Saturday, January 12, 2013

It's Cold in California

Cold is a relative term of course.  Yesterday the high temperature was 56 degrees, which in California we call “freezing.”  It may not be anywhere near the actual freezing point, but when we have to stop wearing shorts and put on a longer pair of shorts—that’s cold. 
Cold and battery life don’t mix well, neither do extreme heat and battery life, but cold seems to zap a battery faster than heat for some reason.  The ideal battery temperature is in the low 70’s.  Recently, the outside morning temperature has been in the low 40’s—meaning the battery has to be heated in order to operate at its maximum capacity. 
The Active E has an active battery management system that both heats and cools the battery when needed.  The only problem is that the battery management system is powered by the battery.  So the more it’s used, the less power for driving.  That means fewer miles on each charge.  Preconditioning the battery before leaving home can help tremendously in these situations.  The E has the ability to use the power from my home charging unit to warm the battery before I unplug.  This gets me started on a warm note, without having to deplete battery power to do so. 
The other power drain in cold weather is the heater, and the wipers when it rains.  Unfortunately, when I use Eco Pro mode in the E, the heated seats are disabled—presumably to save power.  But the cabin heater is a big power drain on efficiency.  It seems as though the heated seats would be a better alternative than the cabin heater to keep me toasty warm, but that’s not going to happen in Eco Pro mode.  Instead, the heater stays on and the efficiency falls short of the mark. 
So far I have seen my efficiency drop from around 3.1 to 3.2 miles per kilowatt hour, to 2.5 or 2.6 miles per kilowatt hour.  That translates into 13.5 miles I can’t drive when in cold weather.  Truth be told, I’m not all that efficient to begin with.  But when my meager efficiency dips, it is a noticeable difference—but not unmanageable.  I still drive roughly the same routes at somewhat slower speeds, and have not been stranded yet.  That’s because I have learned how to manage my driving.  I am either driving well within range, or I know where to charge mid-trip when needed.
It could be worse, I hear some Electronauts are living with snow back on the East Coast—I bet they wear really long shorts.

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