Sunday, August 19, 2012

A Stop Too Far

I have the new route created with sufficient gaps between stops, however , the extra stop and additional 90 miles to avoid King City is hurting my estimates. I have planned the journey with some optimism and some pessimism. Optimism is with the charging rate at most of the charging stops along the way. Pessimism in my consumption rates. The ActiveE has a built in 6.6 kW charger. Nearly twice as fast as a Nissan Leaf or Chevrolet Volt, but half that of a Tesla. I know I wont have issues at the Santa Nella or Coalinga charging stops as they will be delivering electricity at 50 to 70 amps, the Atascadero, Solvang and Thousand Oaks charger may not be charging as fast and require careful supervision to avoid ground faults and lower charging rates. Also, the ActiveE will charge at the full rate up to a 90% state of charge for the batteries, but will slow down for the last 10% so as to not overcharge the battery. I can get away with leaving early from Santa Nella, but probably not at the other stops. Currently my estimates also expect that I drive on average at 65MPH and maintain my current average eDrive rate of 3.2 miles per every kWh used. That is probably a pessimistic estimate. Based on these variables, here is how the trip pans out.

Based on the 5 stops and 437.5 miles to drive. I will spend 6.7 hours driving and 19 hours charging for a total of 25.7 hours. This won't help me with my goal of attempting to make it in a day. So what is better, trying to speed up my driving or be more conservative in my consumption to make it to LA? Speeding up 5 MPH does not help much. Increasing my average speed from 65 MPH to 70 MPH only saves a half hour, and it will probably have a negative impact my consumption rate. However reducing my consumption rate so that I get 3.6 miles per KWh or better handily improves my recharge times saving over 2 hours.

So how can I accomplish this? Multiple changes in the behavior of my driving will play a lot into this. There was a great blog posting on the Tesla website by Elon Musk on how driving behavior affects range in an electric car. By having the tires properly inflated, using cruise control for constant speed, restricting climate control, closing windows, level road driving can help significantly. Also drafting and keeping the eDrive meter in the first band has helped many ActiveE drivers achieve 3.5 to 4.0 Mile/kWh consumption rates.Also, preconditioning the batteries (pre-heating or cooling the batteries to an optimal temperature before starting my drive) may help as well.

The route I will be taking is somewhat hilly, but I can control the other elements for the most part. I will have to practice these techniques for the trip or look for another alternate route. So there could be the Plan C contingency, but it will truly test these techniques. More on that next time.

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