Drivers’ Memo #16: your award, an emission reduction milestone, battery health, tyre pressures and load!

Kia ora koutou

Take a bow everyone!  Your courage, knowledge and commitment to sustainability as early adopters of EVs were recognised in Flip the Fleet winning the ‘Smarter Transport’ award in last night’s Sustainable Business Network Awards – see https://sustainable.org.nz/2017-nzi-sustainable-business-network-awards-winners/.  Actually, you were also shortlisted along with six other category winners in the NZI Greatest Contribution to a Sustainable New Zealand (Supreme Award), but that was awarded (very fittingly) to NZ Post.  The photograph below is of Vasily (developer) and Tatyana Levshina (tester, left) who, along with Dima Ivanov, have developed and tested the software that carries your project along. Then there’s me and my amazing wife Fiona, who has been extremely supportive of the “few hours” that I, as we all, have invested into Flip the Fleet. The citation said: “The judges were impressed by their robust analytics and metrics and their dissemination of this information. They are enthusiastic Electric Vehicle owners who are innovatively tackling a barrier to move the market to EVs – what a difference Flip the Fleet will make!”.  Thank you Opus International for sponsoring the Smarter Transport prize, and NZI and the Sustainable Business Network for their long-term work to support sustainability in all it’s forms in New Zealand.

A million small gifts to your grandchildren: We noticed from the national extrapolation reports on the ‘NZ Data’ page of your dashboard showed that EV’s will avoid 1 million kg of CO₂ emission this month.  This milestone gave us an excuse for an added Media Release this month – all part of trying to keep the benefits of EVs in the public eye.

November’s data analysis and 1-click survey featured battery health and the way it gradually declines in 24 kWh Leafs.  Daniel Myall fitted a statistical model to 777 battery ‘State of Health’ (SoH) measurements from 147 cars collected over 6 years.  We still need a lot more data (keep those LeafSpy reports coming please), but so far, the modelling shows:

• age of the car is main variable associated with battery SoH
• range declines at an average of 2.0%-4.0% per annum because of battery decay
• decline is slower in the first few years compared to later
• no evidence of different rates of declines in battery State of Health in Gen1 and Gen 2 (24kWh) Leafs
• large variability in rate of decline in SoH between EVs of the same age
• no evidence of impact that more fast charging increases decay rate
• no evidence that total distance travel affects SoH (once the year of manufacture has been taken into account).

The modelling shows that 24kWh Leafs will still be able to travel 85 km on a single charge when ten years old, well in excess of the average of the average daily travel of cars in New Zealand. Battery refurbishment costing between $2,000 and $5,000 will then reboot the EV’s range. These costs are way less than the money saved on fuel and reduced maintenance costs in the interim. The newer and larger EV batteries will last much longer than these earliest models, so battery degradation is a manageable and decreasing part of normal maintenance and repairs of electric vehicles.  A media release on these results is at https://flipthefleet.org/2017/media-release-electric-vehicle-batteries-lasting-well-far/

As usual, your detailed comments in November’s 1-click survey demonstrated detailed knowledge, pragmatism and a long-term view (you can read the comments in full at https://flipthefleet.org/2017/1-click-survey-13/).  Battery capacity decline was seen as an acute problem only for the early models and for people with greater than normal daily travel range requirements.  For many it is not an issue at all.  An urgent national priority is to grow NZ’s fledgling battery refurbishment industry, partly to build confidence of prospective buyers, but also to support early adopters of smaller EVs. Others called for research to establish better SoH measures, and communication of some real case studies of battery refurbishment to help assure prospective buyers that rebooting your battery is just a normal part of long-term maintenance and repairs.

A Dunedin EV community experiment: Flip the Fleet made some of its Dunedin members earn their BBQ last weekend. They drove in a big circle swapped sandbags between their cars to simulate the effects of extra passengers  on efficiency (km/kWh) – see  https://flipthefleet.org/2017/effects-load-eco-stetting-route-efficiency-dunedin-ev-community-experiment/.  It turned out that added load reduced efficiency in a very hilly and winding route where the cars had to slow and accelerate a lot, but had no apparent effect when travelling steadily along a motorway, even up and down hills.  Intriguingly, the ‘Eco’ setting resulted in lower efficiency than ‘Drive’.

Please check your tyres regularly: Before sandbagging their cars, the Dunedin EV drivers also checked tyre pressures – https://flipthefleet.org/2017/many-us-inflated-tyres/.   It turned out over half of them were under-inflated, at least according to the Leaf recommended pressure of 36 psi.  Getting the pressure right for your size and make of tyre can greatly improve your efficiency and secure safety.

This month’s hint to get the most out of Flip the Fleet’s dashboard: You can select the benchmark comparisons you want by clicking on the greyed-out items in the key to right of the graph. For example, click on the ‘Mean’ label in the key (to the right) to make it appear. You can also click on any of the highlighted keys to make them disappear. Go on, play with the buttons at the top! You can’t break anything and the default settings will always restore when you next open the report.

Gathering momentum: We now have 470 EVs enrolled and the data are beginning to gain scientific authority.  We still are short of sufficient PHEVs in general and would love to enrol some more Hyundai Ioniqs and the other new EV and PHEV brands that are appearing.  Each time a new brand appears we have to start from scratch to build a picture of where they fit in the spectrum for efficiency, fuel savings, return on investment etc. Please spread the word and invite your EV friends to sign up.

Cheers and thanks for participating.

Dima, Daniel and Henrik