kolmstead
Well-known member
Jumped in my Leaf this morning and headed off to work, just as I've been doing for 35 months. Twenty degrees outside, but nice and warm in the Leaf. After about six miles, I turned around, drove home and got my truck. GOM was dropping like a rock, but more importantly, I couldn't get my miles per kWh above 3.0. First time my Leaf couldn't safely do the job I bought it to do.
Leaf number 257. I always preheat in the winter, and drive in ECO mode with AC off, temp set to 61 degrees. ECO limits heater power consumption to about 1500 W. Several things were working against me. Installed new Michelin Primacy tires about three weeks ago, and saw an immediate drop in efficiency. I was averaging 4.8 mpk before, now I'm lucky to get 3.9. And I preheat just long enough to make the cabin comfortable. The heater probably draws 4-5 kW at first, so the on-board charger can't keep up. I've seen a drop of two or three Gids from normal 100% readings, presumably due to preheating. So, loss of efficiency due to tires and some battery discharge due to preheating. Oh, yeah, two bar loser, roughly 25% loss of battery capacity because I live in the Mojave Desert. Turbo3's battery app was showing about 72% capacity remaining this summer; now 76%. And let's not forget battery temperature. I failed to check battery temp with Turbo3's app, but the car showed four bars. Probably 45 degrees or so, considering 20 degrees outside and charging terminated a couple of hours before I drove it. Tony Williams' range chart says to deduct 1% for every 4 degree F temp reduction below 70F. So maybe 12% today.
Commute today about 40 miles, 35 ordinarily.
After I got to work, I wondered if my gut feel was right, or I was just an old fuddy-duddy. Can't argue the old part. Being an engineer, I started running numbers. We know that the Leaf when new has about 21 kWh usable capacity. If my capacity is truly 76% of a new Leaf, then it was probably about 64% today because of the cold. I was getting about 3 miles per kWh. So my maximum range (to turtle) was about 0.64 * 21 * 3, or 40 miles. Good thing I turned around. It's important to keep a healthy reserve, especially when outside conditions are severe.
New strategy. If the temp is over 25 or so, it is probably OK to drive the Leaf. If it's colder, or I need to go further, I'll have to drive something else. Maybe my Leaf will be usable next summer and fall. After that, I'll get a new battery or it'll go to a charity. In less than four years. Sad. I thought, with a 35 mile commute, that it would be good for ten years.
-Karl
Leaf number 257. I always preheat in the winter, and drive in ECO mode with AC off, temp set to 61 degrees. ECO limits heater power consumption to about 1500 W. Several things were working against me. Installed new Michelin Primacy tires about three weeks ago, and saw an immediate drop in efficiency. I was averaging 4.8 mpk before, now I'm lucky to get 3.9. And I preheat just long enough to make the cabin comfortable. The heater probably draws 4-5 kW at first, so the on-board charger can't keep up. I've seen a drop of two or three Gids from normal 100% readings, presumably due to preheating. So, loss of efficiency due to tires and some battery discharge due to preheating. Oh, yeah, two bar loser, roughly 25% loss of battery capacity because I live in the Mojave Desert. Turbo3's battery app was showing about 72% capacity remaining this summer; now 76%. And let's not forget battery temperature. I failed to check battery temp with Turbo3's app, but the car showed four bars. Probably 45 degrees or so, considering 20 degrees outside and charging terminated a couple of hours before I drove it. Tony Williams' range chart says to deduct 1% for every 4 degree F temp reduction below 70F. So maybe 12% today.
Commute today about 40 miles, 35 ordinarily.
After I got to work, I wondered if my gut feel was right, or I was just an old fuddy-duddy. Can't argue the old part. Being an engineer, I started running numbers. We know that the Leaf when new has about 21 kWh usable capacity. If my capacity is truly 76% of a new Leaf, then it was probably about 64% today because of the cold. I was getting about 3 miles per kWh. So my maximum range (to turtle) was about 0.64 * 21 * 3, or 40 miles. Good thing I turned around. It's important to keep a healthy reserve, especially when outside conditions are severe.
New strategy. If the temp is over 25 or so, it is probably OK to drive the Leaf. If it's colder, or I need to go further, I'll have to drive something else. Maybe my Leaf will be usable next summer and fall. After that, I'll get a new battery or it'll go to a charity. In less than four years. Sad. I thought, with a 35 mile commute, that it would be good for ten years.
-Karl