From the very beginning, we have been looking for a solution without compromises. We were looking for batteries of the highest quality that are reliable, readily available on the market and powerful enough to bring our electric dreams to life. For us, it was a no-brainer: we found the right part if it could deliver at least the same performance of the car as it had in its previous petrol ‘life’. Do you want to know what kind of drive we ended up with in the Minis we converted? Then you’ve come to the right place; read on!
Without further ado, the basic configuration uses 4 Tesla batteries, two under the front seats, one on the rear panel of the car and one in the rear subframe.
Carborgs powered by Tesla
Tesla models need no introduction, they are at the forefront of the electric vehicle industry for a reason. We are talking about high quality batteries with very good energy density, a promising number of charge cycles, liquid cooling, extreme security (per cell, secured by properly sized wiring). Another advantage is that they are relatively easy to obtain, you can buy them from many dealers, so our partners can order them directly to their own workshops for a conversion with much simpler logistics.
We have designed a unique mounting box for the Tesla batteries that provides adequate mechanical protection and fixing. During the development, we also carried out load tests using the finite element method, so you can believe us when we say it’s guaranteed to last!
Customised for racing and winning
GOSH is our dark green high performance electric vehicle with an orange stripe, into which we have fitted a fully customised battery pack. We used pouch lithium cells as this cell offers the best modular installation options, allowing us to customise the placement and size of the battery to our exact requirements.
As GOSH is a race car, we chose the rear row of seats for the battery pack, low enough to concentrate the mass in the middle of the car. The 200 cells were attached with 80 bus bars and 800 bolts (it was a very tough day!), resulting in a 144V/100Ah battery that can even deliver 1500Ah of power for short periods of time. All of this, weighing around 80 kg, made it suitable for use in the race track.
We have created a liquid cooling circuit between the cells to keep the batteries at the right temperature at all times. As an extra, we have also installed an external rapid cooling unit that can be connected to the battery during pit stops and cools the pack down to the right temperature in a short time when the charging power is high.
For both batteries we use an active cooling and heating system developed in-house. We also had to find a solution to the fact that the summer heat, the winter cold, the warming up during charging, the strong accelerations would put a thermal strain on the batteries. After some thought, we have installed a Peltier battery cooler and a ceramic heater in the boot. Constantly monitoring the battery’s temperature (even while charging), we were pleased to find that the kit always maintains the correct temperature.
Safety and “feeding”
The batteries are protected by a Battery Management System (BMS), which is an extremely important electronic system responsible for the efficient and safe operation of lithium-ion batteries. The functions of the BMS include charging and discharging the battery cells evenly, monitoring their temperature, maintaining the balance between the individual cells and protecting against overheating, overcharging and overloading.
We have installed an on-board charger for charging via the home network so that anyone can charge the vehicle without compromise via the conventional 16A home network. We proudly present our latest development, a three-phase 10 kW charger that can significantly reduce the charging time (from about 5 hours to 1 hour). Not bad, right?