You didn't say what the temperature was when you got home when on the 5th attempt...the X started...even with the battery at 11.6 volts.
I don't think EWS was the main culprit as you came to believe...my money is on the low
electrolyte level in the battery in at least the 3 cells you mentioned. EWS may have been a victim of the "low voltage" situation...as it can be affected by low battery voltage as the inability to update the "rolling code" feature (that is part of
EWS 3.3).
If the ambient temperature is around 30 °F and the battery electrolyte is low...that will reduce cold cranking amps. and diminish the battery's power output. Obviously as the ambient temperature rise...even with low electrolyte...the cranking amps required to start the vehicle is less.
Your thread does bring up a VERY GOOD point...and that is to remember simple battery maintenance. Sometimes we forget that some of our batteries actually are actually NOT maintenance free...and have caps/covers that allow checking the battery fluid level.
Your thread also reminded me of a similar situation with the battery for my riding lawn mower. Before I purchased a "float charger" for its battery...it was hooked up to a regular battery charger for a approx 6 -8 weeks before mowing season. When I installed it in the mower that spring...the mower's engine would try to turn over but wouldn't start. I knew the battery was charged...but wondered if it was just old. When I went to remove it from the mower to go buy a new one, I noticed (thru the white battery case) that the fluid was low. Just as you did, I topped off the battery fluid and reinstalled it in the mower...this time it started.
Lesson learned here was like your situation...a seemingly charged battery will not have enough power to start the engine if the battery electrolyte (battery fluid) is low.
