How old is the battery? My battery at end of life would start the car fine even when 0°F but If I left the hazard on for 8 minutes I needed a jump start.

If you try that test: run your hazards for maybe ten minutes after driving long enough to have a good charge; if the car won't start it's probably the battery.

The day before I replaced my battery it tested fine with 550 CCA. Held over 12.4v overnight so all normal tests it passed.

First time I needed a jump was from running an ac inverter, second time was from charging an iPhone less than 30 minutes, third time was 8 minutes of hazards.

With new battery I've run hazards for more than an hour (should be able to run for 10-12 hours).

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)