Hey Stef,I just recently had to deal with this.
10 second delay after repeated tries failed to work.
Battery was down to only 1.1 Volts!
Dead as a door nail.
Here is what worked for me.
Kept the electronic charger plugged into the wall and the port in the trunk, hooked a fully charged battery to the jumper posts in the front.
System came to life immediately and woke the in car battery which flashed the charger to detect the battery.
Took 13 hours to revive the battery fully. The charger got very warm to the touch from 2 to 4 during charging program which was about 10 hours.
This had me more then a little concerned so I placed a fan to circulate air on the charger.
Seems to be okay now but I wonder how much wear and tear this causes to the battery and shorten its life when becoming severely discharged like this.
Thanks for the info on reviving a battery. I have a 21, and was told that, the batteries had been changed/updated. This battery would go into a sleep mode at approx 11v's and there was a button on the charger to wake the battery and car to try and start it to get it to the dealer/ or charge. I have to two charger locations, and was told the one closest to the battery (front hood) was the shorter run and better location to charge from. Not sure when this change happened or if there was a recall to update the system.
Amazing you could revive a battery from 1.1v . Fan on the charger was a good call especially in the southwest during this summer! The CTEK charger is a very good system. Use one on my 05, and it's saved a "dead" battery more than once.
Bruce