Hi all,

 

I have been experiencing a lot of battery drain issues with my car. Only a few days of not being used and it's dead. Or even being used everyday (not driven particularly far) it still managed to die. 

 

I drove it for 2 hours yesterday to FULLY charge the battery (battery is new, replaced in July when the issues where first noticed). I measured the voltage with my multimeter. 12.06v as of 3pm yesterday. This morning (measured at 11:15) the voltage has already dropped to 11.75v. That CANNOT be normal. 

 

I have a black box fitted to the car but I can't imagine that is causing that much draw. What is causing this!!!

 

I took the car into a garage about a month ago to have it looked at. They replaced the passenger door loom as the wiring was damaged, I also had the radio loom wiring repaired as I noticed that it was damaged when I replaced the head unit. This has had no effect as you can see. 

 

The head unit isnt "coded" to the car? Could that be part of the issue? What other steps can I take to work this out??? 

 

The heated seats in the car haven't worked since I got it, so I removed the heated seat fuses to see if those circuits were the issue, still draining. 

 

I can't trust my car AT ALL, because it just might not start. 

 

Please help me as this has been 6 months of pain, and I've already spent almost £700 on electrical fixes that haven't done ANYTHING. 

 

 

 

Specifics of the car. 

 

Skoda Superb MKII Hatchback. 2012 Elegance model. 

 

2.0 TDI 140bhp

 

 

1 hour ago, AverageMax said:

I have been experiencing a lot of battery drain issues with my car. Only a few days of not being used and it's dead. Or even being used everyday (not driven particularly far) it still managed to die.

This might seem like a strange question, but does the battery light come on when you first switch the ignition on, and before you start the engine?

First of all, a drop from 12.06v to 11.75v in so short time indicates that you have a problem. Also, a lead acid battery, even if it is new, will probably be damaged if voltage drops under 12v. One cannot rule it out.

A fully charged and 100% working battery should measure around 12.8v. A drop in short time down to 12v might as said ndicate damage to a cell.

Well, to start measuring any drainage, I would at least start to measure current draw by checking the fuses, one by one. Hook up a multimeter that measure the current amp from yor positive terminal and while looking, remove fuse by fuse. In rest mode, the car should not drain any more than 20-25mA (0.025A). If wiring is faulty, a current draw at 2-500mA will drain out your battery in a week. And that will destroy it.

So, start with the fuses and current draw is my tip for you.

1 hour ago, rbhelle said:

First of all, a drop from 12.06v to 11.75v in so short time indicates that you have a problem. Also, a lead acid battery, even if it is new, will probably be damaged if voltage drops under 12v. One cannot rule it out.

A fully charged and 100% working battery should measure around 12.8v. A drop in short time down to 12v might as said ndicate damage to a cell.

Well, to start measuring any drainage, I would at least start to measure current draw by checking the fuses, one by one. Hook up a multimeter that measure the current amp from yor positive terminal and while looking, remove fuse by fuse. In rest mode, the car should not drain any more than 20-25mA (0.025A). If wiring is faulty, a current draw at 2-500mA will drain out your battery in a week. And that will destroy it.

So, start with the fuses and current draw is my tip for you.

 

Where should I connect the multimeter?

 

Between the battery terminal and the cable?

 

 

Thank you

Does the car have stop start fitted, was thinking the car battery should have been updated into the computer with correct software/tool ?

2 minutes ago, gav_is_con said:

Does the car have stop start fitted, was thinking the car battery should have been updated into the computer with correct software/tool ?

No engine start stop

On 03/12/2023 at 12:44, Paws4Thot said:

This might seem like a strange question, but does the battery light come on when you first switch the ignition on, and before you start the engine?

Yes it does

20 minutes ago, AverageMax said:

Yes it does

Well, that rules out issues with the alternator control wires.

On 03/12/2023 at 15:02, AverageMax said:

 

Where should I connect the multimeter?

 

Between the battery terminal and the cable?

 

 

Thank you

Oh, buy yourself a clamp Amperemeter and use around the positive cable. Then remove fuse by fuse to see when a amp drop/increase happens. Then you know what drains your power.

Just now, rbhelle said:

Oh, buy yourself a clamp Amperemeter and use around the positive cable. Then remove fuse by fuse to see when a amp drop/increase happens. Then you know what drains your power.

I have a clamp ammeter, but I don't think it is sensitive enough (only goes down to 1amp). Any recommendations on one to buy?

18 minutes ago, AverageMax said:

I have a clamp ammeter, but I don't think it is sensitive enough (only goes down to 1amp). Any recommendations on one to buy?

Well, you should try it. I have a pretty cheap one. UNI-T UT203R is mine. Search for it, not an expensive one, but does the job. Measure DCA between 0,04-400A.

I paid 45 Gbp.

6 minutes ago, rbhelle said:

Well, you should try it. I have a pretty cheap one. UNI-T UT203R is mine. Search for it, not an expensive one, but does the job. Measure DCA between 0,04-400A.

I paid 45 Gbp.

Perfect I will have a look. Mine is even cheaper haha, only does 1A - 400A. So need a better one. 

 

What SHOULD it be drawing. What is an expected value. 

On 13/01/2024 at 12:15, AverageMax said:

Perfect I will have a look. Mine is even cheaper haha, only does 1A - 400A. So need a better one. 

 

What SHOULD it be drawing. What is an expected value. 

I would say that it should not be more than 200-300 mA (0,2-0,3A) if car is in deep sleep mode.

Precondition before test is conducted: all doors closed. Open bonnet, use key to lock car. Wait 30-60min to be sure that car enters deep sleep mode. Then use clamp amperemeter on the positive cable and measure. If value is above approx 0,4-1A, well, open doors and lock car again. Or use a screwdriver to engage door locks to a "locked" position. Wait 30-60min and this time, have someone take out fuse by fuse and see when clamp amperemeter drainage drops to normal value (from 0A to 0,3A). 

9 hours ago, rbhelle said:

I would say that it should not be more than 200-300 mA (0,2-0,3A) if car is in deep sleep mode.

Precondition before test is conducted: all doors closed. Open bonnet, use key to lock car. Wait 30-60min to be sure that car enters deep sleep mode. Then use clamp amperemeter on the positive cable and measure. If value is above approx 0,4-1A, well, open doors and lock car again. Or use a screwdriver to engage door locks to a "locked" position. Wait 30-60min and this time, have someone take out fuse by fuse and see when clamp amperemeter drainage drops to normal value (from 0A to 0,3A). 

Perfect thank you. I will give it a go.

 

Any fuses most likely to cause it?

 

Or should I just do them all

Well, I would do them all. It is still a wild guess what is draining battery. If you know that you have noticed it after you installed something lately, maybe that will guide you. If nothing is done...well, do them all :-)

any more news on this subject ?

 

i also now have a bad drain on my mk 2 vrs 2012 estate using a jump pack too often ... brand new battery 100 amp bosch 

 

no new equipment fitted but did originally have tow bar removed and all its wiring tucked up under back bodywork? 

Edited 18 May, 20242 yr by promomast

1 hour ago, promomast said:

any more news on this subject ?

 

i also now have a bad drain on my mk 2 vrs 2012 estate using a jump pack too often ... brand new battery 100 amp bosch 

 

no new equipment fitted but did originally have tow bar removed and all its wiring tucked up under back bodywork? 

I sadly ended up selling the car. I had it looked at again by another electrician and he was as confused as I was by everything. 

 

Now own a 2018 VW Passat. 

 

thank you ... it seems i might have to go that route sadly .. love the car 

 

it started soon after having a new alternator belt and battery fitted 

 

still winder about the alternator diode but 500 squids to swop it over 

Edited 18 May, 20242 yr by promomast

I am assuming that you car has stop start and that you have a AGM type battery fitted?

 

If so, yes, you should code the battery, as by not doing so, it can cause issues with the voltage regulator (attached to the alternator).

thank you ... no stop start thankfully 

 

new 100 amp bosch battery ... garage puts drain around 0.6 amps 

Hello,

I have been suffering from parasitic current draw on my 2012 Superb 2.0 TDI. Unfortunately, intermittently, the issue sticks up its head every once in a while. First of all I want to say say that pulling fuses is not the way forward diagnosing the issue. As soon as one pulls a fuse while measuring amps, the system that has been brought to sleep will be reactivated when pushing back the fuse in its slot.

On YouTube I have watched the video published by the Humble Mechanic on this subject which sounds to me a healthy approach. To identify a current in the first place I´d suggest to watch this video

I have done this a couple of times now without success.
I also have tested non-fused devices such as alternator and starter motor.
With OBDeleven I was made aware of 2 faults generated by the driver seat control module, when I bought the car 8 years ago I already saw the seat sliding forward and back with some hickups and the memory of the seat position also shows strange behaviour, espacially when the second key (used by my wife)
Anyone here familiar with this issue and able to give me push into the right direction?

For me the issue resolved today, as a matter of fact is was a very simple one, to be honest, it never came up in my mind to think into this direction. Anyway, I removed to module, sprayed the contact pins and sockets with ACF-50 spray (Ebay), waited a bit, put the whole thing back together and now it is working again.

The stuff was recommended by a friend to protect the trailer electrics (socket and plug) from corrosion. This treatment triggered me to give it a try with the seat control module and voila, issue resolved

Edited 7 March, 20251 yr by Agent327