Level 3 Charging stations

How many level 3 charging stations do you need for average drivers to use an EV to drive as far as they would a gas car?
Let’s make some assumptions and do some calculating.
Suppose the average driver drives 12000 miles ( thats 33 miles per day ) per year.
And let’s say he has an electric vehicle with a real range of 100 miles.
Assume 2000 of those miles are on trips longer than 100 miles.
Assume those 2000 miles happen on 7 long trip days ( 4 at 200 miles, 3 at 400 miles )
The average distance for the other 358 days is now 28 miles, all the charging for that happens at home overnight ( even plugged in to a 110V outlet ).
On those long days this driver will need to recharge 1300 miles worth away from home ( 4 x 100 and 3 x 300 ) because he leaves home full.

Let’s assume that the level 3 charger is somewhere between a 50kW and 75kW charger and can charge 100 miles of range in 30 minutes.
You need a level 3 charger between you and your destination when you exceed the 100 miles.
Now lets assume that 80% of those miles happen between 8am and 6pm on friday, saturday or sunday during 24 weeks of the year ( april-september )
That means they will happen on any 10 hour span of 72 possible days, a total of 720 hours.
80% of 1300 is 1040, which yields 5.2 hours of charging.
Put it together and 1 level 3 charger would support 277 EVs. ( Yes you want to add capacity to avoid clumping problems, but the more you add in total, the less this is a problem )

If the car had a 200 mile range, the amount of charging needed would drop to 600 miles worth ( 200×3 ).
And 80% of the 600 is 480 yielding 2.4 hours of charging.
One level 3 charger would support 600 longer range EVs.

It’s about 1300 miles between Seattle and San Diego.
If we put in 39 locations ( one every 33.3 miles ) and each location had 2 plugs, that would be 78 charge plugs.
Those 78 plugs would support 21600 EVs evenly distributed along those 1300 miles and driving along that corridor.

As the number of EVs goes up, we would need to add more charging units to add more plugs.
Of course the EVs are not evenly distributed so you would add more plugs where the usage warranted it.

My point isn’t about localized demand and clustering ( save it for another post ), it’s about the diminishing investment we will have to make in level 3 chargers as the technology improves.

As the battery technology improves and the cars carry bigger batteries by default, the fewer level 3charging units we will need along the highways.
When the average car has 200 mile range instead of 100, those 78 charge units will support 46800 cars.
When the average car has a 300 mile range instead, those 78 charge units will support 93600 cars.
When the average car a 400 mile range, we wont need any charge units in the scenario where you drive 400 miles max in a day.

I think while electric cars are young we will need to aggressively add plugs.
Battery technology is improving fast, it is possible that by 2014 the average new electric car will have a 200 mile range and by 2017 it will be 300 and by 2020 it will be 400.
If at 2014 there are 100,000 100 mile range cars, we would need about 360 charge units.
If at 2017 there are 350,000 cars ( 100,000 with 100 mile range, 250,000 with 200 mile range ) then we would need about 777 charge units.
If at 2020 there are 1,000,000 cars ( 100,000 with 100 mile range, 250,000 with 200 mile range and 650,000 with 300 mile range ) we would need about 1450 charge units.
After 6 years, 10 times as many cars and only 4 times as many charge units needed.

If that is the case, even with fantastic growth in electric cars I would think the num-ber of level 3 chargers we need will peak at 2020.
After 2020 as more people go electric and discard their ICE cars, the existing level 3 chargers will be sufficient for the super rare event of driving more than 400 miles.

Once cars have 400+ mile range, then the equation changes. You will no longer think much about stopping at level 3 charge plug along your drive.
( Although if there is a restaurant/rest facility next to it, you certainly will want to, as you have become accustomed to civilized travel ).
If you intend to put together back to back days of 400+ mile travel, you will want a level 2 charger at your hotel that can charge your car overnight.
But those are trivial compared to level 3, a level 2 charger is just a box plugged in to a 50-100 amp breaker.


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