|Location||Leicester, England United Kingdom map|
|Vehicle||1998 Lotus Elise S1 |
Probably the best and lightest sports
car on the road.
Only 118bhp from the ICE produces 0-60
in 5 seconds.
|Motor||Siemens Ford Ranger/Siemens 5133WS20 3-Phase AC|
For cost reasons I am using one of the
Ebay sourced ex Ford Ranger motors
which I have modified for non oil
I have sourced another three motors for
future projects and would be interested
in the gearbox for a Ford Ranger EV if
anyone has one available.
|Drivetrain||Siemens 5133WS20 motor directly connected |
to the existing gearbox/differential fixed
in third gear.
|Controller||Siemens Simovert 6SV|
I was lucky to purchase a used Simovert
from the ever helpful Evisol who helped
me greatly during this project.
Due to a lack of cost effective EV
inverters, I am working on modifying an
industry standard inverter for my next
|Batteries||94 Hi-Power LiFePo4, 3.20 Volt, Lithium-Ion|
The cells are 50Ah in a rugged plastic
Unlike Thunder Sky cells, these do not
require clamping together to stop them
expanding, which helped when installing
They only have 6mm threads in the
contact studs which are rather puny.
They came with a bag of aluminium
screws which were ditched for stainless
steel hex bolts for a better and
The link bars appear to be very thin
but carry the current (140A max.)
without noticeably warming.
|System Voltage||320 Volts|
I now use an Elcon charger as my Brusa
charger failed one day unexpectedly.
It is a much cheaper charger from China
which communicates with my BMS via CAN
It works as well as the Brusa but I had
to modify the BMS control terminal
software to automatically start the
charger charging as it had originally
to be initiated via the BMS touch
Because I charge on cheap rate
electricity at night by using a time
switch, the charging did not start
automatically but needed to be
initiated by pressing "Start" on the
The Brusa is an excellent software
configurable charger and very compact
although extremely expensive compared
to the Elcon.
To be fair, the Brusa charger was
repaired under warranty even though the
warranty period had elapsed.
|Heater||Ceramic electric element from a 1800 |
watt room heater I purchased from Ebay.
This is only 100mm x 100mm x 15mm wide
and has a 120mm computer type fan mated
to it. It seems quite happy with the
300v pack supply and doesn't overheat.
I am pleased I changed my original idea
of using the coolant heat to pre-heat
the heater air as it simplifies
pipework in the rear of the car and
tests have found that there is very
little heat generated unless heavily
I used the original heater matrix as a
radiator and sat it behind the RH side
The cooling fan only starts running
after much abuse has been handed out in
|DC/DC Converter||Siemens , part of the Simovert inverter|
60A at 13.1v
|Instrumentation||Lotus "Stack". The inverter has a |
compatible tacho pulse output which
works perfectly with the Lotus "Stack"
instrumentation which is scaled up to
8,000 rpm. The speedo has a pickup on
the rear wheel hub so that still works.
|Top Speed||90 MPH (144 KPH)|
I am using third gear only which seems
to be dead on.
1st gear has uncontrollable wheelspin.
My top speed is only limited by the
150A limit I have given the inverter to
keep the batteries to 3C for longevity.
This limits the motor to 30Kw although
it is capable of short term 67Kw with
90 mph is at 6,000rpm so there is
plenty left as the motor tops out at
|Acceleration||I haven't timed it yet but when the |
battery current is limited to 100A (2C)
and in third gear, I get about 10 - 12
When I increased the current limit to
140A it is much quicker and now serious
fun and I can keep up with hot hatches
on country roads.
Well worth the possible reduced cell
Remember, this is using third gear
only. I haven't tried 1st or 2nd gear
for performance tests due to the
stresses on the transmission.
Because the acceleration is so linear,
the speed is deceptive and you pull
away silently from virtually all
traffic after a couple of seconds.
Only a noisy clutch slipping start from
an ICE can beat me.
|Range||60 Miles (96 Kilometers)|
My furthest trips have been a couple of
55 mile runs to the South of Stratford
Upon Avon and also to Newark, about the
same distance North.
The cell voltage was beginning to dip
at the end, but I feel it had a fair
|Watt Hours/Mile||200 Wh/Mile |
I haven't used the calculator yet but I
use a second hand house electric meter
from Ebay to note the power used to re-
charge and I am amazed with the
On a drive to work of 13 miles I need
about 2 - 3 KWh (two - three units) to
re-charge the batteries.
Some of this is at silly speeds through
Why have we waited so long for electric
|Seating Capacity||Just two slim lithe people |
(surprisingly like myself!)
|Curb Weight||1,800 Pounds (818 Kilograms)|
The Lotus is approx. 800Kg in standard
I would expect it to be about 950Kg in
The only changes I have made is to fit
stronger springs at the rear to offset
the battery weight.
|Tires||Toyo Proxes T1-R running at 35psi|
|Conversion Time||Started in October 2007, it is now |
February 2012 and it is all finished
and working with the addition of a
Guantuo BMS sourced from China.
|Additional Features||I used the original gearbox for now but not the |
clutch as clutches are for ICE's.
I am staggered how many people discuss using auto
transmissions with electric motors on forums as they are
so inefficient and simply not required.
The Lotus for various reasons lends itself well to EV
I fitted a spring recoil cable drum with 15 metres of
cable for charging, in the exhaust silencer space.
This allows plenty of cable to reach friendly pub
For speed, I have also fitted a 16A marine grade plug
socket where the filler cap is as it is easier to access
for home charging.
It is surprising how many areas there are for batteries,
in the fuel tank low in the centre, in the front where
the Pb battery and heater matrix was, and in the rear.
Being able to use the original instrumentation gives it a