A better thinking battery

An intelligent battery meter for electric vehicles could prevent drivers running out of charge and coming to a standstill at inappropriate times.

Waikato University electronic engineering student Philip Rowe has been working on producing an intelligent battery meter, part of an honours project that won the annual design competition sponsored by the Waikato branch of IPENZ (Institute of Professional Engineers NZ).

“We were set a challenge: to replace something that’s flawed,” says Rowe. “The voltage method of measuring battery power levels is only any good when the machine isn’t moving. We wanted to develop a meter that worked more like a petrol gauge on any lead acid battery.”

The battery meter project was started by Kyle Pennington who created a bench prototype, and a working model has since been installed and tested on a motor scooter belonging to Professor Jonathan Scott – Rowe’s supervisor.

“The idea is that the meter gets to ‘understand’ the battery so it can give an accurate indication of how much power remains,” says Rowe. “We combined three different measuring methods found they complemented each other and by switching between them we could get a meaningful read out.”

Professor Scott, himself a scooter owner, says battery meters have been a weak point in the world of electric vehicles for many years. “So much so, people are sceptical about our claim to have a practical, workable solution to the problem. It’s time for this technology to cross the divide into the commercial arena, with serious investment and rigorous testing.”

Long term, Rowe would like to think the meter could be manufactured for common use. It has potential to be used in golf carts, mobility scooters and other electric vehicles. In the meantime he’s begun studying for his PhD, working at Plant and Food Research at Ruakura full-time to develop optical sensors to determine the properties of fruit.

Rowe says he’s pleased he decided to study electronic engineering. “It offers a huge variety of different areas to work in – and there’s a great sense of achievement in developing something that is practical and useful.”