It's natural to assume that your cleaning has triggered this and look for related areas of disturbance, but maybe not?
The symptoms while running sound very weird, beyond my pay grade to say what might cause that, but I'd go back to basics with a multimeter:
Check battery (you imply that seems OK) and the connections to it. Then move on the circuits that are live all the time and test voltages.
Brake lights spring to mind there - I'm pretty sure they're always live. Not sure about cigar lighters? Remote locking is one obviously, does that work?
Then measure other circuits, starting at the fuse boxes or under the front passengers feet.
Hopefully someone with a deeper understanding will be along soon to point you more precisely. Just not starting can have many causes.
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation".  (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one! 
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course.  (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
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