2009 1.4TSI 118kW Scirocco windows rocking while starting

[underseer]

Hello!
Ever since I've bought my Scirocco in February it has been doing this weird thing of lowering the windows down, twitching them and lifting them up while starting. I can't figure out what the problem is. Has anyone encountered something simular?
Also, the interior lights and headlights slightly flicker when pressing the gas pedal or releasing it. Are these issues correlated and how can I fix them?
I'm new to this forum and I can't find a way to attach a video, should I just it on YouTube and drop the link here? It's a video of the windows twitching on a cold start.
Thanks!

[bigkris06]

Sounds electrical to me, battery, alternator maybe a bad earth? Have you had any issues with starting?

[underseer]

Sounds electrical to me, battery, alternator maybe a bad earth? Have you had any issues with starting?

It is defiently something with the electrical system, but I've tried changing the alternator and connecting 2 batteries in parralel, doesn't seem to help. Also checked alot of major earth connections, they all seem fine. Went through every control unit with my OBD11, they all seem to have rather simular voltage graphs with around an amplitude of 0.8V at peaks.
Haven't really had any problems with starting so far, but I'm not dailying it since I don't have my license yet. Every time it fired up after a couple of turns having sat for like a week tho.

[bigkris06]

I would be inclined to get someone to use it for a few days just to eliminate the battery getting a little low. I think you may find when it’s used regularly and the battery is kept fully charged it may be okay. Alternatively if possible keep the battery topped up using a trickle charger.

[Cuprabob]

The windows down / up when starting the car can be down to a faulty ignition switch. It thinks you've pulled the key out and drops the windows accordingly.

The other issue with regards to the brightness of the lights varying with the engine speed kind of points to a voltage regulator issue, which I assume was replaced as part of the alternator swap.

[underseer]

I would be inclined to get someone to use it for a few days just to eliminate the battery getting a little low. I think you may find when it’s used regularly and the battery is kept fully charged it may be okay. Alternatively if possible keep the battery topped up using a trickle charger.

Yeah, the battery that I bought the Scirocco with is only a 45Ah one with I believe around 360A of rated output. It's also pretty old, so I hope that when I replace the battery before the next winter this problem will go away. I'll try to see tho if I can get someone to drive it regularly.

[underseer]

The windows down / up when starting the car can be down to a faulty ignition switch. It thinks you've pulled the key out and drops the windows accordingly.

The other issue with regards to the brightness of the lights varying with the engine speed kind of points to a voltage regulator issue, which I assume was replaced as part of the alternator swap.

Yes, I did in fact change out the brushes/regulator unit for a brand new Bosch one, forgot to mention.
And hopefully the window issue is going to be resolved by daily use/ a new battery, just like the other person mentioned.