Skoda Superb MKII Battery drain

[AverageMax]

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

 

 

[Paws4Thot]

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?

[rbhelle]

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.

[AverageMax]

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

[gav_is_con]

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

[AverageMax]

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

[AverageMax]

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

[Paws4Thot]

20 minutes ago, AverageMax said:

Yes it does

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

[rbhelle]

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.

[AverageMax]

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?

[rbhelle]

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.

[AverageMax]

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. 

[rbhelle]

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). 

[AverageMax]

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

[rbhelle]

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 :-)