Batteries

Thanks to my good mate Leon at Lithium Power we were able to source 6 x Tesla 24v modules. At this stage the plan is to only use 5 modules, leaving 1 as a spare. Leon also chucked in a few adapter boards he designed for easy integration to the BMS. I’m pretty sure I’ll be going with the ZEVA BMS, however that is yet to be purchased.

Flywheel and Clutch

I often get asked why I am using a clutch and flywheel combo. The answer for me is pretty simple. Its for safety. Attaching the electric motor direct to the flywheel will allow me to mechanically disconnect the drive in the event of fault or failure. As soon as I push the clutch in, the drive is disconnected. The alternate to this would be to attach the electric motor direct to the input shaft on the gearbox via a coupler. I am not a fan of this method. We obviously will lose some efficiencies by using the flywheel, however after weighing it all up, I decided upon continuing with the flywheel and clutch setup.

Flywheel Coupler

The coupler is a pretty important part of the build and mates the output shaft of the electric motor to the flywheel. I originally purchased an interference fit blank from CAN EV (Canada). This coupler needs to be machined to suit and as it sits now I have a few 3D printed models to test my drawings.

Adapter Plate Update

I was delaying the production of the adapter plate as I ended up ordering a new lightened flywheel and clutch combo. I wanted to make sure that all the dimension were all good. I only have 1 chance at this adapter plate and want to get it right. Fingers crossed now that football season is finished we can make some real progress in this space.

Hyper9 Specs

Just in case anyone was wandering about the specs of the Hyper 9 electric motor. Check out the pic. If I had the $$ to bolt two of these together I would!

Now what?

Bench test! Adapter plate! Batteries Boxes! Cabling, Wiring, Mounts….the list goes on.

Donor Vehicle

So many choices! But the vehicle had to meet a few criteria. The first being the ‘weight’ of the vehicle. No point choosing a super-heavy vehicle and trying to push that around using an electric motor. The donor needed to be lightweight.

The second criteria were the driveline and gearbox type. I opted for a rear-wheel drive, manual vehicle. By far the easiest conversion is the adaption of an electric motor directly onto the manual gearbox. This may not be the most efficient, however by using the gearbox, flywheel, and clutch we have a manual disconnect from the electric motor, and for me having this safety disconnect is a big selling point in using this method. Push in the clutch and the electric drive is disengaged. Some enthusiasts will say that a direct connection to the input shaft of the gearbox is just as good and will argue that it’s more efficient, however being a DIY build, I feel safety trumps the efficiencies that I may lose.

So, what vehicle could we have chosen? A popular choice is the VW Beetle, you can buy kits to bolt up to these straight away. probable convert in a day if you had the right tools. However, I wanted something different. I have always loved the Gemini scene here in Australia, some of the turbo race Geminis go pretty hard. I ended up settling on this little ‘Grandma Spec’ TD Wagon. I chose the wagon as I felt it fit the criteria, heaps of rear space for some batteries and the total weight of the car is around the 900kg mark. Nice and light! It’s also a rear-wheel drive with a manual transmission.

Tear Down

To keep this short and sweet, the teardown was actually the easiest part. Say goodbye to a few of the major offending components. The combustion engine, fuel tank, exhaust, and associated components. For now, I’m keeping the brake system and as many of the stock ancillaries as possible. The idea will be to continue running a 12v battery to run a lot of the original electrics. This will help come during approval/engineering time. Check out the gallery below for a few before and after shots.

Electric Motor Choice

I’m no expert on electric motors, but I’ll try and sum up what I have learned and why I ended up choosing the Netgain Hyper 9 motor for my build. First of all, we should chat about the types of electric motors. For Electric Vehicles, you typically will find the following types:

• DC Series Motor
• DC Brushless Motor
• Permanent Magnet Synchronous Motor (PMSM)
• Three Phase AC Induction Motor
• Switched Reluctance Motors (SRM)

Each type of motor has pros and cons depending on how it is used. There are WAY too many factors to discuss in this blog post why one is better than the other. However, we can chat about which vehicles currently have what. The Tesla Model S is probably the best example and runs an  AC Induction Motor. We can assume that you get some high performance out if this type of motor. We can also assume that it comes at a cost! You will find DC Brushless motors in electric bikes and skateboards. A bit cheaper, but possibly not as efficient when pushing heavier loads? I’m sure discussions on Motor types will continue as technology advances. What would you have chosen?

The motor we ended going for was the Netgain Hyper 9. Netgain has penned it as a 3 Phase AC, Synchronous Reluctance Internal Permanent Magnet Motor. The sales pitch is here:

The HyPer 9 Integrated System (IS) is the ideal power-train for any light to mid-weight daily driver. Combine multiple systems for heavy-weight and racing vehicles. Its Synchronous Reluctance Internal Permanent Magnet (SRIPM) platform delivers outstanding torque and efficiency, generating higher power per pound than any other motor in its class. The HyPer 9 IS includes the 100V brushless HyPer 9 Motor, HyPer-Drive X1 Controller/Inverter, SmartView Programming Software, Low Voltage Wire Harness Kit, and Main Contactor. This system has many unique features that set it apart from any other EV solution on the market.

More details and drawings also found here.

Adapter Plate

The next item on the agenda is the adapter plate. These plates are pretty common amongst the DIY EV crew. The concept is to use a plate that precisely aligns the new electric motor to the input shaft of the gearbox. If using a flywheel and clutch, then it will align the electric motor both horizontally and vertically to mimic the exact position of the original combustion engine. A coupler is then used to attach the output shaft of the electric motor to the flywheel or input shaft of the transmission. Depending on what method you use. In my case, it’s the coupler onto the flywheel.

As you can see from my measuring attempts, I still have a LOT of work to do on my adapter plate. Check out my progress though. Any advice is much appreciated.

What’s next…

Well, that concludes the first part of this build. It’s going to be a slow process but I promise I’ll keep the blog up to date as I progress. Feel free to comment below. Anything constructive I’ll take on board.

• More Adapter Plate work
• Battery (Save, Source, Setup, and Test)
• Wiring Looms
• Charging Systems (Main Battery, 12v System)
• A whole LOT of stuff I don’t know I need to do…