528 i baseline current draw BAttery drain/ current draw

nalaleah53 · Mar 24, 2013

I posted about a month ago about a battery related issue. (I replaced the alternator since then and learned how to check it with the OBC

...)
This car is sitting about 5 days and driven on weekends. It has been dying at the end of that one week time with flashing gauges and now misfiring. The positive terminal is very hot when it dies.
I am now looking at battery drain and yesterday I measured about "1.8 amps" current draw with "everything" turned off other than the trunk being open. (It was daytime and I didn't see the trunk light or figure where the switch was to depressn it..?
Can anyone tell me what the baseline draw should be? ( approx .5 milliamp like some other cars as mentioned in u-tube videos?) So far, I have only checked the trunk fuses and the drain doesn't change. I'm about to discover where the rest of the fruses are inside but it seems like that will lead to a 2 person job or lots of climbing back and forth to the negative battery terminal.
I have read of a few documented draws like the A/C Final something something heat sink and the blower but does a 2 amp draw point to anything specific?
I need to mention there is an mostly not working passeneger seat that I will start with next but it has been in that state a long time before this started...

edjack · Mar 24, 2013

The final stage unit and the audio amp are prime suspects.

Typical sleep current is in the range of 50 mA. You've got something that is not turning off.

This is a better way to diagnose parasitic drains than pulling fuses. You measure the voltage drop across the fuse.

See this PDF:

http://www.nateronline.com/Technica...hnical_Bulletins/2007.10.02_Battery_diagnosis_Excessive_static_current_draw.pdf

bluebee · Mar 25, 2013

It's my firm opinion that everyone should document each problem so that the next person can start where they left off, to improve the documentation for the next person.

To that end, here's my documented quest for parasitic current draw searches.
(It's your job to improve upon that so others benefit.)
- The most often recommended methods to diagnose overnight parasitic battery current drain in the BMW E39 (1)

nalaleah53 · Apr 2, 2013

1998 528i battery drain update

Since my post last week, I continue to read mostly great comments and DIY posts, but I have not identified the drain source. I have a bunch of related questions
1. Why do I need to take the battery out to charge it? If I disconnect the the cables and charge it with the deck lid open is it really a risk?
2. I disconnected the battery to disconnect my FSU. Since some people advise against the difficulty of checking the fuse and said removing it was easy, have I accomplished the same thing when I check for amp drain?
3. Does disconnecting and reconnecting the battery trigger a longer time until I can measure the asleep drain?
4. Does leaving the deck lid unlatched /slightly ajar still energize the courtesy lamp circuit?
5. When I tried to measure the voltage across each fuse, I couldn't get a stable reading. Lots of .1-.3 milli volts. Is that accurate enough to say that fuse is OK? What kindf of magnitude is a suspect voltage reading?
6. Can anyone explain why my car has no fuses under the cabin filter? All slots were empty (and reconnecting that 15 year old oval seal air line wasted some time)
7. Since my amp drain didn't go down after unplugging the FSU, does that mean it's not the problem? (duh?). I didn't yet pull the FSU out, because it's hard to depress the tab and pull in that space.
8. All the OBC stories and pictures show a display like "13.7 volts" during test "9". I only get "137" Is it really displaying volts when it doesn't say it?
9. Does my "valet secondary key" unlock the deck lid if the battery is out or disconnected?
I don't expect that anyone knows all the answers to these 1998 528i questions but I welcome any further help on any of them.

bluebee · Apr 2, 2013

nalaleah53 said:
1. Why do I need to take the battery out to charge it? If I disconnect the the cables and charge it with the deck lid open is it really a risk?

Most people charge the battery from the engine bay, but many charge it from the open trunk - and some even follow BMW directions and remove it from the vehicle.

It's all about ameliorating the risks of exploding the outgassing of hydrogen and frying sensitive internal components.

This thread bemoans the risk, for example, of frying the sensitive electronics:
- One users experience debugging a half-dead instrument cluster (1)

nalaleah53 said:
I disconnected the battery to disconnect my FSU. Since some people advise against the difficulty of checking the fuse and said removing it was easy, have I accomplished the same thing when I check for amp drain?

Huh?

Are you asking if disconnecting the FSU is the same as disconnecting Fuse F76 for the purpose of stopping the overnight current drain?

If that's the question, the answer is yes (from a pragmatic perspective).
Do whichever you feel is easiest for you (both are a pain, IMHO).
- What's the secret to removing FSU blower motor fuse F76 (1)

Note: It's not exactly the same - but it's close enough.

nalaleah53 said:
3. Does disconnecting and reconnecting the battery trigger a longer time until I can measure the asleep drain?

Again, I'm confused by the question.

If you're asking about the sleep time, you already know it's 16 minutes as long as nothing happens.
Each time you "do something" (like reconnect the battery or pull & then put back certain fuses), the potential to wake up the computer occurs.
Then, the theory goes, you have to wait the 16 minutes again. In practice, that would drive you crazy, so, you'll figure out a better way.

nalaleah53 said:
4. Does leaving the deck lid unlatched /slightly ajar still energize the courtesy lamp circuit?

Ummm.... depends on how ajar it is.
But why even ask that question?

If you "really" want certain bulbs not to light, you can just pull the bulbs - or - do what everyone else does.
Just leave the trunk open for 16 minutes.
This is covered in the thread on how to check for parasitic drain.
- The most often recommended method to diagnose overnight parasitic battery current drain including the FSU (1)

Note: Maybe I'm not understanding the question - so - if that's the case, others can answer it better. I'm ready to go to bed anyway ...

nalaleah53 said:
5. When I tried to measure the voltage across each fuse, I couldn't get a stable reading. Lots of .1-.3 milli volts. Is that accurate enough to say that fuse is OK? What kindf of magnitude is a suspect voltage reading?

If you can't get a stable reading, that means the voltage is fluctuating. If the magnitude of the fluctuation is small compared to the expected readings, I'd ignore them. If it's big compared to the expected reading, then it indicates something going on.
For example, look at what happened when I measured hugely fluctuating current recently (with a BAD FSU in place):
http://youtu.be/RzVRU69xa0A

For your expected mv reading, the reference I gave you has a CHART of millivolts to expect for each fuse based on the amperage of the fuse.
So, it really depends on which fuse you were looking at (and comparing the expected reading against the chart).

nalaleah53 said:
6. Can anyone explain why my car has no fuses under the cabin filter? All slots were empty (and reconnecting that 15 year old oval seal air line wasted some time)

Hmmm.... methinks you "do" have fuses EF1 to EF5 (if your car has a working DME, oxygen sensor, MAF, Fuel Pump, ICV, etc.).

You're just not looking at the right spot. Gory details here:
- One user's attempt at locating and snapping a picture of every single fuse & relay in the BMW E39 (1)
Maybe you need to snap a picture and show it to us.

nalaleah53 said:
7. Since my amp drain didn't go down after unplugging the FSU, does that mean it's not the problem? (duh?). I didn't yet pull the FSU out, because it's hard to depress the tab and pull in that space.

If you unplugged the five-pin FSU harness connector, there are no other electrical connections to the FSU.
But, 99% of the time it's the FSU - so - I'd doublecheck that you really unplugged the right thing. Maybe snap a picture and show it to us.

nalaleah53 said:
All the OBC stories and pictures show a display like "13.7 volts" during test "9". I only get "137" Is it really displaying volts when it doesn't say it?

My cluster (high) shows this when the battery is bad:

nalaleah53 said:
9. Does my "valet secondary key" unlock the deck lid if the battery is out or disconnected?

I'll leave that for the key threads.
- A description from QSilver7 of the various types of BMW Remote, Illuminated, Spare/Wallet, & Valet/Service keys (1) (2)

nalaleah53 · Apr 7, 2013

1998 528i battery drain update NEWER

Still no smoking gun for my .22 amp drain. Just in case my question about not finding any fuses under the passenger side cabin filter caused confusion, here's a picture. If someone can say, "the fuses in there, aren't color coded and don't look anything like the instrument panel or trunk fuses", here's what "mine" look like (or not).
I'm also attempting to show a "OBC test #9 alternator and a battery voltage display. Does anyone else's display look like this without the word "volts" and a number like 13.5 with a decimal point showing? Am I really not doing a voltage test even though I drop it into test #9?

Obviously I'm frustrated I haven't found the drain after unplugging the radio, sub woofer, FSU and the aux fan. Are the fuses under the seat the only leading choices now?

rdl · Apr 8, 2013

nalaleah53 said:
Still no smoking gun for my .22 amp drain. Just in case my question about not finding any fuses under the passenger side cabin filter caused confusion, here's a picture. If someone can say, "the fuses in there, aren't color coded and don't look anything like the instrument panel or trunk fuses", here's what "mine" look like (or not).
I'm also attempting to show a "OBC test #9 alternator and a battery voltage display. Does anyone else's display look like this without the word "volts" and a number like 13.5 with a decimal point showing? Am I really not doing a voltage test even though I drop it into test #9?

Obviously I'm frustrated I haven't found the drain after unplugging the radio, sub woofer, FSU and the aux fan. Are the fuses under the seat the only leading choices now?

I've not changed these E-box fuses myself. However based on WDS locator images and pictures in other threads, you have found the 5 fuses in question. The cap with the numbering will pop off & expose the fuses more clearly. Again based on pictures in other threads, they appear to be ATO shape/configuration/size fuses, i.e. same as fuses # 1 - 45 in the glovebox.

Regards test #9 - you have the "low" or Kombi instrument cluster; same as mine. The test 9 display is exactly like mine. Your pictures are indicating a voltage of 11.1 volts.

The fuses under the passenger seat supply other circuits and components that are easier to access and check than the fuses themselves.
According to WDS for your 1998 model year these fuses supply circuits as follows:
107 - secondary air relay in Ebox (WDS locator image below)
108 - motor relay in Ebox (WDS locator image below)
109 - Ebox Fuse1 (not glovebox F1) and DME relay in Ebox (WDS locator image below)
110 - approximately 17 fuses of 1 through 45 in glovebox
111 - ignition switch
112 - light control module (LCM)
113 - LCM and several fuses in glovebox plus in some cars a "closed-circuit current cutout relay" which then feeds a fuse in glovebox
114 - ignition switch and diagnostic plug

EDIT: fuse 108 "motor relay" supplies ASC or DSC

bluebee · Apr 8, 2013

rdl said:
According to WDS for your 1998 model year these fuses supply circuits as follows

I added this excellent information to the canonical E39 fuse thread as follows:

bluebee said:
EDIT: Added better descriptions for F107 to F114 by rdl on 4/8/2013.

UNDER PASSENGER SEAT: (see more details in this thread & this thread)
F107 = 50A, SAS airpump Special Fuse: BMW PN 6113836590 (rdl says it's the secondary air relay fuse)
F108 = ??A, [QSilver7 says this is for the ABS/DSC control unit] (rdl says it's the "motor relay") (rdl clarifies that the F108 "motor relay" fuse supplies ASC or DSC)
F109 = ??A, [QSilver7 says this is for the DME (motor electronics)] (rdl says it fuses the Ebox EF1 and the DME relay in the ebox)
F110 = 80A, Power supply F1-F12 and F22-F26 (rdl says this fuses about 17 fuses, up to F45) found in the glovebox)
F111 = 50A, Data link connector/ Ignition switch (rdl confirms this is the ignition switch fuse)
F112 = 80A, Light control module (rdl confirms this is the LCM fuse)
F113 = 80A, Power supply F13 and F27-F30/ Light Module (rdl says it fuses the LCM and several fuses in glovebox plus in some cars a "closed-circuit current cutout relay" which then feeds a fuse in glovebox)
F114 = 50A, Data link connector/ Ignition switch (rdl confirms this is for the ignition switch and diagnostic plug)

I still have questions about the AMPERAGE of some of these fuses though:

F105 = ?A
F108 = ??A
F109 = ??A

Does anyone know the amperage of these three fuses?

rdl · Apr 9, 2013

bluebee said:
I added this excellent information to the canonical E39 fuse thread as follows:

I still have questions about the AMPERAGE of some of these fuses though:

F105 = ?A

F108 = ??A

F109 = ??A

Does anyone know the amperage of these three fuses?

For my 2003 530
F105 is 100 A
F108 is 50 A
F109 is 80 A
I haven't checked exhaustively for various engines, model years, etc. but spot checks found all variants are as listed above.

Regards difference in fuse circuits between myself and QSilver7 - would be due to the differences between model year, engine, etc.

528 i baseline current draw BAttery drain/ current draw

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