1984 300D

1.) New alt 129x alternator. (works fine)
2.) New Battery fully charged. (changed battery numerous times)
3.) Ground cables checked and okay.
4.) Additional heavy wiring to battery from alternator.
5.) New battery terminals.
6.) A drain it seems but it is not constant.

My car is possessed. I had done all of the above about 6 weeks ago after posting questions and getting feedback from forum. You see the car will be okay for what awhile and then bam, like Saturday afternoon it goes dead in the mall parking lot. My wife gets it home, I change the battery out that afternoon, and Monday morning the battery is totally dead. Nothing, nada.
What is weird is that when I pull the fuses and check for current drain, it's like sometimes it show's a drain and other times not. Tonight its in the garage and the "a" fuse which is the window lift, front right/rear left was showing a definite parasitic drain of anywhere between .12 to .05 volts when I turned off the lights and came in the house. This was without the fuse in the panel.Twenty minutes earlier it was zero. Another early reading today showed a drain of about .05 A few weeks ago I had no drain at all. When I put a multimeter between the battery positive terminal and the cable end the multimeter reads a steady .13 My daughter drives the car most of the time. She did mention that the rear drivers side window sometimes works. Its kinda of an iffy thing. So what do I do?

A. Pull door panel and check motor and wires behind panel?
B. Remove wood where window switches are located?
C. Shoot car? This is my vote.

__________________
Cliff D.
Central Illinois
1987 300SDL 200K
1984 300D Turbo 245K

First of all, your voltage tests are meaningless.

You need to repeat the tests with a proper ammeter that can register below 100mA. The vehicle should have a total loss of less than 60mA if you intend to keep the battery charged for more than one week. Once you climb above 100mA, you're on borrowed time, but, it should still last for a couple of days without a problem.

I'd check the vehicle for current draw by placing the meter (ammeter) in series with the negative battery terminal.

Report back on what you get.

Don't shoot it, Just threaten it and shake your fist.
My guess is there is some power draw when its off. perhaps a switch or something is left in the on position slightly or not disengaging, How to pinpoint what it is will be hard.
I would just start from one side and work to the other checking all contacts and switches and cleaning them, at least you wont have to do it in the future and that may fix your problem.

__________________

1981 -300D w123 - Daily driver


"Even a clock that does not work is right twice a day"Polish proverb.

Brian, I do have a "proper" multimeter capable of reading mv's. EDIT amps, and milliamps. It's actually a very nice one, however my skills at electrical deduction are found lacking. The readings i posted, are as i said from the positive side of the battery. I will repeat them if needed, from the negative side, but irregardless, the battery is being drained dead in short order. Very short order and, and no there are no switches on. I checked, again.

__________________
Cliff D.
Central Illinois
1987 300SDL 200K
1984 300D Turbo 245K

you rreadings are in volts- we need to know how many amps are being drawn . unhook the neg terminal of the battery, and take a reading. it is prolly gonna be hi.- as staed by Brian, it should be less than 100MA.

then go to the fuse panel. one lead on batt terminal, the other on variuos fuse spades until you find where the draw is. then you will at least know which circuit it is on, and you can continue down that route.

How's the power antenna? mine shorted out and was drawing 9 amps!

__________________
1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

like everyone said you need to use a amp meter. volts is just the intensity of the electricity the amps are the amount that are being drawn. ever heard the saying its not the volt but the amps that kill you. the amount of amps drawing from the circiut is the amount of electricity being used. also it could be that you have the alternator wired wrong and this would lead to a drain of the battery. if you want to find out if that is the case then just disconnect the alternator and let it stand over night if the alternator was the case then you have found the problem.

__________________
http://i148.photobucket.com/albums/s...titled-1-3.jpg
1981 300d

The first thing that popped into my head while reading this is a sticky ignition switch possibly shorting a small amount of current. This might explain the intermittant nature of the problem. Do as the others suggested and do an amp test and if you get a reading, try wiggling the ignition switch... Just a thought...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Okay, will recheck in the morning as soon as I can. Thanks for input guys.

__________________
Cliff D.
Central Illinois
1987 300SDL 200K
1984 300D Turbo 245K

Questions for you:

Regarding (#1) How do you know the alt works fine?
(#4) What's the additional heavy duty wiring?

If you measure the voltage at the battery terminals with the engine off,
charged battery you should see around 13.8 volts.
Start the car. The voltage should come up to around 14.4 if the alternator is working. Turn on the headlights, AC blower. It should stay close to 14.4 if the alternator is up to snuff. If so, shut it off. If not, look at the alternator belt, wiring...

If it stays at 14.4 proceed to the next test to look for leakage current.

Disconnect the neg battery cable. Connect the two test leads from the meter one going to the battery neg terminal and the other to the neg cable that you just took off. Place the meter in the 100MA current mode. Not DC voltage. There is usually a 10amp position for the positive cable. Hopefully you wont need to read leakage this high.
As Brian mentioned you should read less than 60MA (milliamps). If more than 60-100ma start pulling fuses while watching for a drop in current.
A drop will lead you to the culprit.

I'm bettin' the alt is not working properly.

I am using the alt 129x alternator and wired this beast per the thread discussion. The alt 129x thread went into detail about upgrading the wiring from the alternator to the battery because of the increase in amps. I even ended up e-mailing Roy with Mercedeshop about this. Its been sometime back but I did post this same problem. Say 2 months ago. I thought it was fixed, so I deleted the post. Saturday afternoon I did put a multimeter across the battery terminals as the car was running. The multimeter indicated the battery volts increased from its previous reading to a higher level. so I thought that it was charging. I did check the belts. and they feel tight. I will check alternator in the A.M. but I really think its working fine.I will check milliamps as per suggestion. At this point I just want this problem to go away. Thanks.

__________________
Cliff D.
Central Illinois
1987 300SDL 200K
1984 300D Turbo 245K

Numbers... we need numbers. Measure it and post 'em. We'll sort this out.

Why? Keeping threads on the forum helps people diagnose their problems using the search function.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Okay, In on my wireless Tablet PC and these recordings are in real time.

Volts across battery terminals: 12.95 volts before turning car on. Remember I had been using the battery for testing purposes from the previous evening.
Using method described, with ammeter hooked up between negative cable end and the fuses, I checked each once. The highest reading in mv was. 003 on any of the fuses. So no appreciable drain to speak of. Most of the fuses read -0-

The car was allowed to get good and warmed up. the results where @ idle 13.81-13.73 with blower motor and lights turned on. During this time as I was standing next to the car I heard a device cycle on and off without a particular specific time interval.I tried to determine where the sound was coming from using a too foot stick against the various rotating parts and next to my ear, but no luck.

this is interesting: I just reached inside the car turned the lights and blower motor off. I began to write the measurements on my tablet pc. are of a sudden .the multimeter began reading 12.32 volts after that re clicking" sound of a device came on. The car has been running now approx,for thirty minutes.
fine minutes passed and I tuned the headlights on briefly. the millimeter on the battery reads 12.28 volts.
Attaching the clamp on ammeter, to the cable running from the alternator to the battery positive shows -O- volts.
Okay the car bas vow been running about an hour and that "clicking" device sound which made the multimeter jump door to 12.32 has not came back on or cycled again. the battery reading is now 12.18. Is my alternator toast??

__________________
Cliff D.
Central Illinois
1987 300SDL 200K
1984 300D Turbo 245K

Why is it so difficult to connect the ammeter in series with the negative battery terminal and report back with results?

Disconnect the negative cable.........put one lead of the ammeter on the cable.........put the other lead of the ammeter on the battery post............read the ammeter...........post the result.

We already explained that voltage readings are not relevant to this issue.

alright well you found out that it isn't in the car's fused circuity so it is the alternator. Now you need to check your connections and make sure they are tight. If any of the connections are loose it could cause the symptom that you talk about. If all the connections are tight then you need to take the alternator out and take it to a shop so you can test it. it may be the voltage regulator. hope this helps.

__________________
http://i148.photobucket.com/albums/s...titled-1-3.jpg
1981 300d