Help. Parasitic draw is killing my battery

[eanoca01]

Hi

I'm having an issue with my 2010 Superb Elegance. After a day or two my battery which is less than 2 months old is dead to the point that it won't start the car.
I have checked the current draw on the battery, and it is about a ~1.3A draw. I did ensure that everything was shut down, car was off for 2 hours, doors locked etc, before testing.
I tested each fuse under the bonnet, and on the driver side dash, as mine is a RHD model.  My findings were as follows:

 

F6 -> 0.33A draw

F8 -> 0.12A draw

F9 -> 0.1A draw

F12 0.12A draw

F19 -> 0.03A draw

F29 -> 0.2A draw

 

These all don't still add up to the 1.3A total draw I measured. So I'm at a bit of a loss. 

 

1. Any ideas on what I do for about the above circuits? Any tip on fixing these? And why so many?

2. I've checked every fuse and they don't add up to the total, am I missing something?

Thanks in advance for any help.
 

[Breezy_Pete]

Engine code needed in order to find appropriate wiring info.

[eanoca01]

Unfortunately the sticker in the boot is worn to the stage that it cannot be made out. And I don't have a service book for it. Is it possible to get the code by any other means? Via the VIN number or anything?

[Breezy_Pete]

Look for a sticker on the upper cambelt cover, that will have it at the start of the engine number if you have such a sticker.

[SuperbTWM]

I take it you calculated the current by measuring the voltage drop across the fuses rather than pulling them out? 

 

 

[eanoca01]

Quote

Look for a sticker on the upper cambelt cover, that will have it at the start of the engine number if you have such a sticker.

 

Ok yes this exists for me, code seems to be CBB

 

Quote

I take it you calculated the current by measuring the voltage drop across the fuses rather than pulling them out? 

Afraid not, I measured by checking the total draw when pulling each fuse out one by one. Is this a less effective method?
 

[SuperbTWM]

5 minutes ago, eanoca01 said:

 

Is this a less effective method?
 

 

Yes, its a bit pointless really as pulling a fuse and then measuring the current re-powers any electronics or modules on that circuit giving you a higher than normal reading.

 

You were right in making sure the car thinks all the doors and bonnet are locked by frigging the locks, you want to turn off any interior alarms and lock the car for a while and wait for everything to go to 'sleep'

 

Then measure on a mV scale across all the fuses with a reliable multimeter. There is a document explaining this somewhere which I will try and dig out.

 

https://forums.tdiclub.com/index.php?threads/tsb-and-matrix-for-battery-drain-issues.254875/

 

Use the tables at the back to work out current draw from the voltage drop and the size of fuse you were measuring.

 

Good luck

Edited 2 March, 2021 by SuperbTWM

[Breezy_Pete]

What he ^ says is great advice. 

Turns out that none of the fuses you list seem to be engine-related so that info may not have been essential after all.  

Is the radio the factory original? Any tinkering in that area is usually a prime suspect.

[SuperbTWM]

Or a pesky bypass relay for tow bar electrics maybe?

[Roots Supercharger]

Is your Superb a MK11 Twindoor? I have just repaired the wiring to the boot at the LHS boot hinge of my 2009 Mk11Twindoor. About 5 wires were bare and/or broken.

I had a fluctuating parasitic drain of 1.5 to 12 amps. The wiring at the boot hinge is a well known problem and I now only open the back as a hatch.

[pdrisc]

I have a similar issue with my car. Its a 58 plate car but in a separate thread someone has commented that they think it may be a body control module issue. My issue is the rear lights on the drivers side and the number plate lights remain on. For the last 2 mornings the car has been flat so i have had to take a boost from another car. 

I have used a simple code reader which says there is an earth fault but i have arranged to go to a friendly garage and get them to read it and hopefully reset it on Friday.

 

i am going to be replacing it soon so just need it to get over the garage forecourt. Changing to an L&K superb 3. (more stuff to go wrong?)

[superbdreams]

I bought a logging dc clamp meter (bluetooth) very cheap from amazon when i had what i thought was a parasitic drain for years from new.

I Didn't need the meter in the end but could help others to know of them.

[eanoca01]

So...

Quote

Then measure on a mV scale across all the fuses with a reliable multimeter. There is a document explaining this somewhere which I will try and dig out.

 

I did this, and every single fuse was zero when the car had been powered off for more than 2 hours. My multimeter is working fine I believe, as I turned the car on, and checked the voltage across the heated seat circuit for example, and I could see the voltage increase when I turned it on, just as a test for the meter.

So I'm a bit stumped as to what's draining my battery now.

 

Quote

Is your Superb a MK11 Twindoor? I have just repaired the wiring to the boot at the LHS boot hinge of my 2009 Mk11Twindoor. About 5 wires were bare and/or broken.

I had a fluctuating parasitic drain of 1.5 to 12 amps. The wiring at the boot hinge is a well known problem and I now only open the back as a hatch.

 

Yes its the twin door, but the hatchback mode never worked for me, the handle to engage this mode doesn't seem to do anything. I believe the brake lights on the rear window should come on as soon as you press this, but they don't seem to.

[Roots Supercharger]

Hatch not opening is one indication that there is a problem with the LHS boot hinge wiring.

Read the helpful Briskoda  how to guide 'Skoda Superb Guides' under the heading of 'Superb Twin Door Wiring Fix', I think it might help you.                                                                                                   

[SuperbTWM]

4 hours ago, eanoca01 said:

So...

 

I did this, and every single fuse was zero when the car had been powered off for more than 2 hours. My multimeter is working fine I believe, as I turned the car on, and checked the voltage across the heated seat circuit for example, and I could see the voltage increase when I turned it on, just as a test for the meter.

So I'm a bit stumped as to what's draining my battery now.

 

 

Yes its the twin door, but the hatchback mode never worked for me, the handle to engage this mode doesn't seem to do anything. I believe the brake lights on the rear window should come on as soon as you press this, but they don't seem to.

 

You could be looking for a reading in the region of a few mV down to tenths of mV. What multimeter do you have?

[Breezy_Pete]

When you say every single fuse, do you include the ones in the cabin?

[eanoca01]

6 hours ago, SuperbTWM said:

 

You could be looking for a reading in the region of a few mV down to tenths of mV. What multimeter do you have?

This one here : 
https://www.diy.com/departments/digital-0-600v-multimeter/541252_BQ.prd

 

5 hours ago, Wino said:

When you say every single fuse, do you include the ones in the cabin?

 Yes including the cabin fuse board

[SuperbTWM]

I don’t think you can expect that multimeter to be reliable at voltages so low. You need something a bit more upmarket for this method to work. There must be some circuits in there using power

[J.R.]

It has a 200 millivolt DC range so will be perfectly up to the job, sure you could buy better for the money but there is no point discarding that one.

[SuperbTWM]

Problem with cheap meters is you can’t trust them and can start second guessing them  
 

We have a situation where he’s not measuring any voltage across any of the fuses. So it’s either user error, there is no parasitic draw, or the meter is pants. 
 
might be easier to just pull the fuse for the radio and leave it a week see if that sorts it, and if not work through the rest of the circuits

 

 

[J.R.]

Point taken, I agree!

 

Probably on the wrong range.

[KiwiBen]

Hi'

I had this problem a couple of years back and after exhaustive testing of fuses, current draws and eventually voltage drops, found the problem to be corroded circuits under the seat swiches for the drivers 'comfort' seat. This didnt show up in the tests because the seat is not fused; it has a self resetting CB! 

Now I have the same problem again and still no joy. I'd been told that radios are a known problem so pulled fuse F8 in the engine bay which is listed as RADIO but it pulls power from everything except internal lights, door locks and ciggy lighters!! Any oegot any suggestions??