Drivers’ memo #6: Maximum & minimum ‘State of Charge’

Dear test drivers

Thanks for your recent data contributions to Flip The Fleet.  So far we have received 27 data uploads for last month – a very pleasing response considering many of you will have been away on holiday.  If you have the numbers for end of December scribbled down, or can guess the odometer for then to within about 100 Km, please upload the data now.  A break in the records has a trampoline effect, so you won’t get the full reports until consecutive months have been reported after a gap.

Battery charging: this month’s example of how we will use your results

Your charging routines are important for predicting potential cost savings for LEV owners, rates of battery health decay, and when LEVs will drain electricity from the national grid.  For example, best practice recommendations suggest maintaining your battery charge between 20% and 80% of capacity, and warn that stress from very high and very low charge hastens decay in battery health.  LEVs will maximise their environmental benefits if they are charged late at night and before the morning peak in electricity demand. Our preliminary test panel suggest that many drivers are not following those recommendations:

• 14 of our 29 (48%) fully electric (EV) test drivers usually charge their battery to 100% between trips (14 terminate charging at 80%, and one other at 90%)
• 10 of the 11 (91%) driving PHEV or Range Extender models usually charge their battery to 100% (one PHEV owner charges to 85%).
• 3 of 26 (11%) EV test drivers usually deplete their battery to 10% or less, and the rest usually leave 20% or more in the battery before recharging again.  Two (8%) usually deplete their battery to just 60% before recharging.
• 4 of 11 (36%) PHEV and Range Extender drivers usually use up all their battery energy between charges, and a further 3 (27%) regularly have just 10% charge left before recharging.
• 10 of 23 (43%) test drivers (the subset for whom we have full information) use a set timer to control when they charge their car (mostly to capture low overnight electricity supply costs and minimise their impost on the national electricity grid).

Some of you are charging opportunistically during daylight to maximise benefits of your solar supply, others are using office chargers during work hours, and presumably some of you need the full battery charge to meet your regular daily travel requirements.  We will explore the reasons for the variation later when a large public panel is using Flip The Fleet to see whether there is also a significant proportion of users who could be encouraged to shift their charging patterns to better fit the best practice guidelines and to minimise impact on the national grid.  Stimulating and focussing investment in education and awareness programmes is one use of your data.

1-click about EV access to bus lanes

Thank you if you have already answered our 1-click survey (most of you have!). The responses so far show an interesting divergence in opinion.

If you haven’t yet clicked an answer, please do so asap (we emailed it to you Friday 13 January – if you didn’t get it, let us know).

This time round, it would be especially helpful if you explained why you disagree or agree with the proposed policy, as we’ll collate your (anonymous!) responses and send the usual summary report as a formal submission to MoT by 1 February.

 

With best wishes

Dima and Henrik