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EV leafspy in hand


There has been a steady increase in the number of EVs driving on New Zealand roads, with 1,230 used Nissan Leafs registered so far this year and more on the way. There are now over 5,000 EVs and plug-in hybrids registered in New Zealand.

What's crucial to know about EVs?

Many buyers and dealers are still in the early stages of understanding one of the crucial aspects of an EV – its battery.

For Leaf owners, the state of health (SOH) reading is one of the keys to knowledge.

The SOH shows the current maximum charge holding capacity which determines how far the EV can travel between charges. SOH slowly declines as the car gets older so its range drops gradually throughout its life. So far, only the Leaf records its battery state of health, although other EVs report on other battery data.

There have been some complaints to dealers from buyers whose Leaf after-sale SOH readings dropped off significantly soon after purchase. One such case is heading for the Motor Vehicle Disputes Tribunal.

EV Henrik and Dima with a Nissan Leaf


Someone who is researching the issue is Henrik Moller (pictured above) – an environmental scientist and Professor Emeritus at Otago University’s Centre for Sustainability. He has sympathy for dealers who have had complaints based on readings of a Leaf battery’s SOH.

“I have a 2015 Nissan Leaf and its SOH has fluctuated between 94 and 100 percent in the past two months. It seems to relate to how much charging you do, and whether you run it right down. So the readings after leaving the car yard may be quite erratic and any drop in SOH does not necessarily mean the dealer exaggerated the health of the battery at time of purchase.”

He says dealers should be careful not to keep the battery charged at 100 percent capacity while it’s on the sales forecourt, especially if it rests there for several weeks. “It’s much better to keep it charged between 40 to 60 percent – and explain to the customer that this is better for the battery when it’s not being used.”

Ideally, for cars that are driven most days, the battery should be charged up to 80 percent of capacity and recharged before it reaches 20 percent.

Henrik Moller and Dima Ivanov, a specialist in using industry benchmarks to improve business performance, have set up a community research project Flip The Fleet to gather data on Leaf battery SOH and vehicle performance from New Zealand EV owners. “Similar studies are going on around the world as this is very new technology and we need to know how the batteries perform over time in different environments,” says Henrik.


Finding out an EV battery’s SOH is relatively simple using a plug-in dongle (OBD2) that connects via Bluetooth or WiFi to a cellphone or tablet using a Nissan Leaf app LeafSpy, or EVBatmon for Mitsubishi models.

Different car makes use a range of technology or apps to record the battery’s charging history and other information.

Henrik and Dima encourage car dealers to direct all EV buyers to the Flip The Fleet website where new owners can join the study and access discussions on battery performance and EVs in general.

A preliminary table of Nissan Leaf SOH measures is already available on the site for prospective buyers to compare scans of the EV they are interested in buying. However, the study needs more owners and dealers to participate to keep improving benchmarking comparisons.

Henrik says it's important dealers take the time to understand all aspects of the new technology. “I have been told of some distressing examples where a dealer did not supply the proper charger and cable and this is very dangerous; it could even cause a fire.”

EV Carl Barlev


Support for EV car buyers is coming from small companies such as Blue Cars which provides a range of services and parts, including the import and sale of New Zealand-rated charging equipment.

Managing director of Blue Cars, Carl Barlev (pictured above) says he is importing chargers from Sweden as his early experience with Chinese-made chargers was not good.

“Of the first six I bought, four stopped working within three or four months.”

The New Zealand Transport Agency website has good information on charging equipment. Carl says electricians are not yet up to speed with installing the right charging sockets in people’s homes. “There are some misunderstandings, and regulations are still catching up with industry knowledge and best practice.”

One of the crucial thing to know with portable charging cables is what current they are rated for.

“Both the plug on the cable and the home wall socket must be properly installed and suitably rated depending on the maximum current they could supply. For cables that deliver up to 8 amps, a 10 amp plug and socket can be used; for cables that draw up to 16 amps, we recommend a blue caravan plug and matching socket. The use of 10 amp and 15 amp plugs on charging cables drawing more than 10 amps is one of the biggest fire risks.”

Carl also has words of warning about the use of portable chargers. “They’re fine to use occasionally when you’re away on holiday, but if you are using one as your main source of charging then you should consider upgrading to a fixed installed unit. These are not only a safer option, but are also more secure and less likely to get stolen. They also remove the risk that somebody may not connect the plug fully, which is another fire risk when using portable chargers.”