The label in the store says "max distance 20km" and that was good enough for Simon Johnston to part with $750 for a Segway Ninebot F25 Kick Scooter.
The official app he paired with the scooter told him the same: fully charged, 20km range.
Try as he might, circling Hagley Park in Christchurch, Johnston could not get near 20km before the battery ran flat.
"This is the fourth test on eco mode (at 15km/h). Twelve kilometres I most I've got out if it."
He is fit and well now, but four months ago, Johnston was not up to walking home pushing an e-scooter.
He'd bought this one to give him some mobility and fresh air while recovering from double hip replacement surgery, but the product claim has created another condition: range anxiety.
"When you see the battery light flashing, that's when the anxiety sets in," Johnston said.
What was the deal? How had the range claim been established?
PB Tech said the details are available prior to purchase, but only online.
In the store, customers can only see them by scanning a QR code next to the item which links to its website.
There, the retailer unpacks this 20km range as something Segway measured in laboratory conditions, with a full charge, a 75kg rider, at 60% of top speed (so, 15km/h) on a flat, hardened road, with an ambient temperature of 25°C.
"It's worth mentioning that Christchurch's temperature has mostly been colder than 25 degrees since the time of purchase," PB Tech customer service manager Fernando Vizcarra said in a statement to Fair Go.
Simon Johnston feels those are unrealistic parameters. An e-scooter has to stop and start to navigate pedestrians, traffic and other typical hazards, for a start.
"Pretty misleading," as Johnston put it.
Segway was totally unresponsive to queries. Retailer PB Tech did better. It had already taken back the e-scooter for battery testing before Fair Go got involved.
"It met acceptable standards considering the current conditions," Vizcarra said, adding an important caveat.
"We don't test these scooters until the battery is fully discharged, making it challenging to determine a precise final range during our testing."
According to experts Fair Go consulted, it's generally wise not to run a lithium ion battery flat.
"The more you discharge your battery, the harder you work your battery," said Dr Dulsha Kularatna-Abeywardana, a lecturer at the University of Auckland's Department of Electrical, Computer and Software Engineering.
"Running a battery right down to 100% drained is going to shorten battery life as well as its performance in the long-run."
That poses a problem for that range claim, since it relies on discharging the battery fully. Getting the 20km maximum range would have to affect battery life.
Then there is that warm summer day you need. Dr Kularatna-Abeywardana confirms it will make a difference if the air temperature is colder.
"A battery at the end of the day is a chemical reaction. As the temperature goes down, the internal resistance of the battery goes up. Quite a lot of the power output of the battery is actually dissipated within the battery, rather than being delivered to the scooter itself."
Her advice is to keep a battery topped up wherever possible - charging it back up to 100% should extend its life, though care needs to be taken not to overcharge as that also affects performance and lifespan.
PB Tech has since offered to refund the purchase price of the e-scooter, if Simon Johnston wants to return it. Johnston told Fair Go that wasn't his aim - he wanted to warn potential purchasers and encourage Segway to review its claims. He's opted to keep the e-scooter and mind how far he goes.
SHARE ME