300SL Power Drain

[hifeverz]

It appears I have some sort of power drain from an unknown source. Every week, if the car sat, undriven, would need a recharge . I replaced the battery (New Optima Red), thinking that was the culprit. I fully charged the battery and with the new battery I installed an item called "Priority Start" which shuts down, in the event of a power discharge (leaving lights on, etc.) to the battery of all components safely to a level that allows u to start the vehicle. The car sat in the garage for 5 days and the dome light did not go on, leaving me to believe the Priority Start did disconnect the battery due to some sort of power drain. I turned the ignition switch on twice and on the second time the system (12v) reconnected to start the car. It is a time saver though there is apparently a power drain somewhere.

Any hints as to what to check for??? The car stays in the garage unlocked and all doors shut. The power antenna does not feel hot to the touch as if on all the time.

Thanks,
Hz

[tecqboy]

The trunk latch / switch for the trunk lamp has been known to break. This causes the lamp to remain on when the trunk is closed. Since you can't see it, it goes un-noticed. It will draw the battery down in 2 to 3 days. The best way to find a problem is to measure how much current is being drawn with everything off. That is, key out. Only a few components in the alarm system and remote door lock system are still "alive". Typical draw is not more than 1/2 amp. Don't dismiss the possiblity that your original battery was bad and was self-discharging. The battery buddy is a good idea and I believe a standard feature on most new cars. If you aren't comfortable with electrical work, a shop check of the entire charging system might be in order. It's a long shot, but a leaky diode in the alternator would also cause a drain as well as a failed component in the voltage regulator. (Those diodes leak electrons, not water.)