The battery in my '88 300E is being drained constantly. I measured (car not running) the following current drains at the fuse numbers listed below. Do these seem excessive for what is on them?


Fuse C 8.4 mA
Fuse 9 50 to 60 mA fluctuation

Thanks for any help.

That would put the amp hour drain at 1.7 amp-hours per day. It would take you about 2 months to drain the battery. If your battery is dead sooner than that, either it's not charging properly or the battery is shot.

I don't have a schematic, but those current drains are perhaps for the radio.

HTH

Joe

Fuse C is the alarm and a few other things, fuse 9 is the radio. The total draw borders on excessive, the radio circuit being most of it. As Joe pointed out this shouldn't take out a battery unless left sitting a long time. We usually get upset if the total current gets to 100ma, Although this amount is more common on later cars with many control units with memory.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Technically, you don't leak voltage, you leak current (flow of electrons).

P E H

Folks,

Thanks for the input. I wanted a second opinion on the amperage values as the car has been acting abnormally since it was hit (while parked) about a year ago.

I believe the battery was run down due to a broken trunk light switch. I got hit from the back and never noticed that the switch post was bent. I drive every day so the battery was charged back up daily. I went on vacation and it was dead when I came back. I recharged it. Then we had a nasty snow storm and it sat for a week. Dead again.

So, now I need a trunk light switch and a new battery.

BTW. P.E. was correct about leaking current not voltage. What can I say other than it was late.

Thanks again. This site has helped me more than once now.

Kmoran101,

One more technical nit: There is no such word as amperage but there is the word voltage. The correct word for a fuse rating is amperes which can be abbreviated amps. The word for electron flow is current with the unit in amps, milliamps, kiloamps, etc.

IE: This circuit is protected by a 5 ampere fuse.
The current used by the glow plugs is 80 amps.
This light bulb has a voltage rating of 120 volts.

If we use the correct technical terms it promotes better understanding.

P E H