My method of charging to 50% 1-2 hours after I arrive home, then
charging to my desired charge level just before I leave in the morning is working very well. While I have to reset the timers each day, it only takes a minute to do so. I may set maximum charge to 80% to control the charge in case I miscalculate. I have found that a very close approximation of time needed to charge on L2 (for those who have Gid Meters and know their starting SOC) is 3% every 10 minutes (=18% per hour). This formula works very well in the range of 30-80% SOC. For instance, when I charged for 2 hours and 10 minutes:
Estimated change in SOC - 39%
Actual change in SOC - 38%
While not as elegant or easy as being able to set the desired SOC directly, it isn't much trouble to do. My plan is to keep the SOC at 50% as much of the time as possible to minimize battery capacity loss. For my routine, it works very well. During the week, I charge from 50% to 70% in the early morning, arriving at 70% half an hour before I leave for work. When I get to work, my SOC is 50%. The Leaf sits out in the sun for the next 10 hours at 50% charge. The drive home leaves me at about 30%. An hour or two later, one of the timers charges the Leaf back to 50%, where it sits for about 10 hours until early in the morning. The cycle starts again.
For anyone whose schedule/driving needs are fairly predictable, this is probably the best care one can give to the battery. Will it be any better than just charging to 80%? Hard to say, but given early warning signals from some of our friends in Arizona, the small amount of extra effort is worth it for me. Just wish I had a place to park in the shade during the summer. :evil:
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