Limitation.

On Sunday we had a very enjoyable day out.

A trip to the Museum of Flight in East Lothian, followed by a walk on the West Beach at North Berwick.  North Berwick sports only three charging outlets, one in the town centre which we managed to use.

The warmer weather made itself felt in the car’s energy consumption: about 4.2m/kWh, better than the 3.5m/kWh that has been normal through winter.  The dog was, as ever, happy strapped into the rear seat.  As I’ve said before the smooth ride and lack of vibration are a boon to the travelling canine..

The limitation was that on our return, with about 35% charge left, was the need to make an immediate , unplanned, journey to Dundee.  The limitation was the time constraint for the journey.  It would be perfectly achievable with the Leaf, with one journey Charge at Halbeath or Glenrothes on the way up and one on the way back.  Economic driving wasn’t going to be part of the plan.  But the 30 minutes on the way was a problem, so it had to be the ICE this time.

The promise of the new Nissan Leaf this year might be the solution to this.  An expected range of at least 150 miles would have meant that there would have been range left for the trip to Dundee.  A hoped for range of over 200 miles would probably have allowed the full return journey.  I’ve read and in conversation heard that people would consider an EV once range is past 200 miles.  In nearly a year of ownership, this is the first time that this has been an issue.  If there hadn’t been an ICE available, then we would have made the journey in the EV, but would have had to accept the limitation of charge times.  To me at least this illustrates that a 200 mile range is a convenience issue, not a true need for the majority of users.  I’d be interested to hear what the potential impact on the battery chemistry is for a larger battery that is mainly floated around 70 to 100% most of the time. There is a definite guideline that it’s  generally a good thing.

Lithium batteries are generally reckoned to be good for around 500 full discharge recharge cycles, 100% down to 0%.  Most users don’t do that, whether by planning or simply allowing for maximum range when they set out again.  The number of duty cycles shoots up past to 1200 – 1500 with only a 50% depth of discharge. (500 full cycles using EPA figures is 53500 miles, 1500 half cycles is 76000 miles.  Then there are Leaf Taxis with 155000 miles on the clock, nothing but Rapid charges, and only 15% capacity lost)    Many users report that when the battery starts aging, a few DC Rapid charges seems to instill a recovery

Battery chemistry and Battery Management Systems are evolving, so things do change. For example, the early Leafs’ requiring ‘Long Life’ charging regimes, not the case on newer models.  Tesla forums for daily use seem to offer loose guidance to an 80% charge limit, to be exceeded for days where a longer drive is planned, with a nominal sweet spot slightly lower.  But that’s all hearsay to be fair.  I’m still waiting for my first battery report from Nissan, I’ll see what it says about my charging and driving regimes.

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njel13

Engineer, EV driver, dog owner.

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