Showing posts with label efficiency. Show all posts
Showing posts with label efficiency. Show all posts

Saturday, December 8, 2012

Staying Alive at 35...Percent SOC


It’s a comfortable feeling starting your day with a fully charged EV.  Even though every EV has its range limit, a full tank of electrons gets the day off on the right foot.  But lately, I have picked up the annoying little habit of forgetting to plug in.  So I decided to experiment yesterday when I only had 35% state of charge when I began the day—can I survive my day on 35%?

I had a little extra distance to travel because I had meetings in various places.  I was not going to make it without some charging along the way, and some highly efficient driving too (which is not my strong suit).

The first leg of my trip took me from Corona to Riverside, a distance of about 16 miles all on surface streets.  I usually burn up 20% to 25% of my battery making this drive when not trying to be efficient.  Instead, I hunkered down, kept the accelerations slow and steady and stopped well in advance to collect as much regeneration power as possible.  I made it using only 17% of juice—leaving me with 18% of battery in the tank.

The next leg of my trip would take me from Riverside to Ontario, a distance of about 22 miles.  18% wasn’t going to cut it, but I know all the EVSE’s in downtown Riverside so I juiced up during my meeting.  After about an hour and 20 minutes I was back up to 45% state of charge—more than I had hoped for.

I hit the road, mostly freeway travel this time, and paced a few big rigs along the way to increase efficiency—and increase the risk of a rock chip in my windshield.  Upon arrival in Ontario, I had 28% state of charge left—meaning I used 17% of my battery on this leg of the trip also.  Luckily this stretch of freeway is mostly flat and the day had warmed up.  Combined with a little drifting behind big rigs, it really boosted the efficiency.

Time for lunch and another 6% to 7% drain.  I tried charging at my usual lunch spot, but two Chevy Volts ruined that plan.  So I plugged in at Kohl’s across the street.  The problem is that I don’t really like to shop.  So what to do while the car charges?  Wait…and wait…and wait.  After what felt like an hour, but in actuality was only 15 minutes, I had to get back to the office.  My state of charge was back to 28%.

Finally, time to go home, Ontario back to Norco, about 15 miles, all freeway.  Usually I can burn up 25% making this drive when I am carefree.  But a Friday night commute in Southern California saved the day because of the excessive stop and go (charge and go) traffic.  I made it home with 16% state of charge—meaning I used 12% of the battery on the way home, a personal record.

While it’s never enjoyable to start the day with a drained battery, it is possible to survive.   If you know where EVSE’s are located, and you know how to squeeze out the efficiency when needed, you can survive at 35…percent.

Friday, June 15, 2012

The Emotional E: Fun vs. efficiency

The Active E guru (sensei, maestro, etc.) Tom M. set out a list showing how the consumption rate (which is expressed in miles per kilowatt-hour or "mls/kWh") translates into the expected range of the Active E.  The more efficiently you drive, the farther you go on a single charge.  It is based on usable battery power of 27 kWh (the E has a 32 kWh battery pack, but only 28 of those kWh's are available to use and about 1 kWh is apparently held in reserve).  The list went something like this (I say something because now I can't find the list, but this should be the same since its based on 27 kWh):

          2.2 mls/kWh = 59.4 mile range
          2.7 mls/kWh = 72.9 miles
          3.0 mls/kWh = 81 miles
          3.3 mls/kWh = 89.1 miles
          3.8 mls/kWh = 102.6 miles
          4.0 mls/kWh = 108 miles
          4.4 mls/kWh = 118 miles

Knowing your range is important, but how does the Active E make you feel?  There is an emotional connection that everyone feels almost instantly when riding in, and especially when driving, the Active E.  It's quiet, has smooth, instant acceleration, and can beat just about any car off-the-line.  It moves without a drop of gas nor a hint of exhaust.  And it handles like a BMW.

I notice myself struggling between an all out urge to hit the accelerator and have fun (efficiency be damned) or feeling the serene nirvana of achieving the best in efficiency the car has to offer.  So I thought it might be interesting to translate the mls/kWh into the emotional feeling that accompanies it:

         2.2 mls/kWh = whoo hoo, I'm having the time of my life
         2.7 mls/kWh = trying to be serious, but still having fun
         3.0 mls/kWh = moderate restraint, not happy, not sad
         3.3 mls/kWh = repeat with me "must not floor it, must not floor it, must not..."
         3.8 mls/kWh = I am turning into a robot...
         4.0 mls/kWh =  come on! You're killing me!
         4.4 mls/kWh = I am at peace with efficiency.

Choose your level of fun vs. efficiency and drive accordingly.