The Flip the Fleet project, partly funded by the Ministry of Business, Innovation and Employment's Curious Minds initiative, aims to dispel myths about EVs by collecting data from owners from around the country.
At the beginning of each month, participants receive emails reminding them to upload mileage, charging patterns, the last trip taken and other data gleaned from their vehicle's odometer.
Wellington EV Owners Group member Sigurd Magnusson has also polled owners on how and where they charge their vehicles.
"EV owners particularly enjoy not having to interrupt their drive home or make a special trip to a petrol station," he said.
"The lack of fumes and hazardous substances makes refuelling with electricity a more pleasant experience.
"Nor do they have to dig around for a discount voucher or credit card - home-charging means you just get one automatic bill at the end of the month - which, in a way, is interest-free credit for up to a month.
"There are no snacks to tempt the kids, no waiting for a bowser, and no queues of people getting coffee - making the whole process take 15 seconds rather than 15 minutes."
Thirty-five percent of 310 electric vehicles being monitored by the project used a timer to charge between 11 pm and 7am, when the price of electricity is much lower.
"That's also better for New Zealand - we need to reduce electricity demand in the morning and evening peak periods if we are to reduce the amount of coal and gas used to make electricity," Magnusson said.
Many of the owners also had solar panels at home.
Around 40 per cent charged their cars using standard 8-amp household plugs, and slightly more had installed higher capacity plugs, such as caravan plugs, at home to charge more quickly.
Owners also reported carrying charging leads in their vehicles and topping up their batteries before making longer trips.
As at May, there were more than 3500 EVs in New Zealand, compared with fewer than 200 four years before, and pure EVs were now out-selling plug-in hybrids.
The large majority were registered in Auckland, with smaller clusters in Wellington, Canterbury and Otago.
The National-led Government has an aim to get 64,000 EVs on New Zealand roads by 2021, including one third of Government vehicles, through incentives such as allowing them to use special vehicle lanes, exempting them from road user charges and subsidising projects through the Low Emission Vehicles Contestable Fund.