Strange Behaviour from my Scirocco

[Packham93]

So I have a 2010 VW Scirocco 2.0 TDI

It has just had its year MOT and Service,

About 6 months ago my battery was completely dead so I had it replaced, Over the past week it has really been struggling for example I can hear my locks flickering when it's trying to start and it really sounds like a dead battery, as it sounds like there's no power in the battery. I was testing it out this morning and have realised that it doesn't start at all unless you press the gas and it still really struggles then! On the way to work this morning I went to use my driver side window so I pressed the button down once which the window then normally automatically goes all the way down until you press the button again but it didn't do this, as soon as I took my finger off the button the window stopped going down. So I then tested my passenger side window and it wouldn't go down at all.

Now I remember when I called the green flag out 6 months ago when my battery died I brought a new battery off them, The guy said to me I don't have the same size battery or voltage battery that you currently have in there it the next size down, but dont worry he said you wont noticed any difference in the power. I'm wondering whether that has anything to do with it, or if any one could help me. As I know my car wont start in a few days as its getting worse and worse.

[Packham93]

Can anybody please help?

[Deagol]

Sorry to hear of your problems.

If I were you I would check the "size" of your battery against what ought to be in the car. I am no technical expert, but would expect the starter motor on a diesel car to need a bit more power to turn the lump and compress the air in the cylinder ready for fuel injection. A petrol engine, being different compression, would get away with a lower output battery - I assume (I am no expert, remember)

A quick snapshot from Google indicates that batteries recommended for a 2010 2.0D has about 20% more cold-cranking power capacity than a battery recommended for a 2.0 petrol. This could be your general problem.

And if you are over-working a "petrol engine" battery, I would anticipate you could kill it through excessive power drain. Your Green Flag man might have done you no favours at all with his "next size down". If I were you I would get some facts from a local VW dealer, or independent battery place, then go back to Green Flag and raise a complaint.

Good luck, hope this helps.

D

[Cuprabob]

The rating of the b attery is given in AH plus a cold start current amperage. As said above the latter is very important in a diesel car due to the higher compression. The voltage of the battery will be correct.

How is the car used? Does it do many short journeys? Could be the battery is not getting enough time to recharge. Modern cars with all the tech are tough on batteries.

Green Flag should warrant the battery for 1 year, so get them back out to check it.

Give the car a good long run to charge it.

[Stu13R]

The rating of the b attery is given in AH plus a cold start current amperage. As said above the latter is very important in a diesel car due to the higher compression. The voltage of the battery will be correct.

How is the car used? Does it do many short journeys? Could be the battery is not getting enough time to recharge. Modern cars with all the tech are tough on batteries.

Green Flag should warrant the battery for 1 year, so get them back out to check it.

Give the car a good long run to charge it.

Good points raised here. With a standard acid/copper plate battery they are perminantly damaged if you go below a certain charge. My wife's car had a fault which ran her 2 week old battery totally flat causing the plates to warp and kill it.

100% get VW to provide the right battery spec and go back to Green Flag. Tell them you need someone to come out and swap it straight away or you will have to claim for a hire car. Speak to the complaints manager and don't take an excuse for why they can't transfer you to them. If they don't agree to swap it immediately threaten to take the matter to the Odbudsman to deal with. They will give you a battery just to save the grief,

[Packham93]

Thanks for your responses,

My drive to work is about 6 or 7 miles or the motorway.

Could it be my alternator? My car really struggled to start this morning to get to work, once I got into work I turned my engine off and on and it started fine..?

[Deagol]

The "short" commute might have put enough back into the battery for a restart of a warm engine, but all posts above should be followed up - especially telling Green Flag to supply correctly rated battery.

When it is time to go home, I suggest you make sure the DRL (headlights) are off - even if the best you can do is to switch the headlight swift from "Off" to "parking lights only" to shift a bit of power consumption from lights to starter motor. I think that if the alternator was defective, your battery would not recharge as the engine was running and the red warning light (battery shaped) would light up on the dashboard as you drove.

From my amateur perspective, your car appears to have the wrong battery - swap that for a correct one and your problem should disappear. Maybe whilst you wait for Green flag to get their act together, drive home the long way to keep some charge in there. Don't restart the engine at the end of a journey "just to see" because you'll be using up valuable stored charge which will be needed for the trip home.

D

[Packham93]

Thanks for you help guys

[bitmadmax]

Wasnt there also an issue with battery drain with some head units/can gateway?

[Packham93]

Sorry I dont understand what you mean....?

[Phil]

Wasnt there also an issue with battery drain with some head units/can gateway?

Not heard this but would love to know more....

Not diesel but i've recently had to replace my battery and do similar journey to and from work. By the end it had enough for one start and that was it. Sadly sounds like a simple fix was messed up by green flag.

[dimexi]

Wasnt there also an issue with battery drain with some head units/can gateway?

Yes, on cars of a certain age... IIRC circa 2007, so OP should not be affected, especially if they havent tampered with the head unit.

I personally think the lower capacity battery, and high demand on it (DRLs etc) is the issue. So green flag need to sort.

I find the OEM battery is very rubbish too! I need mine changed but I havent got round to it! I want to get a "varta" battery fitted

[Packham93]

My car now start absolutely fine without any issues, and I haven't had any issues with it over the past few days now. I stuck in two minds whether to go to the scirocco garage to get it checked or wait to see if it does play up again. Could it of been a loose connection on the battery maybe?

[dimexi]

If you have access to VCDS, get some error codes out. The low battery ones are easy to figure out... If not, I'd STILL get green flag to change the battery