reader... One preventative action when identified is to drive/charge every day for about an hour... to get the battery up to full strength... This assumes a good battery and an alternator putting out 14-15 amps...

Still trying to find an auto manufacturer that will have some way of doing this without hours of testing individual systems... Auto should have a small battery drain - nominal...