The car is here: http://www.evalbum.com/5368
It's the result of a bet that I couldn't built an EV for £750 (1000$).
It is basically an urban run around as most of my driving is in and
around Milton Keynes which has the highest density of ev charging points
in the UK and many are free! It became part of my PhD studies. The area
is full of gently rolling hills and is not flat which would help and yes
power consumption is often higher in one direction than the other.
I simulated many donor cars and came to the conclusion that the biggest
factors in efficiency were weight and friction/aerodynamic losses.
Interestingly if you look at the weight of European vehicles of the last
20 years today's vehicles have doubled in weight compared to their 20
year ancestors despite the use of lightweight materials. Some of it is
improved safety but a lot of it are the extra gizmos that are deemed
essential for today's market. Do away with those and the weight comes
tumbling down. So I selected a Reliant Kitten and found one that was
being used as a chicken coop in a barn.
The result is a vehicle that weighs only 545kg */including batteries/*
which means I'm not expending energy moving things like electric
windows, power steering etc etc. There is no wiring loom just a CAN bus
and power and all the ancillaries are controlled by multiple micros. All
the lights etc are LED including the headlamps, heating is done by
taking the hot air from the motor cooling fan and ducting it into the
vehicle. The whole vehicle is designed to be as miserly as possible.
That is why it gets the good figures. Unfortunately the car has the
aerodynamics of a brick but there may be some room for improvement.
It has also allowed me to do some clever power management to get the
most from the batteries. One big improvement is the 22x 2600F
ultracapacitor pack that is connected in parallel with the batteries.
These smooth out the power surges and allow more power to be harvested
during regen because they can accept higher charging currents than the
battery packs. End result is better battery life and the ability to
extract a bit more capacity. It is quite fun watching the fuel gauge
fill up when braking.
Anyway I can cope with manually winding the window up and down, locking
the doors individually etc for the 1.5p (2 cents) a mile it costs to
run. Especially as gas/diesel is around £6 (7.2$) a gallon in the UK!
If I had the aerodynamics of a Leaf, I'm sure I could get the figure to
around 100 wh/mile. Not totally sure it would be cost effective though!
Steve
On 07/12/2018 15:34, Peri Hartman via EV wrote:
Steve,
Is your worst case really 230 Wh / mile? That's rather incredible
(translates to 4.3 miles / kWh). That's around the *best* I ever get
with my Leaf, in summer. What are you driving, and where?
Peri
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