Submitted by mpottinger on May 1, 2013
I've been experimenting with different charging strategies. This past week when I set the car up for overnight charge, I've been calculating the charge needed then lowering the amperage from the 40 max to whatever number is necessary to have the car complete charging right before I leave the next morning. (Please note that at least this time of year, I live in a cold location.) Advantages I've noticed: I leave with a full standard charge with no vamp loss. The battery and the cabin are warm, even with no preheating, presumably from heating of the battery for charging. No limit on regen when I leave. No massive energy use spike as the battery warms when I leave.
My question is, what are the downsides to low amp charging? Overall more energy use? Detriment to the battery in some way? The energy use question is a complex one. You have longer battery heating, but you don't have that big spike in the morning. You also are regenning from the start, which I normally would not be able to do in cold weather. Also, is there generally a preference or benefit for faster charging at 40 amps versus slower charging at lower amps? Finally, do the answers to these questions change with changes in ambient temperature?