January 21st, overnight temp hit -28C, my Soul failed to start. It had started a couple of times at that temp before the 21st, but couldn't do it that day.
Now, mea culpa, it has M1EP 10W-30 in it, a nine-year old battery (original!), and was not plugged in.
Since then, have been plugging it in, but even with that, it struggles to start as we are still in -28C overnight temps.
Battery is obviously on its last legs, but can't change it now or change the oil, so we will see what happens.