28 November 2017

Leaf Life

As promised in my last post, we've had the Leaf for over seven months now which I believe should be long enough to provide a decently reliable review of the experience of owning it and an EV in general. So without further ado, here goes.

Topping up on electrons.
Although the industry is rapidly advancing and this post may very well be outdated within a year, the current state of EV ownership likely will require some changes for most people to provide time to accommodate reshuffling the electrons around in the battery. That time can vary greatly depending on the source of power and the options available on the vehicle itself.  While this isn't intending to be a post completely about charging or physics, I'll go over the basics along with links to further resources.

In general, there are three recognized "levels" of charging for EVs: Level 1, Level 2, and DC fast, which is sometimes referred to as Level 3. The latter is known as Supercharging for Teslas and there is an emerging ultra-fast charging option as well, though no vehicle yet available can actually use it. Back to the levels, Level 1 is standard wall outlet and basically every EV sold comes with an adapter (technically called electric vehicle service equipment or EVSE) that will plug into the wall and direct power into the battery. However, most wall outlets provide a maximum of 12 amps which means a charging rate that realistically caps at a hair
Destinations with chargers are great!
over one kilowatt (kW). While that might be fine for operating a blow dryer, the battery on the Leaf is around 24kWh*. As a result, filling its battery requires nearly 22 hours when completely empty on a Level 1 charger. As such, Level 1 really isn't a suitable charging solution for those who drive enough to require more than 10 or so hours per day of charging and/or don't have access to an outlet where they park their car.

In contrast, Level 2 charging can go much faster. The early Leafs only were able to utilize 3.3kW L2, but newer ones improved that to 6.6kW and other options such as the Chevy Bolt and VW e-Golf have the ability to utilize up to 7.2kW. My 2013 Leaf can accept up to 6.6kW which means that it is able to be basically fully recharged from empty in about three hours.

DC fast charging (DCFC), uses a direct connection to the battery to pump power into it at a much higher rate. (L1 and L2 supply AC power which must first go through the inverter to be converted to DC before it can be stored in the battery.) On the Leaf, that's stated as a maximum of 50kW, but it's faster in other vehicles such as the Ioniq Electric and of course, Teslas. However, it was also an option and unfortunately, the original owners of my car did not choose it. As such, I've been unable to use DCFC thus far and never will on this Leaf because it's not worth the trouble to retrofit.

And that lack of DCFC ability has been the single biggest point of frustration that we've had with our Leaf. While more range wouldn't be unwelcome, the fact that it takes several hours to regain any meaningful amount of charge after going somewhere has been a bigger drawback than the range itself. Instead of taking hours to charge, we would be able to recharge it most of the way in 20-30 minutes. That change would've been welcome on quite a number of trips that we've made since getting the Leaf.

That is particularly true for trips that we might make into the LA or OC areas, which are located at a lower elevation than where we live in the Inland Empire. The journey out is downhill, so we generally don't have a problem getting there. On the other hand, the car notices enough uphill on the return to make it next to impossible for us to get back home from LA on one charge, thus necessitating a stop somewhere along the way for at least the better part of an hour. With DCFC, a stop of less than 10 minutes would provide enough juice to get all the way home with some to spare.

Otherwise, aside from the annoyance at not having the ability to use DCFC for quick recharges, EV ownership has been uneventful and exhilarating. We've gone from spending over $200/month on gas to around $20/month on charging. Many of our charges are completely free, though the money we end up spending on food while it's charging perhaps evens it out. However, we've started eating at home more, which will finally provide more of the promised savings.

*Except for BMW, companies state the battery capacities (for better or worse) in kilowatt-hours (kWh). As the name implies, a kWh is a measure of how much power, measured in kilowatts (kW), was used in an hour. (One kilowatt is equal to ten 100W light bulbs and leaving them on for an hour would consume one kilowatt-hour of energy.) Instead of kWh, BMW uses amp-hours (Ah) to measure the size of the battery in their vehicles. In the same vein as kWh, Ah measures how many amps are drawn for an hour instead of how many kilowatts. Amps is a measure of current, (kilo)watts measure power. The relationship between the two is determined by the voltage, with amps x voltage = (kilo)watts. If any of the two are known, then the third can be derived from multiplication or division. For reference, modern EV systems run at 400V.

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