The Leaf is not always 250 Wh/mile (4 mi/kWh). It can be under comfortable
weather and clean roads, but in deep cold, or slushy highways, with the
resistance heat on, even with smooth driving, it can exceed 350 Wh/mile
(2.9 mi/kWh). Aggressive high speed driving in rainy conditions with the
heat on can bring it to 360 Wh/mile (2.8 mi/kWh).

L2 6.6 kW charge rates translate to about 25 miles range per hour for the
Leaf. That's quite an improvement over L1 1.4 kW 4-5 miles range/hour or L2
3.3 kW of 12 miles range/hour.

There is a relationship between trip distance, pack size, and useful charge
times. ICE vehicles have an advantage on 'pack' (tank) size and 'charge'
times. Trip distance is a function of the owner's needs, and in some cases
but not always, planning.

Vehicles with large packs can more easily get by with slower charging for a
greater number of trips, as long as the pack's remaining capacity is always
greater than the length of the next trip, and on average there is
sufficient time allocated in the schedule for it to be plugged in to 'catch
up'. A 200 mile range EV could run a charging deficit for several days and
still be able to make a 100 mile trip without stopping along the way.
Spending half a day/4 hours at the destination on L2 6.6 kW restores this
EV to 100 miles range for a return trip. Visits in half day category
include spending the evening with family/friends, some office
schedules/site visits, museums, zoos, and some amusement park trips. These
EVs really only need L3 fast charging only on the extended road trips that
go beyond their pack capacity, and because they have a large pack, those
trips are quite likely few and far between.

Vehicles with small packs need fast charging in more situations to remain
useful. 1 hour stops at a location are not uncommon: movie theater,
shopping mall, dentist, and may be 20 miles from the next stop/home. A 60
mile range EV needs to keep it's charge level up, and have access to fast
charging to make the same 100 mile trip possible in a reasonable timeframe.
That 60 mile range EV will need an in between stop with DC fast charging to
make the 100 mile trip, unless waiting 2 hours somewhere en route is
acceptable. These EVs run into their pack capacity limits much more
frequently than the longer range models, and on road trips will need that
many more fast chargers to stay useful.

Lastly, people are more accepting of waiting at either end of a trip than
in the middle; this in turn affects the charging needs.



On Wed, May 13, 2015 at 7:57 PM, Jamie K via EV <ev@lists.evdl.org> wrote:

>
> So I take it you aren't driving an electric car and using L1 at home to do
> all or most of your driving?
>
> For us it isn't hypothetical or theoretical. And for anyone, please be
> clear that a "typical day" is not a relevant metric for range requirements.
>
> It's the outliers that you have to accommodate. Don't lose sight of that.
>
> Your data about 10,000 miles being 40 miles per day is again getting hung
> up on the average. The average is not the appropriate consideration for
> range, some days will be less, some more, and a savvy (and ultimately
> satisfied) EV buyer must consider the latter cases (or have another vehicle
> that can handle them).
>
> The average doesn't include trips to grandma's in the next town over, or
> the emergency trip to a child's school, or an extra trip home to retrieve a
> forgotten item, or going out again after work, or rushing to a hospital, or
> accommodating any other part of life that may come up occasionally that,
> while above the irrelevant average, are important and maybe even critical.
>
> Some days we might not drive at all, some days we might charge multiple
> times and cover longer distances. On those days, with the 6.6kW charger, we
> are back in business in an hour or so, four at the most. whereas if we were
> at the mercy of slow L1, multiply that times five.
>
> Realistically, on those days we can't wait 5-20ish hours for each
> additional charge. On those days, we can't have the car be out of service
> for anywhere close to that long, that would make it unusable.
>
> If the goal here is to have electric cars be widely adopted and not just
> niche vehicles, flexibility for the busier days is key. Faster charging
> makes that possible. On days when it's not important, no problem. On those
> days when it IS important, what a relief it is to have a usable car.
>
> The top selling EV is the Nissan LEAF, and they get it. They offer 6.6kW
> L2 charging including at home, and much faster L3 charging, both of which
> make our 2013 SV usable for our situation, for everything but longer road
> trips. They are also working toward longer range cars which will also help
> EV adoption, as will the next round from Tesla, GM and hopefully others.
>
> Of course our situation is not everyone's situation, but I wouldn't
> dismiss it as particularly rare either. Everyone's situation is different
> and potential EV owners have to evaluate range based on their own range
> needs (but not merely their average range needs).
>
> Talk to anyone who started out with only L1 (usually to save money) but
> eventually added L2. An EV with faster home charging becomes much more
> flexible and useful and creates happier EV drivers, which helps
> word-of-mouth promotion and growth in the EV market.
>
> Cheers,
>  -Jamie
>
>
>
> On 5/13/15 6:04 PM, Ben Goren wrote:
>
>> On May 13, 2015, at 1:44 PM, Jamie K via EV <ev@lists.evdl.org>
>> wrote:
>>
>>  I'm coming from a perspective of practical experience with an
>>> electric car as our main vehicle.
>>>
>>
>> The big factor you left out is daily driving mileage. If you're
>> putting 80 miles a day on the car, yes, L1 is probably borderline at
>> best for you. But, for most people, half that is an unusually busy
>> driving day. Not all people, of course, by any means...but most.
>> Remember: most automotive warranties are in the range of 10,000 miles
>> / year, which is equal to 40 miles per day, five days a week, fifty
>> weeks a year; if you're doing more than that, you're probably beyond
>> your warranty's coverage, which most people don't do.
>>
>> And, with a 250 Wh / mile vehicle (such as the LEAF), 40 miles is a
>> mere 10 kWh and well under 7 hours at L1 rates.
>>
>> If it takes less time to charge the car for an entire day's worth of
>> driving than it does to get a night's sleep, any sort of argument for
>> faster charging as the normal mode is damned hard to make.
>>
>> b&
>>
>>
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