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**Registered From: Staffordshire, UK
2003 SLK230
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28 Posts
I was curious if you are using "u" for micro as the alphabet is not as on a PC and that explains in details the question of yours.
Just, when I see zeroes and mAmp I am sure it is not that small of a value, as no "widely" used amp meter is able to measure microAmp while most of them will show miliAmp, depending the class of the units 2 or 3 digits after the decimal dot.
I must admit, I am curious, what kind of job you have, that will "kill" if the 30microA goes up to 0.001A? Is it genetic/molecular stimulation of ... small green organisms that came from deep space or...;)
Sorry guys, I didn't mean to be rude, I really just want to be helpful to others who tread this way. Hopefully this attachment will clear things up regarding what I'm seeing on the meter. I've checked it on two other meters and get the same results across both ranges. The battery is still holding its charge after 48hours at 13.4volts though I expect it should drop back into the 12volts range in the next day or two. All comments welcome. Thanks for all your help with this. Cheers.
Measuring instrument Electrical wiring Gadget Gas Audio equipment
Light Motor vehicle Line Electrical wiring Measuring instrument

I believe @Geoff Campbell is satisfied with the 20-40miliAmps after all the sweat and readings for the moment, but polite enough to not request "closure" of this otherwise "endless" fountain of knowledge! Wide and unexpected in computer science, applicable math, measuring of otherwise unneeded µ values, etc.
Geoff my 1998 230K somehow keeps the electronics "alive" if I use my key to unlock and open the trunk, after it is closed and locked (key, not remote) it still holds 80-100mAmps. So if once the remote is used (as per my experience) mechanical interventions do not reach that state of "rest" we all need to keep the batteries in healthy condition. Just on a good to know basis!
OK, so can I clarify, are you saying that if you unlock and open the trunk and then close and lock it both using the key, the locking circuitry across the car stays awake and draws this higher current? If I've got that correctly, does locking via the remote return the system to the lower current draw?
 

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*Registered
2014 SLK250
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377 Posts
Whoa! Holy electrons Batman!
so it is 0 . 0 2 m A (on the mA scale)
that sure looks like 20uA … which is practically no draw
glad you posted the pic!

OK … now all the car wizzes can explain the 3 orders of magnitude drop from common draws

I will presume the probe tips have a well established contact (thru oxidation crud etc) and the reading is still practically nothing

However all that said a change to a different probe current port shows 0.2A (on the A scale) so back to the 200mA draw again ( more realistic? )

Something fishy with the multimeter internal impedance or reference??
 

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*Registered
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641 Posts
OK, so can I clarify, are you saying that if you unlock and open the trunk and then close and lock it both using the key, the locking circuitry across the car stays awake and draws this higher current? If I've got that correctly, does locking via the remote return the system to the lower current draw?
Yes!
Exactly.
I remember sharing this in the (I think) what did you do ... but it was 2020 I think.
And yes using the remote it sets the "sleep" mode to 0.0*Amp.
Again you have found some pretty cool measuring device with microAmp "scale" that is very, very good device.
And if, like @ndevonn mentioned, you see a battery symbol on screen, replace the battery of the measuring tool, so you can be sure it is not a "low voltage ghost" messing with the readings.
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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8,093 Posts
that is very, very good device.
I agree ...........

IF it is actually reading correctly ..........

I tend to agree with @ndevonn there is something very fishy going on !!

@Geoff Campbell I am not familiar with your meter, I use FLUKE, but is it possible your A and mA measurements are on AC Scale rather than DC ..............

I mean your meter, (just above red elastic band, 3rd button from left has AC and DC Symbols could this be why the oddball readings ?

Perhaps try pressing that button and see if you get some more intelligeable readings, if you had 0.200 Amp drain Battery would be dropping Voltage like a stone off a tall building ;)

The other thing I see here is you holding the probe onto the battery terminal, are you actually standing there for 10 - 20 mins + to observe the Car going to sleep ?

I always use a Crock Clip on both sides, if your not allowing time elapse then the readings will start high but should actually drop off over the 10 - 30 minute interval (actual elapsed time is Car Spec dependent).
 

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*Premium Member
2005 SLK200K 'Little Growler'
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2,480 Posts
Okay, let’s see if I’ve got this right. Buy new battery for meter. Open the bonnet and then lock car using fob. Remove negative terminal from battery. Connect meter with crocodile clips between negative terminal of the battery and negative lead. Look at the reading every five minutes for half an hour. Find out what kind of parasitic drain you’ve got?
 

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*Registered
2014 SLK250
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377 Posts
the ac dc selector could be a culprit in the incongruent results … per the user manual perhaps toggling it may be revealing in terms of measurement integrity
though the meter’s internal reference resistance for 0-300mA and 0-10A would have to be rather different in terms of converting the related voltage drop to a current reading
and then the dynamic range and nonlinearity will come into play etc etc the usual measurement instrument hoohah
ideally we should see say 200mA on the mA scale and 0.2A on the A scale presuming the instrument has been properly calibrated over the nonlinearity segments of the transfer functions for the particular sensing circuits and so forth

anyway … am inclined to see the 200mA draw as the realistic result?
especially if the “ac” vs “dc” mode results are variant

kinda miss my old fashioned sanwa and simpson meters
 

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*Premium Member
2005 SLK200K 'Little Growler'
Joined
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2,480 Posts
the ac dc selector could be a culprit in the incongruent results … per the user manual perhaps toggling it may be revealing in terms of measurement integrity
though the meter’s internal reference resistance for 0-300mA and 0-10A would have to be rather different in terms of converting the related voltage drop to a current reading
and then the dynamic range and nonlinearity will come into play etc etc the usual measurement instrument hoohah
ideally we should see say 200mA on the mA scale and 0.2A on the A scale presuming the instrument has been properly calibrated over the nonlinearity segments of the transfer functions for the particular sensing circuits and so forth

anyway … am inclined to see the 200mA draw as the realistic result?
especially if the “ac” vs “dc” mode results are variant

kinda miss my old fashioned sanwa and simpson meters
Now don’t go confusing me 🤷🏼‍♂️ 😂
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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8,093 Posts
Okay, let’s see if I’ve got this right. Buy new battery for meter. Open the bonnet and then lock car using fob.
Sort of, but you've not thought how the car thinks and what it needs to see to shut down properly.
Whoever is doing this job needs to be fully conversant with how the Car works ;)

For example lock the bonnet latch with bonnet up (R170 ) or put a cable tie / elastic band around the bonnet pin switch (that VXR Astra),...............

Also you may need to get in and outta the car for testing, so I leave whatever door(s) open but fasten their locks and clamp down any pin switches ....................

And then if you have a drain and need to start un coupling wires or pulling fuses, a lot of times the meter will spike up, then you have to wait before the next test to allow the Car back to sleep mode ..............................

This is why I charge what I charge by the hour, it can take all day ++++ in some cases to find a current drain ...................

There are ways to speed it up, but it is hellish to explain and I don't got time to go into all that, but very basically I split the car into sub sections, by removing main power from each and every fuse box one at a time so pull the power from each one of them one at a time and if drain goes that's the area to concentrate on ;)

Wait until you get a car with several drains due to water ingress ................. 39 hours to fully sort one of 'em a while back, car was only worth twice that cost ;)
 

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**Premium Member '02 R170 SLK V8 5.0 & '00 SLK320
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8,093 Posts

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*Premium Member
2005 SLK200K 'Little Growler'
Joined
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2,480 Posts
Sort of, but you've not thought how the car thinks and what it needs to see to shut down properly.
Whoever is doing this job needs to be fully conversant with how the Car works ;)

For example lock the bonnet latch with bonnet up (R170 ) or put a cable tie / elastic band around the bonnet pin switch (that VXR Astra),...............

Also you may need to get in and outta the car for testing, so I leave whatever door(s) open but fasten their locks and clamp down any pin switches ....................

And then if you have a drain and need to start un coupling wires or pulling fuses, a lot of times the meter will spike up, then you have to wait before the next test to allow the Car back to sleep mode ..............................

This is why I charge what I charge by the hour, it can take all day ++++ in some cases to find a current drain ...................

There are ways to speed it up, but it is hellish to explain and I don't got time to go into all that, but very basically I split the car into sub sections, by removing main power from each and every fuse box one at a time so pull the power from each one of them one at a time and if drain goes that's the area to concentrate on ;)

Wait until you get a car with several drains due to water ingress ................. 39 hours to fully sort one of 'em a while back, car was only worth twice that cost ;)
I get you Dave. I don’t know that I have have a drain, I’m just intrigued to see how many milliamps are getting pulled when the car is not running. I think I’ll just leave a window open and close the bonnet it the meter’s leads are long enough.
 

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*Registered
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641 Posts
I don’t know that I have have a drain, I’m just intrigued to see how many milliamps are getting pulled when the car is not running. I think I’ll just leave a window open and close the bonnet it the meter’s leads are long enough.
I will add some "spam"!
The attached are after I fixed some issues and before dropping new Battery:
Green Motor vehicle Electrical wiring Gauge Line
Motor vehicle Electrical wiring Cable Auto part Automotive exterior
Motor vehicle Gas Gadget Communication Device Electrical wiring
Light Electrical wiring Motor vehicle Gas Measuring instrument
Vehicle Odometer Speedometer Trip computer Gauge

The names are the actual date time picture's taken.
I explained about the boot being unlocked by key and later closed and locked - the consumption was still HIGH - I can't point the exact "drain" but there are few shots!
Last one and the one before the last one are exactly what I was hoping to find 20-25mAmp.
0.027A is with 2-3 leads more (not gravity "plugs" like the second to last pic), so the bonnet is closed, no wirings "touching" and the car was locked with the remote.
And my multi-meter do select by itself AUTOmatically (between AC and DC), just as I had company one that was on auto and didn't switch to anything but DC. And this way the AC/DC button errors are "less" plausible.
I haven't checked it with my new-er battery...aug '20 isn't exactly new, but I have not felt disturbing forces and...do not repair if ain't broken sounds good to me.
 
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