Date:24 April 2014
South Africa’s Antony English has converted his Jeep Grand Cherokee to electric power and slashed his running costs to an amazing 12 cents per kilometre…
The commute can be a killer – for your wallet, that is. Frustratingly, for most of us there is no practical alternative. So Antony English decided to take matters into his own hands: he converted his Jeep Grand Cherokee to electric drive and slashed his running costs to an amazing 12 cents per kilometre. This kind of thing seems to come naturally for Gauteng electro-mechanical engineer English. With a background in mining industry project management, this self-described tinkerer was well suited to tackle a project most of us only dream about.
The results speak for themselves. His creation (dubbed Freedom1) has clocked up an impressive 35 000 km of fuel-free driving in two years. On the daily 120 km round trip from his home near Kromdraai to his Centurion office, he has run out of juice only once. And he blames that on his own over-confidence. “I was driving to Bronkhorstspruit to collect biltong and was going too fast for the range I wanted,” he confesses. For the mortified English, the result was a tow home and a valuable lesson in what driving an electric vehicle entails.
Overcoming range anxiety
Even though English designed and built his system using familiar off-the-shelf industrial components, taking Freedom1 for its first real spin was a nerve-wracking experience. Laughing, he recalls: “The first time my partner Lizette and I used it in earnest, we drove to Sandton for supper with friends. But, because we had no idea what range Freedom1 could achieve, it was virtually impossible for us to relax – we were too busy stressing about making it home again!”
Happily their range anxiety didn’t last long. After much experimentation, English established that, when travelling between 90 and 100 km/h, Freedom1 is capable of covering 170 km. That drops to around 140 km when driving closer to the national limit.
With two years of daily EV driving behind him, English has developed an interesting take on what range the average driver requires. It all comes down to being realistic about your needs and making the vehicle part of your routine, he says. “As much as most of us don’t want to admit it, we’re all creatures of habit. Ninety-five per cent of people travel no more than about 100 km on their daily commute. The remaining five per cent, such as reps or those who live far out of town, are the exception. The only times we feel limited is when we want to go to Pretoria, for example, and do a lot of driving around once there, but this doesn’t happen often.”
To play it safe, English always travels with a 20-metre charging lead in his boot. Once plugged into a standard 16 A wall socket, Freedom1’s two lithium iron phosphate (LiFePO4) battery banks can receive a full charge in a few hours. “I always give my batteries a boost at work just in case I need to do some unscheduled driving around. We also haul out the lead when visiting buddies who live on the periphery of our maximum range – which typically means we get subjected to a whole lot of leg-pulling from our friends about them charging us for their electricity.”
Out with the old
An idealist at heart, English first began thinking about weaning himself off fossil fuels back in 2003. But it was only when he was busy with a case study for his MBA in 2005 that he began to take it seriously. “Although I knew it was a concept that was ahead of its time, I realised electric vehicles would eventually become the future and I wanted to design my own,” he says.
Physical work on Freedom1 began in 2009. First to go was the engine, then the automatic transmission. “The gearbox is totally unnecessary. It wastes energy, adds unwanted weight and takes up too much valuable space.” One thing that did remain was the transfer case: English wanted his vehicle to retain its 4×4 functionality.
That he understands electricity in industrial settings shows in his decision to opt for freely available, tested components that were not only robust, but simple. “I wanted to either use or modify existing technology to create something different. I definitely didn’t ‘reinvent the wheel’. My colleagues find it quite novel that I’m using components normally found in a mine setting.”
As he already had a working relationship with Brazilian industrial motor manufacturer WEG, he approached them for a motor and they obliged. In fact, they went much further. “The guys at WEG were really open to the idea, so we made a deal: they would develop the motor for me and I would give them feedback to help improve the design further.”
Shopping around Sourcing the other must-have components wasn’t so easy. “I’ve learnt so much through this process,” he says. “First off, it’s really difficult to tell up front what components are suitable or not. Working that out involves lots of trial and error. Often the claimed design capability ends up not being what you functionally hoped for.”
Then there are the issues of reliability and technical support. “What really surprised me, though was that some manufacturers simply aren’t prepared to acknowledge that their products could be improved upon or, for that matter, even break. Working through all this clutter to get what I needed took much longer than I would ever have envisaged.”
The inverter – used to convert the nominal 600 V DC current (from the vehicle’s two battery packs) to 3-phase 380V AC for the 80 kW motor – required serious modification. It started out as a normal industrial inverter, which he had to reconfigure to suit his specific needs. “Normal inverters use an AC source to deliver AC output, whereas I have a DC source and want to invert to an AC output. I also had to make sure it could provide current and voltage that equated to the torque requested by the accelerator pedal.”
The battery management system proved to be a real headache. “My first unit had inherent faults that the manufacturer just wouldn’t acknowledge, so it had to go.” It took four days to install the replacement, a design that required different connectors – all the wires to the 180 lithium iron phosphate cells that make up Freedom1’s two battery banks had to be removed and replaced. “As it was bigger, I also had to find a new position to locate it. Plus, I had to learn the new operating software.”
English sourced his batteries from the same place everyone else does: China. He chose 60 Ah lithium iron phosphate cells for their inherently stable chemistry, which is not prone to “thermal runaway” like lithium polymer. He built the battery banks (wired in series) himself – locating 70 cells under the bonnet, and the remaining 110 under the floor of the boot where the spare wheel once was housed.
Get your charge on
After experimenting with various chargers, he opted for two on-board 2,5 kW units, as he’d found this charging capacity was optimal for a normal household connection. “When using a 16 A wall socket, the vehicle takes about 8 hours to charge. That’s the limitation of the plug; you can’t do it any faster than that. With a 32 A plug it’ll take 4-6 hours depending on the board chargers selected.”
Other features he implemented include an HMI (human machine interface) – allowing monitoring of various drive chain parameters, regenerative braking, an electrically driven hydraulic pump for the power steering and a vacuum pump for the brakes.
Besides the pleasure of having created Freedom1, English has had a blast simply turning people’s heads while driving it. Last year, That 4×4 Show on DStv featured Freedom1 conquering Sani Pass. It won the Top Speed and Endurance categories in its class at Kalahari Eco-Speed Week and, last December, it took Chobe Game Lodge in Botswana by storm.
Says English: “I am very proud of what we’ve accomplished. This is proven tech, which gives us a solid foundation to work from. For me, reliability is very important. One can’t put something like this out there only to have it let people down.”
Now that the prototype testing phase for Freedom1 is formally over, English and marketing guru co-owner Lizette Kriel have launched their company, Freedom Won, and are open for business. They have already converted a Toyota Prius into a plug-in hybrid, extending its electric-only range significantly. They are also about to start converting three game-viewing Land Rovers and a river boat to electric for Chobe Game Lodge in Botswana. Freedom Won aims initially to complete four conversions per month. For more information, visit www.freedomwon.co.za
Donor vehicle: Jeep Grand Cherokee
Motor: WEG 3-phase 380 V AC permanent magnet
Output: 80 kW/600 N.m
Battery: 180 x 60 Ah cells, 35 kWh
Voltage: 600 V DC nominal
Range: 100 km/h: 170 km; 120 km/h: 140 km
Charge time: 4 hours (3 phase plug); 8 hours (household plug)
Price: About R250 000
Lithium iron phosphate LiFePO4 batteries are used in power tools and electric vehicles because they are less susceptible to fire than lithium polymer batteries. However, they have a lower energy density.