Key To Mass EV Adoption: Faster Level 2 Charging

By · April 25, 2013

For years, automakers have been trying to figure out what an electric car needs to offer before an average consumer will make the switch from gas to electric. Longer range and a competitive sticker price would help. But there's also a strong argument that speedy daily EV recharging times will make the biggest difference.

I’m not talking about rapid recharging with an expensive direct current charging station. What I mean is improving the speed of the onboard charging system included as standard with every electric car.

Nissan LEAF Charging

For the past couple years, Nissan LEAF owners have endured charging rates that add around 10 miles of range in an hour.

3.3 Kilowatts Is Too Slow

To keep manufacturing costs down, and to keep cooling requirements at a minimum, cars like the 2011 Nissan LEAF and 2011 Mitsubishi i came with 3.3-kilowatt onboard chargers as standard. That equates to a rate of between 8 and 15 miles of range added per hour of charging, depending on state of charge and the battery pack’s temperature.

While sufficient for overnight charging or charging at work, 3.3-kilowatt charging isn’t attractive to first-time electric car drivers used to refueling their car in a few minutes at the gas station.

Full-Scale Quick Charging Is Too Costly

Solutions like the CHAdeMO direct current rapid charging system favored by Nissan and Mitsubishi—as well as Tesla’s Supercharger network—offer a much faster recharging solution than onboard chargers. At 50 kilowatts, CHAdeMO compliant cars can recharge from empty to 80-percent full in as little as 30 minutes, adding between 50 and 60 miles of range. Meanwhile, Tesla’s Supercharger system can add up to 150 miles of range in the same time, thanks to 90 kilowatts worth of charging power.

Here’s the rub: while rapid charging systems are fast, they are also costly to install since they require high-power three-phase supplies in order to operate. The compromise between speed and cost lies somewhere in between the slow 240-volt Level 2 and expensive DC Quick Charging.

Onboard Flexible Charging

Enter Renault’s Zoe, Mercedes Benz’s Smart ForTwo ED, and now Volvo’s second-generation C30 electric prototype.

With onboard chargers capable of taking any type of power feed from 3.3 kilowatts single-phase, up to 22-kilowatts three phase, all three vehicles can recharge quickly from inexpensive European public charging stations without requiring a expensive, cumbersome, external chargers.

In the case of the Renault Zoe, even faster charging is possible, but only at the 43-kilowatt AC equivalent of the rapid charge stations championed by Nissan, Mitsubishi and Tesla.

The U.S. Solution Already Exists

The J1772 specification that every U.S.-market electric car uses allows for charging at up to 80 amps at 240 volts, provided of course that the onboard charger and car is capable of receiving that much power. Moreover, that's 80 amps at 240 volts single phase, or 19.2 kilowatts, making it easier to install than the European three-phase system. But while the specification allows for 19.2-kilowatt charging, no cars on the market today support that high a recharging rate.

Toyota RAV4 EV Charging

The Toyota RAV4 EV uses a 10-kW charger that is compliant with the J1772 standard. That adds 30 or more miles of range in an hour. Everyday charging can go even faster.

At the moment, the 2013 RAV4 EV is the fastest-charging J1772-compliant EV on the market, thanks to its Tesla-derived 10-kilowatt onboard charger. Meanwhile, 2013 models of Nissan LEAF, Ford Focus Electric, Fiat 500 EV and Honda Fit EV all offer 6.6 kilowatt charging, the equivalent of adding around 30 miles of range per hour of charging.

While 30 miles per hour charged is better than 15, it is still sluggish compared to what the J1772 would allow, and what drivers would like to see. Double the power of J1772 charging included as standard in EVs to between 14 and 16 kilowatts, and it becomes possible to recharge an electric car at a speed of around 60 miles range per hour charged. That makes it possible to recharge an electric car as quickly as it is drained, making trips beyond the range of a single charge much more practical.

This approach does not require the J1772 Combo connector. The J1772 specification already allows for high-power, single phase charging.

Now it’s time for automakers and charging providers to make use of that full specification in the next generation of EVs and charging stations. And then watch the market of potential EV buyers react favorably to news that fast, practical and affordable electric car charging is part of the deal.


· · 4 years ago

I'm not sure if I buy into the premise of this article. Is faster L2 charging really the biggest hindrance? Sure, it's a cheaper way to reduce charging time, but it's still not fast enough for a road trip scenario. If I am going to hop on the highway and drive for 250-300 miles (which I do frequently), I am NOT going to stop three times, for close to an hour and a half each time. I would only make such a trip in a Tesla where I can supercharge for about 15 minutes on the way.

On the other hand, if I am out and about for a day of chores (i.e. stopping at locations for a while, without just passing through), 19.2kW is far more power than I need.

Another thing worth noting is that there are two versions of the J1772 standard. The spec was originally released in 2001, limited at 240V / 32A, which is 7.68kW. It was upgraded in 2009 to support 240V / 80A, or 19.2kW. It seems most car companies are sticking with the earlier version. Also noteworthy is that many (most?) of the installed L2 infrastructure today only supports up to 32A, but that's easy to remedy NOW while it's still growing...

Oh, and btw, Tesla offers dual on-board chargers on the Model S, which would accept up to 20kW, more than the 19.2kWh of the J1772, so it is incorrect to say that no cars support the full rate.

· · 4 years ago

I agree.

As an owner of Tesla cars that support 70+amp charging for the last three years (both Model S' that have the 20kw option and all Roadsters DO support this so its incorrect that no current cars offer this) I can say that I got along just fine on long road trips using the several 70amp 240volt J1772 stations sprinkled around California, especially along highway 101 between Los Angeles and San Francisco. I've traveled between the two regions without using fast/super chargers multiple times--it just requires more patience, but is not impractical and is dramatically better than relying on the 30amp stations found most places.

Fast charging is more convenient, yes. But to your point, for spots where this isn't as easy to get installed, it's very easy to put in an 80amp J1772 station (19.2kw) at virtually any home or business.

I watched with great frustration as all of these 30amp stations have popped up around California. I've repeatedly suggestions to business owners that they are making a mistake by choosing this technology when for about the same price they can install an 80amp station. I predict that within a few years most electric cars sold will support higher amp charging and charge station owners will be frustrated by requests to replace the 30amp stations they only recently installed.

I hope we can convince companies like Chargepoint and Blink to start offering an 80amp option, convince government to include these in their tax incentives, convince businesses to invest in higher amp stations, and convince car manufacturers to include or offer higher amp options on their cars. This, coupled with strategically placed fast charging, will make driving electric cars long distances both practical and relatively convenient to virtually any destination.

· · 4 years ago

BTW, maybe your exclusion of Tesla was based on the "J1772 compliant" criteria you mentioned. While the Model S' native port is proprietary, every Model S comes with an extremely simple, small snap in adapter that allows use of J1772 stations with virtually no extra effort. So I don't think this is a meaningful distinction for a car with a very large market share among EVs.

· · 4 years ago

Great post Nikki. Totally agree that 20-25kWh charging as being an economical sweet spot relative to charge time. A major hurtle are infrastructure costs for 480V power; particularly 3-phase which is mostly constrained to industrial parks in US. 3-phase power in Europe & Asia tends to be more accessible.

19 kWh charger stations are already reasonably priced (~$2000 range for 240V - 100 Amp) J1772 AC. e.g.
The limitation, (as Nikki notes) is most EV models manufactured today don't have on-board charging above 3.3, or 6.6 kW/h. Charge rate is limited to the 'smaller' of vehicle & charge station values.

To organizations installing J1772 AC charge stations, they should consider 19 kW/h stations so their infrastructure will not soon become outdated. Today, Tesla Model S and Roadster can use the 19 kWh with a Tesla J1772 adapter (to connect Tesla's unique plugs).

Just think, most EV models (LEAF, Volt, iMiEV, Fit, Smart-ED, 500e, Spark, etc) with 16-24kWh battery pack would be able to charge in ~one hour, or less!

· · 4 years ago

Sorry Nikki, more misinformation in your article.

The Tesla S has a $1500 option that will allow 80 amp (ideally, 19.2 kw) charging, and this from the standard j1772 adapter included with purchase of the car. Far from "No cars on the market support this charging rate", Tesla informs me about 30% of all model S deliveries have been the 80 amp models. And my roadster has done 16.8 kw for years.

Also, the base Nissan model still has the 3.3 kw charger standard.

Traveling salesmen and other high mileage drivers need an 80 amp charger. I'm unconvinced about the rest of us. 30 amps is more than enough for me, simply because I don't travel extremely far EVERY SINGLE DAY.

However a larger battery would help me, and I would not need to increase the size of my charger since it is not necessary to fully recharge a big battery immediately. For my purposes, actually 10 or 15 amps would be adequate for me. I purchased a 30 ampere unit a few years ago since I was uncertain of my driving patterns, I use it to charge 2 separte EV's, the EVSE was cheap enough, and 30 amps for one household is not that big of a deal.

I would never criticize someone who bought a 16 amp charger with a huge battery. For some people its an excellent combination.

· · 4 years ago

Agree that faster L2 would be a good option. MINI E charged at 12 kW on J1772 converted Tesla sites adding ~50 miles of range per charge hour. AC Propulsion “Reductive” and Renault “Chameleon” on-board chargers repurpose the inverter’s high power components to manage price and weight. But, I understood there to be a patent (ACP), or grounding (Chameleon) reason that other manufacturers cannot do this in the US?

· · 4 years ago

I found most of what Nikki's been posting in the past (incl. at GCR) relevant and informative, but I completely disagree with her position here. It looks amazingly out of touch.

I've been driving a Leaf for over a year, and the combination of slow L2 charging (overnight) and fast L3 (on-the-go) it offers is IMHO ideal.
I don't see a need for something in-between, it offers no benefit I can think of and only adds to the variety of charging options already confusing to people new to EVs.

As the article points out, regular L2 is plenty fast for charging overnight or at work: even at 3.3kW, a completely empty 20~30kW*h pack will be fully charged by the time it's needed again.

For charging en-route however, anything less than the fastest possible rate (50 kW for the Leaf or i) is painfully and needlessly slow.
Would our traveling salesman prefer 1h on (non-existent?) 19kW L2 or 20-some minutes on already-deployed L3?
Next, imagine doubling that because the charger was in use and (s)he needed to wait for his/her turn. Or tripling that because this L2 turned out to be a regular EVSE maxing out at 30A -- oops. Occasional bad experiences like this will surely detract some from considering an EV.

Nissan, Mitsubishi and Tesla got this right: quick-charging needs to be unambiguously quick, boosting range in minutes not hours.
We need more such stations, not yet-another, lesser alternative.

Another point they got right: the bulky electronics to make this happen are best left at the curb. It helps keep the vehicles simpler, lighter, cheaper; charger costs are spread over many users.

Speaking of which, re 80A L2 vs L3 installation: commercial buildings typically get 3-phase standard already, no issue there. Next, pulling 3 conductors instead of 4?.. Negligible savings. Or did I miss something?

· · 4 years ago

@Mr O

You're right.. Anything can be converted into anything. The only questions are at what cost and who pays for it. But here we disagree, the costs are *NOT* negligible.

I'm frankly quite surprised at the amount of misinformation in general.

In other news, Detroit Electric has teamed up with another Chinese Automaker. I wonder why no one is snapping up Fisker? Maybe the Chinese are shrewdly waiting for the right price entry point.

· · 4 years ago

I think the only thing to bring the nonbelievers into the EV fold is to get back on the road with a robust economy. Fuel prices will go up then and EV's won't be a scary new technology anymore.

The risk takers have already made their moves but there's too much perceived risk for most people. Let the current owners of EV's iron out the bugs and when the sky stops falling the EV will be a more mature product with unmatched low running costs compared to anything relying solely on the internal combustion engine. Manufacturers will get their mix of features spot on, batteries will improve and the tipping point will be reached.

Charging speed or infrastructure is the excuse a lot of people use but in my opinion it's really conservatism which is understandable. Times are a little shaky.

· · 4 years ago

Thanks for the comments. As those of you point out with Teslas, it is possible to do faster charging with some Type 2 stations. But for cars other than Teslas, there's still a massive difference in charging capabilities from Level 2 units.

As for Chademo? It's still too expensive to be widely used. :(

· · 4 years ago

Again, I agree with you Nikki. Just note that Teslas have a pretty huge market share of recent EV sales.

Re others' comments, Chademo and super charging are great, but they aren't practical for every location. On the other hand, anywhere that can put in a 30amp 240v station can probably put in an 80amp station instead. Much better to charge at >2x the speed at those locations for similar installation cost and let people get to more places while we wait for the future fast charging infrastructure.

· · 4 years ago

@Bill: Not sure where you got that impression, but, no, I certainly don't think that a converter between AC and DC charging protocols would be cheap, nor practical. That's why it's IMHO important that whatever gets installed is in line with what people are likely to use.
Right now it's a mix of regular L2 (30A J1772) and L3/DCQC (CHAdeMO + Tesla S).

Re cost, I was only commenting on how Nikki's suggested high-current L2 compare to L3/CHAdeMO.
And again, in my opinion, super-L2 is not just needlessly slower and more confusing, it's simply not cost-effective as a replacement.

Engineering/permitting, trenching, masonry if needed etc will probably represent the majority of the expense, and are common to both installations. Where the differences are:

* CHAdeMO: chargers start at 15k$ (Nissan announced one for 10k$ but it hasn't materialized yet). Most require 3-phase service, which is what commercial buildings typically receive.

* 70~80A L2: dumb EVSEs start at 2k$. Single-phase => 3 conductors instead of 4 of comparable ampacity, really not much saving there. But because even that beefier-L2 remains 2~3x slower than L3/DCQC, that many more would need to be installed to serve the same number of cars.
Furthermore, we now have to add 1500$ minimum to _each vehicle_ for the oversized onboard charger -- certainly not something which will speed up EV adoption if you ask me.

Unless we plan on having one such L2 for every couple cars, CHAdeMO comes out cheaper overall.

· · 4 years ago

Mr. O hit the nail on the head - the elephant in the room is the cost of adding an 80A charger to each vehicle (L2). The alternative is placing a single 50-120kW charger on the ground that all cars can share (DCQC). Tesla seems to have figured this out because they use the SAME 10kW charger as they use in their cars, stacked up 9-12x, to make their supercharger. How's that for economies of scale?

In a (hopefully not-too-distant) future where EVs are common and the charging infrastructure is ubiquitous, I would think the DCQC model would win hands-down because multiple cars share the same chargers, rather than carry around their own.

· · 4 years ago

Initially, I thought this article made sense: for not a lot more cost, if EV makers put 20kw capable chargers in their cars we could already be getting "pretty" fast charging on the road for less than the huge costs of Level 3 QC stations. But, as I've read the comments, I agree that we'd be better off trying to get Level 3 going than just improving Level 2. In part because of the already existing EVs that will NEVER be able to use faster level 2 (including my iMiev) but also because if you're on the road, or at a rest stop on a turnpike/freeway, an hour to charge up is too slow. I've been on some longer trips (100 miles) that were out of my car's range and had to stop at a level 2 (for an hour or two in each case) ... if there had been a QC, my stop might have been only 15 minutes and I could have then made it home and charged overnight. That would have made my trips only slightly more inconvenient than an ICE - only CHAdeMO could do that for my current EV.

· · 4 years ago

Apparently our favorite restaurant owner TOM is the only one here who has paid a demand charge because he is the only one (besides me), that is saying there is no business plan for level 3 chargers.

I don't know why Nikki is saying CHAdeMO is so expensive since 90% of the Leaf's sold have this in my area, even though they couldn't possibly be used simply because to date, there isn't a SINGLE L3 charger around here.

Re: 30 amps vs 80 amps this is true for single family homes only. And if electric cars ever get really popular where EVERYONE has one, then there will be demand limitatons on residential services as there were decades ago. For apartments, or fleet areas where they have to pay demands, the proper size charger is one that runs exactly the length of time of the time of day discount to fully charge the car. This minimizes the demand charge. For a nissan Leaf thats about 14 amps.

Manufacturers and their customers, disagree with most of the posters here, since 30 amps is the most popular size, and most manufac\\tures dont even offer anything bigger. Many offer much smaller.

Most volt owners drive alot of miles on just 120 volts.

· · 4 years ago

Faster L2 charging would make EVs much more attractive to me. Being in Missouri, I don't expect to see any L3 chargers around here until... oh... the year 3000 or so.

· · 4 years ago

@Bill: "there is no business plan for level 3 chargers"

I disagree. There is a business plan for level 3 chargers - as a tool to sell more EVs. This is exactly what Nissan and Tesla are doing. For those not in the business of selling EVs, there probably is no profitable plan, at least for now.

· · 4 years ago

@Brian Schwerdt

Thats's true, but then you are closer to Ottawa Ontario than I am. You could conceivebly drive to someplace from your house, but no so from mine.

· · 4 years ago


Business owners probably chose 30 over 80 simply because most cars don't do over 30 yet, there's gov't grants for the 30 amp model capital cost, and more importantly, they don't want to kick up their demand charges.

a 30 amp 208 volt charger will kick up the demand 6.3 kw if a car charges during the late day, early evening.

a 80 amp 208 volt charger will kick up the demand 16.6 kw.

So if you're a business owner with SCE as your utility, you can either pay an extra $126 per month fine PLUS the electricity used, or $332 per month, plus..

Of course if you are thinking about putting in an army of these things at one location, there must be a gov't grant involved, so then yes, since money is of no object, put in 20 level 2's and 10 level 3's and get the utility to put in a 750 kva pad transformer and bill the feds for everything. Or get a several million dollar grant for a windmill farm or solar farm.

But, back to the real world, another issue is that if its a relatively small business location, the utility might complain about the load imbalance. Mine certainly would. Most businesses taking 3 phase dont have enough single phase lighting loads to rejigger than overall load profile. 30 amps is doable, 80 is not.

· · 4 years ago

There are a lot of people here with a lot more technical knowledge than me, and also who have driven EVs a lot longer, so my comments are subject to change later on as I learn more. However, I'd definitely appreciate an enhanced Level II charging experience. As a driver of a 2012 I MiEV, it would be much nicer to plug in somewhere for an hour and get 20 miles than to get 10 miles. While not "ideal" it could make the difference between making a trip worthwhile and just not bothering. I am getting 75 miles on my battery right now. But that takes 22 hrs at home on 120 and 7 hrs at a Level 2 unit...pretty much takes away any sort of middle distance trip. But going 40 miles, charging for an hour or so and getting 20 miles back would work wonders for many of my trips. Lou

· · 4 years ago


I hear that..... The problem around western ny is that we don't have much of anything, other than a few 200 volt 30 amp units, mostly at Nissan Dealerships. It would be handy if there was ANYTHING between big cities. As you, sometimes my battery just isn't quite big enough and I only need a 10% charge to have confidence to complete the trip.

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