Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 03-14-2010, 09:33 PM
Registered User
 
Join Date: Jul 2008
Location: Maine
Posts: 10
84 300D Battery loses charge very fast

OK, I'm stumped. The car will not start due to no battery charge.

The alternator tested OK by our mechanic, and the battery has been tested at Sears.

I brought the car to the mechanic and they thought it was the voltage regulator, so it was replaced and appeared to be working.

Tonight my girlfriend took the car to the grocery store and the same thing happened. The car started fine at home, she drove there with lights and defrost on, parked the car and when she came out there was nothing.

Usually I am very capable of sorting out these problems, but I am now stumped. The car jump starts easily, which is why I thought it was the battery. And I am not sure if it is coincidence that it happens to be raining each time this happens.

Any ideas what this may be?

So far things that I have checked are:

Battery (Only 1 year old, and recently checked at Sears)
Alternator
Negative ground to chassis
Voltage Regulator is new

What else could it be? Relay? Car grounding itself? Bad cable? Ignition? Starter?

Thanks,
Nate

Reply With Quote
  #2  
Old 03-14-2010, 10:09 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 5,265
Have you put a multimeter on the terminals of the battery? Do that first. Sounds like a shorted cell to me. The alternator works, and potentially there is enough voltage for some things to happen marginally. The short doesnt dissipate all jumping current, so the car will start. However, once the car is off, the short will dissipate the stored energy in the other cells, and the car wont be able to produce starting current.

What is its voltage after sitting a while? When was it recentlhy checked at sears? what did they do? A battery on an operating alternator will show a voltage that may look OK. Ditto for a recently charged battery, a surface charge may still show an OK voltage for some time.

Next thing I'd do is remove the positive cable and put the multimeter in series with the cable terminal and the battery terminal. Get a reading for how many mA or A youre pulling. If it is over, say, 25-50 mA, then there likely is something shorted in the electrical system. If so, then you need to start using the multimeter in place of fuses to see where the draw is coming from... and track it from there.

Good luck!
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #3  
Old 03-14-2010, 10:56 PM
Registered User
 
Join Date: Jul 2008
Location: Maine
Posts: 10
Thanks JHZR2!

I was thinking that it was probably a short somewhere. When I put a voltmeter on the terminals it read about .4A. (without cables connected)

I wasn't really sure what that meant. Should there be current flowing from positive to negative with the cables disconnected? Half an amp seemed like a lot to me, but I'm not really that knowledgeable about electrical.

Tomorrow I will double check myself, and see if the current is going to the chassis.

When Sears tested the battery they just bench charged it and let it sit over night to see if it would lose it's charge.
Reply With Quote
  #4  
Old 03-15-2010, 12:08 AM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 5,265
Quote:
Originally Posted by Baer View Post
Thanks JHZR2!

I was thinking that it was probably a short somewhere. When I put a voltmeter on the terminals it read about .4A. (without cables connected)

I wasn't really sure what that meant. Should there be current flowing from positive to negative with the cables disconnected? Half an amp seemed like a lot to me, but I'm not really that knowledgeable about electrical.

Tomorrow I will double check myself, and see if the current is going to the chassis.

When Sears tested the battery they just bench charged it and let it sit over night to see if it would lose it's charge.

It sure seems to me that if when completing the circuit via an ammeter, if you are seeing .4A, then you have your culprit.

Frankly, id replace battery first and foremost. Given that it has gone through a bunch of discharge cycles, IMO it is not reliable anymore, especially capacity-wise. So Id put a new one on (first testing it with your meter to see what a relevant reading should be), and see what that does. If it goes flat, then charge it with a battery charger and put in the old one until you find the solution.
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #5  
Old 03-15-2010, 01:47 AM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
Battery

(Long Drawn Out...Yadda,Yadda,Yadda from yours truely.)

Unfortunately, the only modern day TRUE test of a Battery is to:
1.Check the Electrolyte level,and correct.
2.Trickle Charge for up to 72 hours
(IF you even suspect the Battery may be worth saving! 'Slower is always better!)
3.Test for Voltage at Naked Terminals (After burning off Surface Charge)
(Minimum 12.75 Volts D.C.)

THEN:

4. Test for Electrolyte Density OR LOAD TEST with Resistance Loader.

The Gals and Guys @ Advance,AZ,Sears,WM,O'reilly's,Etc.,Etc. only
know what their fancy digital testers tell them...

Their tests CAN be valid but only within specific parameters:
The battery MUST be Fully Charged before testing (Among Others)

YOU AIN'T GONNA GET A FULL, SLOW CHARGE FROM ANY CHAIN OPERATION!
__________________
'84 300SD sold
124.128

Last edited by compress ignite; 03-15-2010 at 01:55 AM.
Reply With Quote
  #6  
Old 03-15-2010, 10:23 AM
bustedbenz's Avatar
Registered User
 
Join Date: Feb 2007
Location: Valle Crucis, NC
Posts: 2,283
Quote:
Originally Posted by JHZR2 View Post
It sure seems to me that if when completing the circuit via an ammeter, if you are seeing .4A, then you have your culprit.

Frankly, id replace battery first and foremost. Given that it has gone through a bunch of discharge cycles, IMO it is not reliable anymore, especially capacity-wise. So Id put a new one on (first testing it with your meter to see what a relevant reading should be), and see what that does. If it goes flat, then charge it with a battery charger and put in the old one until you find the solution.
What am I missing here? Shouldn't connecting an ammeter directly to the + and - of a power source essentially be using the meter as a short-out between the poles (similar to laying a wrench across the battery terminals and producing a welder)? I stuck an ammeter into a household AC power strip one time just out of curiosity and ignorance. The result was that the meter tried to create a dead short between the two prongs, the resultant heat melted my positive meter lead, the power strip (one of those 6-outlet things) was fried instantly and the household breaker tripped. Isn't putting an ammeter across a dc battery causing the same effect (or at the very least, not a reliable measurement) or is this a different principle? If I'm dead wrong here then forgive me for interrupting the thread, but that seems... odd to me, unless I've missed something major. I'm not an electrical person either.

Measuring volts across a battery's + and - I understand perfectly. But I was under the impression that it was impossible to do so on an amp setting.
__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL
Reply With Quote
  #7  
Old 03-15-2010, 10:36 AM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,835
Quote:
Originally Posted by bustedbenz View Post
What am I missing here? Shouldn't connecting an ammeter directly to the + and - of a power source essentially be using the meter as a short-out between the poles (similar to laying a wrench across the battery terminals and producing a welder)? I stuck an ammeter into a household AC power strip one time just out of curiosity and ignorance. The result was that the meter tried to create a dead short between the two prongs, the resultant heat melted my positive meter lead, the power strip (one of those 6-outlet things) was fried instantly and the household breaker tripped. Isn't putting an ammeter across a dc battery causing the same effect (or at the very least, not a reliable measurement) or is this a different principle? If I'm dead wrong here then forgive me for interrupting the thread, but that seems... odd to me, unless I've missed something major. I'm not an electrical person either.

Measuring volts across a battery's + and - I understand perfectly. But I was under the impression that it was impossible to do so on an amp setting.
yeah, only do this with the key off and everything turned off on the car...
even headlights will fry your meter...
setting the meter to ma and leaving the neg cable on the battery, and hooking the meter between the battery and the positive cable will show what the clock, and anything else running is pulling. it should be around 25ma...
500ma (.5A) is a LOT
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
Reply With Quote
  #8  
Old 03-15-2010, 10:50 AM
Registered User
 
Join Date: May 2007
Posts: 896
Quote:
Originally Posted by Baer View Post
OK, I'm stumped. The car will not start due to no battery charge.

The alternator tested OK by our mechanic, and the battery has been tested at Sears.

I brought the car to the mechanic and they thought it was the voltage regulator, so it was replaced and appeared to be working.

Tonight my girlfriend took the car to the grocery store and the same thing happened. The car started fine at home, she drove there with lights and defrost on, parked the car and when she came out there was nothing.

Usually I am very capable of sorting out these problems, but I am now stumped. The car jump starts easily, which is why I thought it was the battery. And I am not sure if it is coincidence that it happens to be raining each time this happens.

Any ideas what this may be?

So far things that I have checked are:

Battery (Only 1 year old, and recently checked at Sears)
Alternator
Negative ground to chassis
Voltage Regulator is new

What else could it be? Relay? Car grounding itself? Bad cable? Ignition? Starter?

Thanks,
Nate

If I were you, when your finished with the car for the day, disconnect the battery until the next morning. The next day, reconnect the battery, and try and start the car. If it starts, the battery is holding its charge, if it doesn't, you know the battery is suspect. If the battery passes that test, I would recheck the alternator, by disconnecting all the wires attached to it, including the heavy battery cable, put your multi tester in continuity mode, and place one lead of the tester on the alternator battery connection post, and the other lead to the engine block or any ground point. If you get a continuity reading, it means that one or more of the alternator diodes have failed, and is allowing current to flow from your battery to the engine block. I had that happen to my car, and if the battery were left connected, it would totally discharge in a matter of a few hours with the key in the off position.
__________________
96 E300d
Reply With Quote
  #9  
Old 03-15-2010, 11:25 AM
Ether's Avatar
Go S Class or go home
 
Join Date: Oct 2001
Location: Lawrenceville, GA
Posts: 758
Make sure your glow plug relay is not stuck closed. This condition can drain your battery very quickly.
__________________
Joe

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1980 300SD - 495k miles - 'The Ambassador'
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Former Family Members
95 C280
73 280SEL
90 300D
87 300SDL (X2)
86 560SEL
84 300D
80 300SD

Reply With Quote
  #10  
Old 03-15-2010, 12:42 PM
Registered User
 
Join Date: Mar 2009
Location: San Diego
Posts: 3,537
Make sure you have a FULLY charged and good battery and do the followings with a DMM:

1) With the car running. Check the voltage of the battery terminal. It should be normal 13-14.4V. This verifies the alternator is working.
2) With the car off and all lights, radio off. Remove key. Disconnect -ve terminal and measure any current draining the battery. It should be mininal < 500ma. The residual current is for clock or alarm etc.
3) If it draws a lot of current then go the fuse box and remove each fuse then measure the current across the fuse terminal. Most should have 0 current, except the fuse to the dash (it should be small also ).
4) If there is a massive short somewhere then there may be a burning smell.
5) If there is a short then the fuse would blow unless the fuse is over-rated.
6) I have resolved a lot of shorts in this manner.

Good luck.
__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.
Reply With Quote
  #11  
Old 03-15-2010, 02:06 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 5,265
Quote:
Originally Posted by bustedbenz View Post
What am I missing here? Shouldn't connecting an ammeter directly to the + and - of a power source essentially be using the meter as a short-out between the poles (similar to laying a wrench across the battery terminals and producing a welder)? I stuck an ammeter into a household AC power strip one time just out of curiosity and ignorance. The result was that the meter tried to create a dead short between the two prongs, the resultant heat melted my positive meter lead, the power strip (one of those 6-outlet things) was fried instantly and the household breaker tripped. Isn't putting an ammeter across a dc battery causing the same effect (or at the very least, not a reliable measurement) or is this a different principle? If I'm dead wrong here then forgive me for interrupting the thread, but that seems... odd to me, unless I've missed something major. I'm not an electrical person either.

Measuring volts across a battery's + and - I understand perfectly. But I was under the impression that it was impossible to do so on an amp setting.

You are right - battery terminal to terminal is shorted and would blow the ammeter fuse if just touched to both sides.

Ammeter needs to be inline with battery cable, and .4A shouldnt blow it.
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
Reply With Quote
  #12  
Old 03-15-2010, 10:31 PM
Registered User
 
Join Date: Jul 2008
Location: Maine
Posts: 10
Quote:
Originally Posted by pimpernell View Post
If I were you, when your finished with the car for the day, disconnect the battery until the next morning. The next day, reconnect the battery, and try and start the car. If it starts, the battery is holding its charge, if it doesn't, you know the battery is suspect. If the battery passes that test, I would recheck the alternator, by disconnecting all the wires attached to it, including the heavy battery cable, put your multi tester in continuity mode, and place one lead of the tester on the alternator battery connection post, and the other lead to the engine block or any ground point. If you get a continuity reading, it means that one or more of the alternator diodes have failed, and is allowing current to flow from your battery to the engine block. I had that happen to my car, and if the battery were left connected, it would totally discharge in a matter of a few hours with the key in the off position.
If it were a bad diode, is this something that can be replaced? Or is a new alternator needed?

Also, I did not realize you cannot touch the multimeter to the two terminals Luckily I did not blow the meter. That is where I was getting the .4A. I need to do some rechecking and report back here.

I have not had a chance to work on the car today, but thank everyone for the replies. I wish Cumminsforum were this helpful for my other diesel!
Reply With Quote
  #13  
Old 03-15-2010, 10:36 PM
Registered User
 
Join Date: Jul 2008
Location: Maine
Posts: 10
Also is there any way to tell if the battery is bad/shorting itself with the multimeter? I am still pretty new to using one of these.
Reply With Quote
  #14  
Old 03-16-2010, 05:26 AM
compress ignite's Avatar
Drone aspiring to Serfdom
 
Join Date: Feb 2004
Location: 32(degrees) North by 81(degrees) West
Posts: 5,554
DMM (or Analog)

Baer,

Youse gets one O those Manuals with your DMM?

(Direct answer to your last question: See my first reply in this post. [#5] )
"4. Test for Electrolyte Density OR LOAD TEST with Resistance Loader."
http://en.wikipedia.org/wiki/Hydrometer

If not this will get you started:
http://assets.fluke.com/appnotes/automotive/beatbook.pdf

Excellent Reference source:

http://us.fluke.com/fluke/usen/Training/Safety/default.htm

http://us.fluke.com/fluke/usen/Training/Demos/default.htm

http://support.fluke.com/find-sales/Download/Asset/2071940_A_w.pdf
Attached Thumbnails
84 300D Battery loses charge very fast-screenhunter_10-mar.-16-05.34.gif   84 300D Battery loses charge very fast-screenhunter_11-mar.-16-05.35.jpg  
__________________
'84 300SD sold
124.128

Last edited by compress ignite; 03-16-2010 at 05:36 AM.
Reply With Quote
  #15  
Old 03-16-2010, 08:46 AM
Registered User
 
Join Date: May 2007
Posts: 896
[QUOTE=Baer;2426868]If it were a bad diode, is this something that can be replaced? Or is a new alternator needed?

Yes, the diodes can be replaced, but the biggest problem is being able to find them. The other thing is, there may be another problem with the alternator that may have caused the diode to fail. If you do the test, and you do find continuity between the alternator battery connection and the alternator case or other ground point, you will have your current drain isolated.

__________________
96 E300d
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 12:35 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page