ELECTRIC AVENUE

DR TIM TALKS US THROUGH THE INTRICACIES OF REPOWERING VEHICLES WITH ELECTRIC MOTORS

- TIM BARTROP

THE popularity of electric vehicles (EVs) continues to increase, with a variety of manufacturers presenting electric cars to a market still learning how to choose one. You can also build an EV and, sure enough, I’ve now been asked by a client to engineer my first one: an ICV (Individually Constructed Vehicle) trike. So I had to deal with three engineering aspects at the same time: an ICV, a trike and an EV all in the one project.

The only part that I was not experienced in was the EV aspect, so I had to learn the current regulations. Luckily I had a good client who knew his stuff, and the result of our cooperative efforts is an EV trike called T-Rev, registered and on the road. For my part, I read everything available to be able to assist him and ensure that the vehicle met the National Guidelines for the Installation of Electric Drives in Motor Vehicles. This is available for anyone to download for those interested in going a similar route.

So this month I wanted to give you an overview of what you need to consider when constructing an electric vehicle. After all, it won’t be long before we start seeing EV street machines!

CURRENT MATTERS

NEEDLESS to say, building an EV is completely different to building a car with a regular internal combustion engine, but there plenty of rules to guide EV builders down the right path.

Most EVs will be hazardous voltage (HAZV) rated, which means they will operate above 60V DC; this is necessary to get higher power levels. Conversely, extra-low voltage (ELV) vehicles operate below 60V DC. Most will use batteries with non-spillable liquids and without discharge gas (e.g. lithium or NiMH) so that full sealing of the battery compartment can be avoided.