Thursday, September 19, 2013

Which Electric Cars Charge The Fastest?

When you ask a simple question, you normally expect a simple answer, right?


The problem with asking “which EVs charge the fastest” is while some may think it’s a simple inquiry, it really isn’t. In fact, if we had to put asterisks on the highly qualified answers for the 10 electric cars sold in America, we’d need asterisks for the asterisks.


But for those of you who grew up accustomed to quicker gratification – from such experiences as drive-in restaurants, and, well, quick-filling gas stations for example – the list is under “Recharge Times” below.


If you want an easy answer, go ahead and skip over the following qualifier sections if you dare.


Asterisks And More Asterisks


Are you still here? Cool. We’ll try to keep this simple and more interesting than the fine print for a credit card app, or what have you.


Rule number one is, assuming an “empty” battery, EV charge times depend on the kilowatt-hours (kwh) of the battery being charged, and how fast it will accept juice.


For example, the Mitsubishi i-MiEV has the smallest (16-kwh) battery and the Tesla Model S comes with the largest 60-kwh or 85-kwh battery.


All conditions being equal, a larger battery takes more energy, and this should mean a longer recharge time.


Mitsu-i-MiEV_Arch


But we warned you answers need qualification. Believe it or not, in this case Tesla has figured a way for people at home to cram electricity back into its 4-5 times larger packs much faster than the i-MiEV, but we’ll explain this later.


Another factor to be mindful of is the electric current delivered by the charger. Actually, the “charger” is not the device with a cord you plug into the car. The “charger” is the on-board charger built into the car – often 3.3 kw, or 6.6, kw, and in the case of Tesla, 10 kw or a pair equaling 20 kw.


The rate at which the car’s on-board charger passes juice to the battery pack makes for an effective bottleneck. As a loose analogy, with a garden hose you can’t very easily water your lawn faster than the hose will allow, can you? So it is with the charger. It delivers electricity at a certain maximum rate, and that’s it.



Nissan Leaf with aftermarket charger installed.



(Of course if one were to retrofit a faster on-board charger, aside from voiding the warranty and possibly causing other problems, he or she might charge the car quicker, but we’ll leave this discussion at that).


And if these aren’t enough qualifiers for you, consider also the “EVSE” (Electric Vehicle Supply Equipment). Often mislabeled the “charger,” these matter as do also the amount of volts and amps of the circuit it is plugged into.


To sort of level the playing field, our list below focuses on official manufacturer ratings for 240 volt – AKA “level 2″ or “220” volt – power fed through a “charger” (actually the blandly titled EVSE.)


EVSE


A 240-volt EVSE is something most EV owners choose to install. If you want to plug into 120-volt “house” current with the included cord, plan on it taking around a day and a night or longer to recharge a depleted battery.


EVSE units are basically a fancy switch with safety built in to prevent unfortunate things like you electrocuting yourself, or taking or delivering more power than would be copacetic.


They plug with a special multi-pin connector into the car – usually an SAE J1772, but Tesla (like Apple) which likes to “zig” when everyone else “zags” – has gone its own route with a proprietary plug and port, but offers adapters.


bosche_evse


The EVSEs sold today vary in their maximum amperage and kilowatt output and thus can serve as another effective bottleneck.


Manufacturers typically quote level 2 recharge times based on the assumption that you are using the most potent 240-volt EVSE possible, often 30 amps with kilowatts varying.


If an EV can take more amps or kilowatts, that means they can replenish more “miles of range per hour” as Tesla puts it.


These details are not always spelled out in graphic detail by EV sellers, but the good news is it is not advanced astrophysics. When we asked every EV maker in America today to answer the same list of questions, we got varying degrees of transparency. Some did not know all the answers, some failed to even get back to us, and Fiat (Chrysler) took the cake as being the most crystal clear in its answers to the spirit of what we were asking.


“Amperes are everything when it comes to recharging. Charge time is directly proportional to amps,” replied Chrysler media rep Jiyan Cadiz. “A simple example would be, if you install the AeroVironment Level 2 EVSE (30 amp service) offered through Mopar on a 20 amp circuit, the charge time would be 1/3 slower (or 20 amps/30 amps = 2/3 max energy draw into the car).”


And we’ll add, if you buy a 15 or 25 amp EVSE and plug in a car set up for 30 amps or more, you have again effectively handicapped your recharge time.


On the other hand if your car can only accept 30 amps, and you plug in a 40-amp EVSE, software will limit the input, and it will charge no faster than at 30 amps.


We could go on and on adding qualifiers to this, but the simple answer is if you want fastest recharge times, the correct thing to do is to ask the automaker or a charging equipment supplier what’s the fastest way to go.


Among EVSEs, Tesla offers the most potent – its High Power Wall Connector (HPWC) – with up to 80 amps deliverable to cars with “twin chargers.”
high-power-wall-connector


This, by the way, is the answer to how Tesla at “level 2” can charge a Model S quicker than a Mitsubishi i-MiEV. The Tesla also costs around four times more, so go figure.


Tesla advertises that 62 miles range per hour gets added back to a Model S using its HPWC under ideal conditions of voltage, amperage and wire gauge size at minimal length. We know of one Model S Signature Performance owner who uses all 80 amps of his HPWC plugged into a dedicated 100-amp circuit, and gets only 54 miles per hour range.


Quicker Options


Beyond home charging, a few cars accept what’s called “level 3” or “DC Quick” charging. These expensive-to-install public EVSE deliver around 480 volts and a whole lot of amps. Tesla also has its public free “ superchargers.”


Final Note


NEMA_14-50_plug


If you plan to install a charger at home – for any brand EV – you will want to ensure the amperage of the line is up to the needs of the charging equipment, and ideally, use a “dedicated circuit.”


In other words, do not also run an air conditioner or clothes dryer on the same circuit, or this will limit the power to your car, and may even overload the circuit if it is not set up for this much draw.


EV Recharge Times


This list for U.S. market cars assumes the battery is fully drawn down to the point that its battery management system (BMS) has stopped the car.


All these EVs can be plugged into ordinary wall current, and some may be fine with that. Times list however are for the quickest level 2 recharge either estimated or as stated (often in ballpark terms) by the manufacturer.


For cars that specify a “preferred EVSE supplier” in most cases (except Tesla) it’s not required you go with only this supplier.


Honda Fit EV – under 3 hours


2013_Honda_Fit_EV1


Its smaller 20-kwh battery recharges quickly with a fast 6.6-kw on-board charger at 32 amps.


House current recharge time is estimated at 15 hours. Level 3 is not now available.


Leviton is the preferred charger manufacturer.


60-kwh Tesla Model S – 3.35 hours


Going with Tesla’s “62 miles of range per hour” quoted recharge rate with its HPWC, the 208 miles EPA-rated range of the 60-kwh car should be replenished in 3.35 hours. This assumes the twin on-board chargers rated at 20 kw.


Tesla_Model_S_Sunset


With only the single standard 10-kw onboard charger, or an EVSE rated at lower amps, times increase. Tesla quotes 31 miles of range per hour with level 2 and using its included Mobile Connector.


If Supercharger compatible, an 80-percent charge can take under 20 minutes. Preferred EVSE supplier for its proprietary charge port is, you guessed it, Tesla. For more details, check out Tesla’s Web page.


Ford Focus Electric – 3.6 hours


Ford-Focus-Electric-Feature-1213


The Ford Focus Electric’s 6.6-kw onboard charger and 30 amps makes for a rapid recharge.


Level 1 recharge time is estimated at 18 hours, and the car does not accept level 3.


Ford’s preferred EVSE supplier is AeroVironment.


Nissan Leaf – less than 4 hours


The 2013 models now have a 6.6-kw on-board charger either standard or optionally, and accept a maximum 30 amps.


IMG_9866


Previously the 3.6-kw charger was a bottleneck making recharge times for the 24-kwh battery closer to 7 hours. Preferred EVSE supplier is AeroVironment.


House current takes around 16 hours and a DC Quick Charge via a CHAdeMO port allows for 80-percent charge in an estimated 30 minutes or less.


Fiat 500E – less than 4 hours


Fiat_EV_FT013


Tied with Nissan’s time for level 2, the Fiat 500E also has a 24-kwh battery and 6.6-kw on-board charger.


Estimated charge time for level 1 is longer at 24 hours. Level 3 charging is not available.


AeroVironment is the preferred EVSE supplier.


85-kwh Tesla Model S – 4.27 hours


This one takes more asterisks than usual. Tesla likes to hedge answers, and indeed a lot of variables come into play.


The theoretically quickest time assuming Tesla’s “62 miles per hour” recharge rate with Tesla’s HPWC for its 265 miles EPA-rated range should be 4.27 hours with twin on-board chargers.


model-s-red-palosverde_1


If Tesla’s “300” miles range often quoted is indicated on its range readout – and as mentioned, depending on your real-world recharge rate – time could be longer.


“A Supercharger can charge about half the battery in 20 minutes,” says Tesla.


If equipped with only one 10-kw on-board charger, max amperage is cut in half to 40 amps, and charge times go up commensurately.


The Model S touch screen for fully equipped models allows charging input from 5 amps to 80 amps (in single amp increment/decrement settings) with all home or public charge options.


If you wish to use only house current, recharging at 5 amps could take up to 52 hours, 24 minutes.


For a fuller idea of variables, we suggest perusing Tesla’s interactive Web page.


RAV4 EV – 6 hours


Toyota’s Tesla-powered EV is actually estimated at “5-6” hours with its preferred EVSE supplier Leviton delivering 40 amps and 9.6 kw. The RAV4 EV also comes with a 12-amp Level 1 cable, but the maker “strongly” recommends the Leviton level 2 unit and does not even quote how long it takes at level 1.


2013-Toyota-Rav4-EV-Action


Note this unit delivers more power for the medium-large 42-kwh battery than other EVs can take and it still takes longer than most. If Tesla had outfitted it with Model S recharging technology, and even made it Supercharger compatible, that might have put this EV at the top of the list, but the omission is no surprise. Toyota estimates it will only produce 2,600 RAV4 EVs for California through the end of next year.


Smart ForTwo ED – 6 hours


Charging_Station_Stuttgart_2013


The Daimler-made Smart ForTwo ED comes with a smallish 17.6-kwh battery and takes around 6 hours with a lower-capacity on-board charger.


House current recharging is estimated at around 14 hours, and charging from 20 percent to 80-percent takes around 10 hours.


Bosche is the preferred EVSE supplier.


Mitsubishi i-MiEV – 7 hours


The i-MiEV’s 16-kwh battery takes around 7 hours to recharge at level 2.


i-MiEV


Mitsubishi is bold enough not only to offer the car in 50 states, it also confesses level 1 recharge time is 22.5 hours with the supplied cord.


The car also accepts DC quick charging via a CHAdeMO port that can replenish 80-percent charge in 30 minutes.


Chevrolet Spark EV – 7 hours


2014-Chevrolet-SparkEV-058-medium


GM only gave its 21-kwh battery a 3.3-kw onboard charger, so its level 2 EVSE from preferred supplier Bosche delivering 30 amps takes longer.


The upside is a SAE combo DC fast charger promises to charge the battery to 80 percent in just 20 minutes.


Relevance?


For those who want to travel the farthest in a day, quicker options can mean less “range anxiety.”


For example, a Nissan Leaf zapped back mid-day with a quick charger, may travel 150 miles or more, if the owner is resourceful, or fortunate enough to have charging options.



Range for any EV can also be extended with any sort of intra-day charging, so speed can make a differnce.


Obviously many other factors play into whether an EV is a good decision, and this is not intended as any sort of buying guide.


However, if you were curious now you have all the US-market EV charge times in one spot, but remember, “your actual results may vary!”

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