> #1 piece of advice I can give you is to stop making any assumptions. I concur.
> So the first step is to pull the negative battery cable, charge the battery, > then put a test light between the battery and the negative cable. If the > light is on you have parasitic draw. Until you've proven that you know > nothing. That actually doesn't work very well, because several systems in the car draw power for a period after power is restored. 'Booting up' as it were. My preference is to loosen the negative battery clamp, place the awl of the test lamp (or the negative probe of a multimeter set to read current) against the center of the top post and the free wire of the test lamp (or the multimeter's positive probe) against the outside of the clamp, then carefully lift the clamp up so that it no longer makes contact with the battery post, while not interrupting the circuit. It's a bit fiddly, takes both hands and some care. What this does is _never_ interrupt the power supply to the car, while still inserting the lamp/meter into the circuit. That should give you a clean indication of the steady-state parasitic draw on the battery. (Or use a sufficiently sensitive clamp-on DC ammeter, for no fuss no muss.) I start with the lamp, if it glows there is a substantial load and you have your answer. If not, I then repeat using the meter instead, so that I can get an indication of how many milliamps the various always-on circuits draw. Fewer is better, even a 10mA parasitic load adds up over days and weeks. Consider a 100AH battery. A 100mA parasitic draw (huge) will pull the battery down to 80%, the lowest any lead battery should ever be allowed to get without reducing its life, after about a week. One courtesy lamp is around 1A of current, so they can put a serious hurt on your battery if stuck on, even just overnight. (Dome lamp, or glove box, etc.) -- Jim _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
