I have 2019 L405 3ltr diesel autobiography…I’ve had it since new and other than a few minor issues its been a thoroughly reliable. However recently when I’ve been washing it Ive tried to open the boot to wipe the sills and whilst boot unlocks it doesn’t actually open i.e. the normal process of the hatch auto opening doesn’t happen and I have to heave it up manually. This however isn’t the main issue as when I return to start the car its completely dead; well not completely dead as it locks and unlocks with the remote and interior lights are working but the car won’t start and all the in car displays are completely blank.
The only way to fix it (that I’ve found) is to disconnect and reconnect the battery following which everything jumps back to life!!
Anyway just wondered if anyone else has had this issue and if there is another way to reset everything without disconnecting the battery because as anyone who has carried out this task knows’ it’s a right pain in the backside!!

And it starts absolutely fine once 'reset'? I was going to say it's probably just the original battery on its way out but that does sound strange.... Could well just end up the battery is on its way out though... FFRR SDV8 Autobiography

second battery died and draining the main one? It happened to me on my old 2004 which had a second battery fitted.

Was driving along and the whole car died, engine, lights, everything. turned out the 2nd battery was draining the main one until there was no power left.

Boot opening is the first thing to fail with a worn out battery so I'm with the others... check the voltage on both of yours...  Pete

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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Thanks everyone and good advice...I'll check the battery!!