Saturday, October 5, 2013

DC Quick Charge: Better Than a Bigger Battery

A BMW i3 charges at the first public SAE CCS quick charge station open in the US. 

The first public DC quick charger in the US that uses the SAE-endorsed Combined Charging System (CCS) opened this week in San Diego, CA. It's located at the Fashion Valley Mall and uses a dual connector quick charger called a "Freedom Station" by EVgo.

The i3 will have a DC quick charge option that the customer can elect or pass on. The price has not been set yet but the speculation is it will cost somewhere between $750 and $1,000 extra. Having the option will allow you to recharge the car to 80% in about 20 minutes. This is an incredible advantage to have in an EV, since charging times are really what limit EVs like the i3 from being able to cover hundreds of miles without much inconvenience. Of course you can get an EV with a huge battery like the Tesla Model S which will allow you to drive a couple hundred miles between charges, but to be able to really cover long distances without much inconvenience, DC quick charge (or battery swap ability) is really needed. 

Standards War

SAE & CHAdeMO side by side
Tesla understands the absolute need for quick charging on pure electric vehicles and is rolling out their own network of DC quick chargers they call Superchargers. Since Tesla uses a proprietary connector nobody other than Tesla customers will be able to use their network. Nissan uses a different connector called CHAdeMO (short for CHArge de MOve or charge for moving) which was developed by Tempco (yeah, the power utility that runs the Fukushima nuclear power plant) for quick charging electric vehicles in Japan. When Nissan came out with the LEAF, the SAE hadn't yet endorsed a DC quick charge connector for the US so Nissan had no other option but to use the CHadeMO connector on the LEAF for quick charging, not that they wouldn't have anyway. Then, once the SAE endorsed the CCS connector, BMW, along with Audi, Chrysler, Daimler, Ford, GM, Porsche all agreed to use it on their plug in vehicles, when they eventually make them. I'm not going to go into why one is better than the other, or why some manufacturers chose one over the other here. There are plenty of articles on the internet that discuss this at nauseam; just do a simple search and you'll find them. I will say that I've talked with a few BMW engineers about this and they all basically told me there was no decision to be made. That the SAE CCS system is so technically superior to CHAdeMO, especially for future applications, that they wouldn't have even considered it. 

Personally, I really don't care which "standard" my EV has, as long as there are chargers out there for me to use. I've held both and even plugged both into cars and the SAE is a little lighter and less bulky and you only need a single charge port on the car so I tend to favor it, but honestly, I would be fine using CHAdeMO if there were chargers installed in my area and there aren't. At the i3 premier in July a BMW program manager asked me how much would I be willing to pay for the DC quick charge option. I suspect the price for the US market hadn't been finalized yet. My response was, "That depends" eliciting his curiosity. I followed it up by saying right now I won't pay a penny for a DC quick charge option because there are no chargers within driving distance of my home. However let's say there were a couple here and there in my general area, then I'd pay about $500 for it. And if there were a couple dozen of them in northern New Jersey I'd be willing to pay $1,000 for it. 

I know we are many years from having DC quick chargers in accessible, convenient locations like gas stations but I also believe that day will eventually come. The West Coast has a huge head start over the rest of the country and probably has as much as 70% of the Superchargers, ChadeMO and now CCS stations installed in the entire country. Plus, with the recent NRG settlement California will get 200 more DC quick charge stations, most being dual connector (CHAdeMO and CCS) units. Tesla currently has 24 Superchargers installed and an aggressive plan to cover the rest of the US in a few years. Nissan meanwhile has committed to installing hundreds of CHAdeMO stations in the US although they haven't delivered much on that promise yet. Outside of California's NRG settlement the future is unclear how and when we'll get the SAE CCS stations installed. Without any clear plan for the area you live in, I think it would be foolish to pay up to $1,000 for the option if you don't even know if you'll ever be able to use it. I have a friend that bought a LEAF in 2011 here in New Jersey and paid for the CHAdeMO option but nearly three years later he has never been able to use a CHAdeMO station because there are none within his range. 

I had the opportunity to talk with a BMW manager at the i3 premier about DC Quick charge infrastructure and one of the questions I asked was will the BMW i dealerships be required to install a DC quick charge station. I thought that would be a great way to at least begin the roll out of compatible DC quick chargers for the i3 so customers will at least have their local dealerships to fill up quickly at. They could also look for BMW i dealerships along the route of their long trips and since most dealerships are on highways, the locations would probably be good ones. Unfortunately that isn't going to happen. The dealers will not be required to install DC quick charge stations, but they will be "encouraged to." Personally I'd like to see BMW "encourage" them by offering to supply them with the DC charging station for free, as long as they pay to install, maintain it and have it available for use even when the dealership is closed. The dealerships will however be required to install multiple level 2 charging stations though which is a start, but really doesn't help out with longer road trips.

"Quick" Level 2 Charging

Is there such a thing as quick level 2 charging? While level 2 charging (240v) isn't necessarily quick, some cars do charge quicker than others. The Model S is the king (in the US at least) of L2 charging as it can charge at a rate of up to 20kW with optional dual onboard 10kW chargers. However the real L2 charging champ is only available in Europe. The Renault ZOE's onboard "Chameleon charger" can charge at up to 43kWs! On the other end of the spectrum is the Chevy Volt that is restricted to 3.3kW charging. However since the Volt has a much smaller battery than a Model S, it can actually fully charge in about the same time as a Model S can with it's massive 85kWh battery. The i3 will be able to charge at up to 7.4kW, and since it has only a 22kWh battery, it can fully charge in under 3 hours. This delivers a rate of about 30 miles of range per hour when charging from a 240v 30 amp level 2 charging station. That's a good improvement from my ActiveE, which returns only 15-18 miles of charge per hour. BMW is quick to point out how fast the i3's battery can be replenished while charging on L2, and while it is better than any non-Tesla EV here in the US, it still pales compared to the 80 miles of range you can get in 20 minutes on a DC quick charger.

Bigger battery vs DC quick charge 

The i3's 22kWh battery will allow for 80-100 miles or range in every day driving conditions, and up to 125 miles if the more efficient ECO-Pro+ driving mode is selected (Says BMW). So if range is so important, why not just slap a 40kWh battery in there and call it a day? The i3 would get about 200 miles of range and you wouldn't need quick charge, right? Wrong. Tesla uses enormous battery packs and they still realize they need a DC quick charge network to really make their electric cars viable to the broad public. Even with 200 to 300 mile range their customers want to be able to quickly recharge so they can drive long distances. The truth is, no matter how big your battery is and how far you can drive on a single charge, people will always want more range and quick charging. This is way BMW is offering the range extender on the i3. They know that it's going to take years for a comprehensive DC quick charge network to be built out, so until we have a robust infrastructure in place, the range extender will be a very popular option and will allow the owner to drive as far as they need on the few occasions they need to travel long distances. For daily use they won't use any gas, as the ~100 mile range should be more than enough for the vast majority of the time, yet they still have the flexibility of being able to cover hundreds of miles should the need arise. I believe the range extender becomes obsolete once we have adequate quick charge infrastructure in place. In fact, large Tesla-sized batteries won't be necessary either. Why carry the additional weight around and pay for a huge battery pack when you can use one half the size and just charge it quickly when the occasional need arises? The main reason EVs cost more than conventional powered vehicles is the cost of the battery pack. A smaller pack combined with readily available quick charge is clearly the way to go, however getting the infrastructure in place is the 800 lb gorilla in the room. It's not just going to happen without the support of the manufacturers. Tesla and Nissan seem to be doing their part, will BMW and the others that have signed up to use the SAE CCS standard do their part? Only time will tell.
The BMW EV infrastructure team was well represented at the grand opening event for the first public CCS quick charging station. Will they continue to be involved in assisting CCS station deployment, or wait by the sideline and watch?


  1. I fully endorse the position that fast charging is much better than higher capacity batteries, but not because I want to drive an electric car on a long trip during any one day. When the next generation of battery shows up in i3s in a few years, I'm hoping the cheaper and lighter batteries (for the same capacity) will translate to a cheaper and lighter i3 having the same capacity 22 kWh battery. With the same battery capacity, a lighter i3 will go farther, have better performance and better handling. Most people will still drive less than 40 or 50 miles a day. If fast charging is available, then people can make the longer trip with a short "filling station" stop.

    BTW, Tom, page views on the i3 blog are about to overtake those on your ActiveE blog -- passing the torch, as it were.

    1. I noticed the views. It's funny because my ActiveE blog just passed my MINI-E blog in views last week and in a couple days this blog will pass the ActiveE. Nearly 300,000 page views combined. I would have never thought that when I started doing this a couple years ago. :)

  2. I also support the format CHAdeMO SAE Combo front, although there are some who try to attack Frankenplug calling it, because I think it has many more advantages than the CHAdeMO. But at the time of the installation of DC Quick Charge, the fact that so many manufacturers associated perhaps be counterproductive when installing new DC Quick Charge, because if BMW builds and pays new DC Quick Charge other manufacturers free taken advantage of that investment, or if it does also build GM is the same with BMW. So maybe the deployment is slower than in the case of Tesla or Nissan, where they know that their money are going to be charging almost exclusively for their cars.

    1. sorry for my english but Google translate and I speak bad english.

  3. "On the other end of the spectrum is the Chevy Volt that is restricted to 3.3kW charging."

    Actually, on the other end would be the Toyota Prius Plugin with 2.1kW L2 240V charging.

    1. vdid: It's funny because the PIP actually has a 3.3kW onboard charger, but the car won't let it charge at it's maximum rate.

      I use the Volt because the PIP is hardly a real electric car. The Volt definitely is and I think people recognize it as an EV more than they do the PIP.

    2. I have the PIP and the slow charging rate and the ACTUAL miles I get per charge has been my biggest disappointment. My commute is very short but I actually drive my PIP LESS because I only get 9-10 miles on a charge. I still average 200 MPG but I expected to get 15 miles at least and be on electricity ALL the time. This is the primary reason I'm switching to i3 REx.

  4. Great post Tom!

    I differ on the opinion of battery size vs. quick charging though. I agree that both are needed, and the ~25 kWh battery w/ a city network of quick chargers is sufficient for local driving. I have been lucky enough to be using this strategy in Houston (LEAF + CHAdeMO) for over two years now.

    But for road trips, I would not imaging taking my LEAF from Houston to Dallas, even if there was adequately spaced chargers. In my example it is a 240 mile trip. Starting with 80 miles of (ideal condition) highway range and stopping for 80% quick charges, you would be looking at three charging stops.

    That is realistically 1.5 hours of stopping/charging for 3.5 hours of driving time. The larger pack of the Tesla can do the trip in one 15 minute stop (theoretically no stops) very similar to an ICE trip. For road trips, I think Tesla has the right formula: 3 hours of driving and 30 minutes of charging.

    1. Hi Josh, thanks for commenting. Sometimes I admit I live in a bubble. Here in NJ a 240 mile journey is not nearly as common as it might be in Texas. In fact, I don't think I've driven 240 miles in one direction more than five times in the past ten years.

      How often do you drive that far? Lets say DC quick chargers were everywhere, like gas stations. Yes, a long 240 mile trip would take 1.5 hours longer but if you only needed to do that two or three times per year I still think you are better off not buying a huge battery and dragging it around with you everywhere you go making the car less efficient all of the time you drive it.

      I'm all for longer range EV's. But I don't think everyone should buy them. You are wasting your money and consuming more energy than needed if you buy a 300 mile battery and only drive more than 150 miles in a day a few times a year. I really like Tesla's optional battery size approach. If the i3 came standard with the 22kWh pack but offered an optional 30kWh battery I think they wouldn't have had to bother with the range extender. I know I would have gladly paid an extra $5K or so for a larger pack.

  5. Thanks to another forum, is the supposed document for eVgo's California only settlement. Page 2 has their goals (for their 200 stations).
    "Each of NRG’s Freedom Stations will include
    chargers that are compatible with CHAdeMo and
    SAE standards.
    eVgo Freedom Station sites will be completed in as
    soon as 4 years with yearly installation goals of:
    o 20% in year 1
    o 30% in year 2
    o 30% in year 3
    o 20% in year 4"
    Problem is, I don't know when/whether time 0 (year 1) has begun. is the AFAIK, the first and currently only eVgo station w/both CHAdemo and SAE J1772 CCS. Looks like opened on Sept 30, 2013.