What is causing this drain?

[amwebby]

Twice now over the holidays I've had to call out MobiloLife for a flat battery (new one year ago).

Something is draining the battery but what? I have three possibilities:


UHI Kit, retrofitted by myself with expert advice and the least likely as fitted for two months now.
TV Tuner - as the car was pre-wired, with the exception of the amplifiers, unlikely as it should have been plug and play.
Third party DVD/MP3 player. Most likely as just fitted, but by a professional installer. Unit goes off with ignition. One possibility was the USB input, a memory stick in there may have been draining when off but no light was showing from the stick when ignition off.Ideas please. I've disabled the DVD player until I can get it checked and I can see it is the most likely but why? If the unit powers down when the ignition is off there should be no drain, right?

[television]

The max current allowable is 38m/a when the car is locked.

This can only be checked by inserting an ammeter without breaking the circuit so that the path of the leak is not broken

[amwebby]

MobiloLife checked by some device that encircled the live feed from the battery. They said it should show no more that 0.08 amps. The closed the boot lock and locked the car to fool the car into thinking it was fully closed and shut down. It got down to about 0.18-0.20 after around 15 minutes.

[television]

MobiloLife checked by some device that encircled the live feed from the battery. They said it should show no more that 0.08 amps. The closed the boot lock and locked the car to fool the car into thniking it was fully closed and shut down. It got down to about 0.18-0.20 after around 15 minutes.

I hope you mean 0.018 -0.020 if not then something is drawing too much.

The device they used was a clamp meter

The figure of 0.080 is an outside max when they have problem cars but 0.038 is the correct max when perfect and locked

[amwebby]

They said about a quarter of an amp. So something is draining it.

[television]

They said about a quarter of an amp. So something is draining it.

The Comand is one of the biggest reasons,it is quite simple to withdraw the fuse for this and pop an ammeter over the two contacts, this will cover all items on that circuit.

Another is the OCP

I have the Comand problem, so I modified the shut down circuit

[amwebby]

The MobiloLife technician mentioned COMAND as the most likely culprit. Why should it suddenly start doing this though, unless adding the TV caused it?

[Diesel Benz]

I don't know anything about an SL but just happened to read about an incorrect relay installed on the additional fan, causing an additional current drain of 0.2 amps, this figure just goes with the figures measured from the car.

I believe my clamp meter would be able to detect this current level without uninstalling the battery cable, would just need to remove the fuse for the additional fan.

[Diesel Benz]

The MobiloLife technician mentioned COMAND as the most likely culprit. Why should it suddenly start doing this though, unless adding the TV caused it?

Again, don't know but there were several posts on other cars about the equipment on the CAN, the same one Comand would be using and any of those could cause Comand not going to sleep (of course an issue at the Comand unit itself too).

But taking fuses out one by one should help diagnosing (although the one taken off might help the faulty one go to sleep).

[television]

I don't know anything about an SL but just happened to read about an incorrect relay installed on the additional fan, causing an additional current drain of 0.2 amps, this figure just goes with the figures measured from the car.

I believe my clamp meter would be able to detect this current level without uninstalling the battery cable, would just need to remove the fuse for the additional fan.


I think that this fan is the OCP one that affects the Comand

[Diesel Benz]

I have the Comand problem, so I modified the shut down circuit

Don't they have any SW update solution? If it is HW, I would expect a new device as it is a design flaw?

[Diesel Benz]

I think that this fan is the OCP one that affects the Comand

I guess that fan could be an issue or the OCP panel itself but the document I was reading was really about the additional fan, covered by F42 to on the right fuse and relay box (I just happened to read about it, don't have any experience).

[amwebby]

That fits in with my theory, that the feed to the DVD unit is somehow at fault. I've withdrawn the power supply to the unit at the back but sadly I don't own a clamp meter.

[television]

Don't they have any SW update solution? If it is HW, I would expect a new device as it is a design flaw?

Up till recently there has been no one that would repair these things, but there are firms now that are starting to do work on them.

MB have been quite happily taking a few grand for replacements.

[television]

That fits in with my theory, that the feed to the DVD unit is somehow at fault. I've withdrawn the power supply to the unit at the back but sadly I don't own a clamp meter.

Before I modified mine the CD changer would keep trying to load until the battery cut off when it got down to 11.7 volt.

CPC have a meter with a fuse plug on the leads, and you just plug this in in place of the fuse to get an instant read out of up to 20 amps, they cost about £6 + VAT.

A clamp meter would cost around £300 to measure DC down to 20m/a

[amwebby]

Cpc?

[television]

Cpc?


www.cpc.co.uk part number IN04874 £6.95

they have been on special offer.

you could use a normal multi meter with if you have one with leads, part number IN04873

[amwebby]

Thanks Television. Now, where are the fuses?

[television]

Thanks Television. Now, where are the fuses?


You will have to wait for that one as your car is not the same as mine

Roughly you will find here. I can post back later in the day, I need to go and earn some money.. there should be a fuse layout in the tool kit

062,080,084,089

http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=215375&M=113%2E960&GA=722%2E633&CT=F&Cat=65N&SID=54

[Diesel Benz]

Just had another look at CL500 issues. There is a Comand SW update from 2004, perhaps this car is newer and then this update should not apply. Then there is a huge list of VINs for cars with a Comand unit where the only cure is to replace the unit. I assume you don't want to give the VIN but the list is also for Comand serial numbers. Could check, or send the document (unless you also have it).

[Diesel Benz]

The Comand is one of the biggest reasons,it is quite simple to withdraw the fuse for this and pop an ammeter over the two contacts, this will cover all items on that circuit.

Another is the OCP

I have the Comand problem, so I modified the shut down circuit

I'm stealing the thread a bit but I also browsed some SL500 documents. I wonder if you were aware of (and interested about) a couple of instrument cluster related cases that cause increased quiescent current. The only cure would anyway be a new IC, interesting that you were able to fix it with a modified circuitry, MB might have been interested about the fix (although they prefer not changing wiring).

Anyway, the first issue only appears when a phone kit is in use and a phone in the cradle or BT device, and PIN code request is active. The other one is just a SW error on the IC resulting to faulty communication between the IC and the head unit. This applies for a dozen different head unit part numbers.

[amwebby]

Just had another look at CL500 issues. There is a Comand SW update from 2004, perhaps this car is newer and then this update should not apply. Then there is a huge list of VINs for cars with a Comand unit where the only cure is to replace the unit. I assume you don't want to give the VIN but the list is also for Comand serial numbers. Could check, or send the document (unless you also have it).
Mine is a 2000 model. I don't have the list so would appreciate that.

[R/T.E49]

I've got that disc...or at least the 07/2002 one. Stops the cd motor from running on causing a battery drain. It's just a SW update that goes straight in the comand.

[television]

My mod uses a timer module ( £13) and a further relay, its simple to add the timer by just plugging into the fuse holder, and actuating the timer from the fuel pump relay so that when you start the car the comand is actuated and it will run for 30 mins then stop,if the ignition was turned off, but runs the whole time when the ign is on. if I am watching TV and it stops, then flicking the key to 2 and off again starts the process again. I could make it run for up to 2 hours if I wished

It was easy in my car as everything is behind the back seat

[amwebby]

Well I've checked all the documents. None of them refer to my COMAND unit and I have applied the software update (although with a slightly different disc no. Mine is A230 589 00 22 00 and the docs say you should use A215 589 00 22 00).

I have heard the TV Tuner can cause this kind of drain. Anyone heard of this?

[richard]

Well I've checked all the documents. None of them refer to my COMAND unit and I have applied the software update (although with a slightly different disc no. Mine is A230 589 00 22 00 and the docs say you should use A215 589 00 22 00).

I have heard the TV Tuner can cause this kind of drain. Anyone heard of this?

A230 xxx is just a later release than the A215 xxx and A220 xxx part disks

Cheers

R

[Diesel Benz]

I'm hoping ideas from those who have knowledge and experience with this car but just "from the computer" I only find one issue really for the whole 82.60 group, this concerning the TV tuner but I understand that the issue only appears as a persistent fault code. There is a reference to WIS document AF82.60-P-8400A, I did not have a look but assume this would not cause increased quiescent current.

Did you actually get to the fuses to figure out which control unit is drawing current? Also WIS document SI54-10-P-0016A describes the current if you just measure the voltage drop over the fuse (could be more accurate in case removing one fuse makes another, possibly faulty unit go to sleep).

By the way, one of the documents should have mentioned the part number W230589002200 (for some reason, a later document has a lower document number).

[television]

If you are going to measure the resistance the battery must be disconnected and that does look a novel way to go about it.

Just as a side issue, if the drain stops with the Comand fuse pulled, as I cant work on my car in the garage, and when its to cold or wet to be outside, I fitted a switch on an extension lead under my seat to turn it off when parked up.

In the spring I will see what the exact fault is on mine, just for the learning curve and what goes wrong.

[amwebby]

I haven't received my ammeter yet so haven't had chance to measure the fuses.

I can't find that WIS document either. In fact so far I've found nothing is WIS beyond the stored fault document.

[BfromH]

Just to clarify, The document posted by Diesel Benz is telling you the cold resistance of the FUSES. Without breaking the circuit (by removing the fuse) you can still use a sensitive voltmeter to see if there is a small voltage drop across the fuse.
No drop = no current, small drop = small current,
At Rated current (e.g. 30A) the fuse will drop up to about 0.1V before it's rising resistance and volt drop cause it's temperature to rise and 'blowing' at 1.5 to 2X rating

The advantage of this is that you don't need to break the circuit to look for leakage. The bad news is that the voltage drop across a 30 A fuse where the circuit is taking just 56mA will be 100 uV that's microvolts (0.0001V). Like I said a sensitive meter.
And a lot of work to check every circuit.
Very useful if a particular suspect needs checking though.

As everyone has said the 'ideal' process is to let the car go to sleep, connect a quality autoranging ammeter, (set to mA with the plugs in the right holes for a range that can stand 500mA) FIRMLY between the actual battery post and the battery lead.

Or get a steady handed helper to hold the meter leads in place, but even a momentary break will mess everything up..... 2 person job for sure if using this approach.

Then remove the battery lead from battery post, leaving one meter lead on each side of the 'gap' so the residual/leakage current must flow through the meter, take reading, reconnect battery lead. Technically the positive or negative lead will be equally good. Practically there is much much less risk from it all going awry if the negative is chosen.

If there was a large residual current then try the above approach to isolate the culprit. If not pursue the insufficient charging, dud battery line of attack. I have always found the best approach is to start by replacing any battery over 24 months old before any faffing with chargers, Ammeters etc. This avoids putting hours of work in before finding this cured it. depends of course on how you value your hours . . :-)

Important warning. If this is not totally familiar territory and the risks accepted DON'T DO IT. find someone who knows what they are doing.

[television]

I use a stacked lead with two leads for testing faults where the circuit must not be broken, thats one lead with a clamp and one with a probe, and just a clamp on the other one
The advantage of using the ground terminal is that you can put the single lead clamp on a ground point.- Take the probe and and place it in the center of the battery post, slacken the clamp and slide it up the probe, then put the other clamp on the battery post, and thats it.


With these leaks on the Comands it does not matter if you break the circuit as it always there

[richard]

Hi
Looking at your original post, it seems that the 2 recent changes, in reverse order are DVD player, and TV tuner. so you should look at those

Can I suggest you do the following
a) unplug the TV tuner power connector (and all others preferably if you can) - I say do this first because it is easiest for you to get to and you have played with that bit before - If this fixes it is TV tuner, or DVD player making TV tuner use more power for some reason (I dont know whether TV tuner will wake up when it has a video signal, I dont think so, but perhaps it does)
b) If this does fix it, plug TV tuner back in, and remove the connection to the DVD player (it will be the one you didnt put in when you installed the TV tuner!) If still fixed, plug it back in and see what happens. Fault should re-occur
c) If fault re-occurs its probably DVD player, so disconnect all wiring from DVD player (should plug in on back) and see what happens. DVD player may have 2 feeds - a constant and a switched feed.

Hope that helps
R

[television]

Hi
Looking at your original post, it seems that the 2 recent changes, in reverse order are DVD player, and TV tuner. so you should look at those

Can I suggest you do the following
a) unplug the TV tuner power connector (and all others preferably if you can) - I say do this first because it is easiest for you to get to and you have played with that bit before - If this fixes it is TV tuner, or DVD player making TV tuner use more power for some reason (I dont know whether TV tuner will wake up when it has a video signal, I dont think so, but perhaps it does)
b) If this does fix it, plug TV tuner back in, and remove the connection to the DVD player (it will be the one you didnt put in when you installed the TV tuner!) If still fixed, plug it back in and see what happens. Fault should re-occur
c) If fault re-occurs its probably DVD player, so disconnect all wiring from DVD player (should plug in on back) and see what happens. DVD player may have 2 feeds - a constant and a switched feed.

Hope that helps
R
I have a feeling Richard that my CD unit is the fault on mine, as it clicked and clonked, and tried to reload the whole time until the battery low turned it off.

In the spring I will double check it

[amwebby]

My thoughts are the same as yours Richard although I have approached it slightly differently,disabling the DVD player first. If there is still a battery drain then I shall try disabling the TV Tuner.

[amwebby]

The car is still away having bodywork done, with the TV tuner and DVD player disabled, but a thought has just occurred to me.

When I fitted the TV Tuner I did not have a bracket and the boot panel would not allow for one, so I just jammed it in there temporarily until I got a bracket and a new panel.

One of the attachments to the bracket is what I take to be an earth bolt from the TV unit to the bracket, which is obviously not connected at the moment.

Could this lack of earth be what is causing the drain?

[television]

The car is still away having bodywork done, with the TV tuner and DVD player disabled, but a thought has just occurred to me.

When I fitted the TV Tuner I did not have a bracket and the boot panel would not allow for one, so I just jammed it in there temporarily until I got a bracket and a new panel.

One of the attachments to the bracket is what I take to be an earth bolt from the TV unit to the bracket, which is obviously not connected at the moment.

Could this lack of earth be what is causing the drain?

If its still joined up to a live, but the drain on a tuner is no more than 30ma

[amwebby]

That's about what we had, draining the battery over 3 days or more.

[television]

That's about what we had, draining the battery over 3 days or more.

I would just unpug the live feed to it, that should fix it, as far as I can remember it is not connected via the commánd, but from the rear SAM or fuse box, so I feel that it will always be on

[amwebby]

That's what I have done for now. So you think earthing it will remove that problem?

[television]

That's what I have done for now. So you think earthing it will remove that problem?


If it is unplugged then earthing it should make no difference, these things are also grounded via the cable inter connects

[amwebby]

No, I mean when I plug it back in. It's not much use to me unplugged.

[television]

No, I mean when I plug it back in. It's not much use to me unplugged.

I do feel that where you have it connected (live) is not correct as my thoughts were that it will not turn off, The live Feed must be taken from somewhere else as it is not going to sleep

[amwebby]

It is connected via the prewiring that was in the car. But no earth as I did not have the cradle. I think that is the problem. Hence I have unplugged it iuntil I get a cradle.

[television]

It is connected via the prewiring that was in the car. But no earth as I did not have the cradle. I think that is the problem. Hence I have unplugged it iuntil I get a cradle.

OK that could be the case, good luck