Saturday, March 21, 2009

40 mile drive

I had some time to spare this weekend waiting for parts to come in and nothing major to get done so thought I'd take it for another drive. I first went down to Prime Shine Express and drove it through the car wash. Poor thing hasn't had a bath in at least 8 months. Next I headed off in the direction to work and drove until I had travelled a total of 20 miles. I pulled over and jotted down my exact miles and energy consumption. Since there is a lot of up hill on the way to work I wanted to break up the two directions for comparison. I headed back home and took a bit of a scenic route, including a stop at the store for milk, to get as close to 40 miles as possible just for a nice round number.

On this trip I tried to keep my average speed closer to 55mph instead of 65mph just to see if I could notice the energy usage difference. I noticed my amp gauge staying around 125 amps instead of the 150 or so I saw at 65mph. After I arrived back at home I plugged it in and did the math. I averaged 345.18 wh/mile for the 20 mile trip up the hill and coming home I averaged 242.57 wh/mile. My overall overall average for the 40 mile trip was 293.23 wh/mile. This is considerably better than the 350 wh/mile average from my "Inside Drive" video doing 65-70mph most of the way. I'll continue to test things to improve this number over time like moving away from the Z rated tires, perhaps a belly pan or anything to improve rolling resistance and aerodynamics.

I used roughly 50% of my pack during the trip in the hills at 55 mph. At least I know even after my pack has aged and lost some capacity I'll still easily make it the 35 mile trip to work where I can recharge.

Speaking of recharging at work I just got word that everything is go on the plug getting installed and the job is suppose to start next week with a two to three week time frame. Most of the time is waiting on some parts, I think the pedestal with all the plugs. I'll get some pictures as the work progresses on that too. Once the plug is in I'll be ready to start commuting with the car. There are of course things left to do but they will be done here and there when I fell like it now, no more rushing!


Anonymous said...

how do the amenities like lights and heating and electric windows influence the endurance?
I suppose there is a big difference between a winter and summer commute?
Would it make sense to replace bulbs with LEDs?

Brian said...

If I turn the lights on my BMS indicates only 1 amp of draw and I'm guessing most of that is the headlights themselves and not the other lights (brake lights, etc). I'll probably still replace what I can with LED just to squeeze out the range later.

The heater if ran on full will take about 10% of my power compared to what my average amp draw is for cruising speed. I'll be making this variable so I'll need to use the energy I need and we'll see how that works out later.

I'm thinking summer may be the worse. You can always put on more clothes and not use the heater but I can't stand not having AC when it's 100F plus around here in the summer.

JpM said...

Congratulations on a job well done! Thanks for sharing the build experience.

Are you an engineer? If so, what field? Thanks.

Brian said...

Does software engineer count? :)

Anonymous said...

How does your S2000 compare to the Tesla Roadster in terms of weight?

Brian said...

Sadly it doesn't compare at all. The Telsa weighs in at 2723 lbs. My S2000 3200 lbs. 480 lbs heavier isn't too bad until you consider the fact that their battery is slightly more than twice as much capacity. I believe they have 1000-1100 lbs of battery where I have about 550 lbs. So I have a lot more "dead" weight. They are also using a state-of-the-art AC indcution motor which AC Propulsion won't sell to me even if I had the $30k to buy it. I have more of a sweet looking Honda Civic when it comes to performance :) I didn't set out for a screaming stop light racer though, I just wanted something electric and made it as fast as I could afford. ;)