EV FAQ: how long does it take to charge?

One of the most common questions people ask about our Electric Vehicles is how long it takes to charge them. I’ve answered this in a variety of ways but I’m not sure I’ve ever fully answered the question. Part of the reason people are concerned with charge time is because one of the primary inconveniences of driving a car has been gassing it up. You must drive to a station, wait for a pump, insert a payment card, wait for authorization, select a fuel type/grade, start the pump, and then stand outside in the weather to monitor it. With a BEV, the vast majority of charging happens in your garage or driveway. Thus my answers tended to highlight this difference in “filling up” paradigms.

  • “About 30 seconds. I plug it in when I get home and unplug when I leave.”
  • “It depends on what I’m plugged into.”
  • “It doesn’t matter, because it charges while I’m sleeping.”

Those answers are valid, but they don’t tell the whole story. That’s because the story is complex. Let’s start with the simplified version.

  • Level 1 adds 5 Miles of range Per Hour of Charging
  • Level 2 adds 20 MPHC
  • DC fast charging adds over 100 MPHC.

EV Charging Levels

J1772 connector

Levels 1 and 2 use standard household (AC) current. The vehicle has an onboard charger that converts household AC current to the DC current which is stored in the battery pack. To charge at levels 1 and 2, a special adapter called an Electric Vehicle Supply Equipment (EVSE) is used. Every EV comes with an EVSE and they all share the common J1772 connector.

Then there is DC fast charging. Since the car doesn’t need to convert the DC current, it can charge the battery as fast the battery can store it. In fact, the car tells the DC charger what rate it can accept and then the charging station delivers as much as it can, without exceeding the cars limit. There are several DC fast charging standards including CHAdeMO (Nissan), Supercharger (Tesla), GB/T (China), and SAE Combo/CCS (everyone else).

Charge Times

Level 1, also known as trickle charging, is the slowest charge rate and uses standard 120V wall outlets that you can find nearly everywhere. On a typical 12-hour overnight charge, a BEV will gain about 60 miles of range. Considering that most people travel under 40 miles per day, L1 is often good enough. Older BEVs like our leased ’13 and ’16 Leafs included an EVSE that supported only Level 1 charging. We found it sufficient in all but the coldest week or two of the year.

Level 2 adds 20 MPHC. Level 2 is the most common and the EVSEs are rated by the maximum power they can deliver. The most common EVSE uses the 50A NEMA 14-50 plug, draws 32 amps continuous, and adds about 240 miles of range overnight. The NEMA 14-50 is the same outlet commonly used for electric ranges, ovens, generators, and RVs. You can often find the 14-50 plug in kitchens, garages, and campgrounds across America. The EVSE included with our ’19 Leaf and ’19 Tesla Model 3 both sport a NEMA 14-50 plug. If your garage doesn’t have one, getting a NEMA 14-50 outlet installed is a good bet. Be advised though, ask your electrician for an “oven outlet,” as many electricians have charged hundreds of dollars more for an EV outlet than the identical oven outlet.

If you already have a 240V outlet of any sort in your garage, there are 3rd party EVSEs with plugs matched to nearly any standard 240V outlet. A dryer, welder, air conditioner, or generator outlet in your garage is sufficient. Lower rated (~3.3kW) EVSEs can be found for $200-$300 whereas a reputable (ChargePoint, Clipper Creek, JuiceBox) 8kW EVSE will run about $500. If you have a Tesla, you can buy $35 adapters for the included EVSE for all the common 240V plug types.

DC Fast Chargers require more electricity than a house and are industrial machines. They are typically found at commercial buildings (like Nissan dealers) and along major highways. Whereas L1 and L2 stations are typically used at home, DCFCs are typically used on longer trips. Here’s a few examples of DC fast charging rates:

  • Our Tesla Model 3 Long Range can add 125 miles in 15 minutes, or 267 MPHC
  • The Chevy Bolt & Nissan Leaf can add 30 miles per 10 minutes, and 120 MPHC.

Careful readers may have noticed that the peak charge rate is substantially higher than the MPHC. That’s because Li-Ion batteries (just like in your phone/tablet/laptop) must be charged slower as they approach full. The tapering is much more pronounced with DCFC and it’s done to protect the battery. In fact, it is the car that tells the charger the rate at which it can accept power. Most EVs charge at their full rate up to about 80% and then taper. Because of tapering, long road trips in a BEV mean your trip will take less time if you charge to 80% and then leave for the next charging station. Tesla actually does this for you–it will charge enough to get to the next Supercharger (plus some margin) and then suggest hitting the road.

224035-8020-503.3 – 15
DC – CHAdeMO500125up to 140usually 50, up to 62.5
DC – CCS200-1000< 500dependsup to 350
DC – Tesla SuperCharger480300267140

Tesla has ruined me

Habits are funny things. We develop them after performing a repetitive task for about 2 months. Having formed the habit, we continue doing the same actions but we tend to forget that we used to need to think about the actions. Habits let us be unaware that we’re still performing them.

Having driven autos for nearly 3 decades, I had a collection of driving habits I no longer thought about. Driving my Tesla Model 3 for a while has let some of them fade away. This came into focus this weekend while driving 400 miles to Moses Lake and back for a math competition.

  • Braking. With a Battery EV (BEV), letting up on the accelerator initiates regenerative braking. The car uses the motor to slow the vehicle and store that kinetic energy in the battery. It doesn’t take long to become proficient at one pedal driving. About the only time braking is required is to bring our Tesla from a slow roll to a complete stop. While driving an older vehicle on this trip, I found myself thinking about braking: when to start, how much, why doesn’t this car have “brake hold,” and “oh yeah, I must press that brake pedal!”
  • Starting: For 100 years cars had ignitions. Starting a car is a series of steps:
    • Fish the keys out of wherever you stowed them
    • Insert the correct key into the ignition
    • Twist the key to start the engine
    • Release the key immediately after the engine starts
    • Depress the brake and/or clutch
    • Release the emergency brake
    • Shift into gear
    • Press the accelerator to drive away
    • Manual transmissions also require a synchronized release of the clutch and accelerator. Newer hybrids remove a step as they automatically start and stop the gas engine as needed. Some cars have smart keys that let you leave your key in your purse or pocket.
  • Until you try to teach someone else to drive, or get used to driving a BEV, it’s easy to forget how elaborate the startup ritual is. A Tesla has no start button. The steps in our Tesla are:
    • Step on the brake and shift into gear.
    • (if enabled): enter the PIN code.
    • Press the accelerator to drive away.
  • Stopping a typical car has a similar sequence:
    • Shift the car into park (or gear)
    • Turn off the ignition
    • Set the parking / emergency brake
    • Exit the car (and wait for everyone else to exit the car)
    • Lock the car
    • Store the keys
  • To stop driving a Tesla, you shift into park, get out, and walk away. If you’re at home and the battery is low, you might also pause to plug it in. A Tesla sets the emergency brake upon shifting into Park and releases it upon shifting into another gear. It automatically locks the car as you walk away.
  • My phone is my Tesla key and it can remain in my pocket. There is no ignition nor clutch. There’s not even a transmission: just a gearbox with a single gear. As a result of not needing to perform the typical sequences for a couple months, it’s entirely possible that over the course of 400 miles and 8 stops that at least once I:
    • tried opening the car door before unlocking the car.
    • got in, fastened my seatbelt, looked at the dash expectantly, unfastened my seatbelt, fished the keys out of my pocket, stuck the keys in the ignition, and refastened my seatbelt.
    • was reminded by the sound of the running engine to get back in and turn the car off.
    • started driving before releasing the emergency brake.
    • returned to the car to lock it, upon remembering that it won’t lock itself.

Please don’t use TurboTax or H&R Block

If you ever wondered why we can’t have single form tax returns, or automatically prepared tax returns with the information the IRS already has, the reason is because Intuit and H&R Block have made it illegal for the IRS to offer such a service.

They’re trying to perpetuate that status quo, permanently preventing the IRS from offering tax prep software. The best way to fight them is to never again pay them a single penny.

For tax prep, I’ve been using credit karma for the past couple years and I recommend it.

The Nissan Leaf is finally good enough

In 2012 we dipped our toes into the Electric Vehicle waters with a Ford Fusion hybrid. The Fusion uses the gas engine to charge the battery. The small battery can propel the car up to around 25 mph on level ground. Seeing how far I could drive in EV only mode become something of a sport and was the first step towards an all-electric vehicle.

In 2013 the Nissan Leaf was updated with a more efficient heater that got more range in cold weather. We calculated that it would be “just enough” battery to cover Jen’s 40 mile daily commute in mid-winter when headlights, defrosters, and heaters are needed in both directions. We stepped into the shallow end of the BEV market by signing a 3 year lease on a Leaf. The only issue we ran into was only having a Level 1 (120V) charger at home. During the coldest weeks of winter, charging is slower and plugging in when she arrived home wasn’t enough time to get a full charge by morning. After a week of very cold days, by Friday she wouldn’t have enough range and would take the Fusion instead. I got permission to install a Level 2 charge in our rented home, but never did.

In 2016 Nissan introduced the 107 mile battery. When our lease ended I handed our Nissan dealer the 2013 keys and leased a ’16 Leaf. That 30 miles of extra range let the Leaf do a bit more. We took it up to Steven’s Pass skiing, to Lummi Island for the weekend, and to Meany Lodge. We had to limit the highway speed to 60 and bring the charger so we could plug in upon arrival. When explaining the range limits to people, I found myself saying the ’13 Leaf battery was good enough 90% of the time. The ’16 battery was good enough 98% of the time.

Now my Nissan dealer has Leafs with 151 mile batteries. By the end of the month they’ll have the Leaf+ in stock with a 226 mile battery. Our lease ends in May. If we lease another Leaf, it will finally be good enough.

RIP: Methuselah

In the year 2013 we acquired our fish tank and a few goldfish from Highland Terrace Elementary. Months later our tank population grew when neighbor kids tired of their fish. The goldfish eventually outgrew our tank and retired to an outdoor pond. We replaced with a few Neon Tetras. One by one, the tank population shrank until 2016 when only one (from our neighbors) remained: Methuselah the Ancient.

Methuselah moved with us to our new home in 2016. After that initial year of construction and mayhem we added two more fish, three snails, and a pair of shrimp. Methuselah had tank mates again but he paid them as much attention as they paid him: not much at all. Methuselah the Ancient has been the subject of many stories and his old owners still come visit (he never knew they weren’t coming to see him).

On Saturday June 16, 2018, Methuselah the Ancient was found stuck to the intake of the water filter. Farewell oh ancient one.

while doing an oil change, I …

drained the oil, put the plug back in, and started pouring oil in the top. Then I noticed the oil filter sitting there waiting for installation. Oops. That’s the type of errors one can make after an EV becomes the primary vehicle and lots of time elapses between oil changes.

tankless water heaters

I just wrote this for a neighbor and am cross-posting it publicly here.

I’ve installed a couple of the EcoSmart models. When I installed them last year, Lowes stocked them. Today I see Lowe’s only stocks the Eemax (no experience) but now Home Depot stocks the EcoSmart. The only complexity on them is sizing: with traditional (gas or electric) the “standard” size is 40 gallons. For heat pump heaters, the “standard” is 50 gallons because they have a slower recovery time.

For tankless models, they are sized by flow rate and inlet water temperature. An example would be the 3.5GPM model. It would be sufficient to provide two simultaneous “fixtures” (think: shower + kitchen sink) with straight hot water (assuming low-flow fixtures) when the water comes out of the ground at 52° (summer/fall). In the winter when the ground and water is colder, it might not get the water all the way to 110° at flow rates higher than about 2GPM. That would be a bummer if you live with someone that wants to wash the dishes while you’re showering. So spend the extra $80 and get the 5GPM model.

The major usability difference between tank and tankless is that in practice, with a tank you get hot water for about 40 gallons + the recovery rate of the heater. That means about 50 gallons of hot water and then it starts getting progressively colder. In a family environment, that means: take your shower first. And install low-flow fixtures. With a tankless heater, the last shower is the same temperature as the first. It heats the inlet water up to your set point in real time, for as long as the hot water runs.

A tankless electric heater is about 15% more efficient than an electric tank heater because it has no standby losses. Also, if you tank is 3 miles from your fixtures, the tiny size of a tankless model means you can consider relocating the heater closer to the bathrooms(s) and/or kitchen where most of the water is used. That’s less pipe to warm up, less water down the drain, and less waiting for hot water. You can even go Euro with one small unit under the kitchen sink and another to service the bathrooms.

A downside is that you’ll likely need to install one (3.5GPM) or two (5GPM) additional 40A electrical circuits for a tankless model.

HomePod early impressions

After a few days with the HomePod I have a few impressions: setup is easy, using it is fun, it sounds great, and it works with our Family Music subscription. No surprises. At first, amusingly, a few people were tongue-tied while adjusting to “Hey Siri” instead of “Alexa.” That was entertaining. To watch. The biggest absence I’ve noticed from the HomePod is audiophile pretentiousness. I’ll explain.

I’m not an audio professional but I have mixed sound for bands. I’ve built a sound booth. I’ve recorded albums. I’ve spent hundreds of dollars each on used mics and monitors. I found that my limited musical talent was in listening. I enjoy carefully positioning my studio monitors and parking myself in the sweet spot. I can also count on my digits the hours in a year spent listening this way. That is my audiophile pretentiousness. To most everyone else, my monitors are just the speakers that sound good with movies. That system is normally switched off with a power strip because it draws 10 watts even when “off.”

In our home with two tweens, there are typically concurrent activities in progress and music is often emanating from the tiny speakers of a “smart” device someone is using. Even when playing back music I enjoy, hearing it from more than a few feet away on those crappy little speaker(s) is as much painful as it is enjoyable.

We also have a Sony RDP docking station / AirPlay speaker. It gets hauled to where someone(s) will be working (garage, basement, etc.) for a while. The sound quality is quite good when listening in front of it. Unfortunately, its power cords, adapter, and enclosure are too large and too directional to earn a spot in the prime real estate that our lives revolve around. It also requires a separate “smart” device to stream to it. As an auxiliary speaker it gets used many dozens of hours per year.

Last year we added an Echo to the kitchen and we’ve settled into a usage pattern. In the past month we averaged 5 requests per day (play song X, set a timer, set an alarm, what is an acute triangle?, etc.). Alexa is VERY good at alarms and timers. She’s less good at answering questions. Requests to Alexa about information are usually followed up by asking Siri the same question. Alexa is even less good at playing music. The speaker quality is terrible, if we’re far from the Echo or the volume is loud we have to shout at it, and it lacks access to our iTunes library and/or Apple Music subscription. Yet we’ve listened to hundreds of hours of music on Alexa. It’s used because voice control makes it easy, it listens to everyone, and it’s in the kitchen.

I purchased the HomePod to displace this frequent pattern of listening to music on a cacophony of lousy speakers (Echo, tablets, laptops). The HomePod cleared that low bar brilliantly. On arrival day my middle schooler walked in the door from school, listened, looked about, saw the HomePod, and issued a “Hey Siri” command. She squealed with delight, “Siri finally listens to me!” (Siri on our iPhones does not listen to the kids, to our delight). We are all pleased.

Saturday my brother-in-law visited and spent a handful of hours listening. We picked songs we knew and loved and walked around the kitchen and adjoining living room listening. We agree with most honest (non-click-bait generators) reviews: the sound quality and stage is excellent. We can both identify areas where the experience is slightly different than standing in the sweet spot of our favored color and distortion free speakers or studio monitors. That ignores Apple’s achievement: everywhere else in the room the HomePod sounds substantially better than any comparably priced speaker.

The HomePod is less for the audiophile “soothe the hole in my wallet” listening that requires sitting in the narrow sweet spot of a tuned and expensive stereo system with expensive speakers. HomePod is for the every day listening done while cooking dinner, sweeping the floor, rescuing Roomba from misadventures, and the myriad other activities we do while moving about the house. As WinterCharm said well, with HomePod “the room is the sweet spot.”

when uptime mattered

It’s been a while since keeping a single server online was A Really Important Thing. Instead of really expensive servers with redundant power supplies, fans, CPUs, and disks, we’ve moved on to networked file systems and arrays of much cheaper [usually virtual] servers. Still, on occasion I maintain some old servers and I still feel a tinge of regret when I reboot a system like this:

# w

5:18PM  up 584 days, 10:49, 1 user, load averages: 0.27, 0.59, 0.51

Net Zero mission accomplished

One of my major goals for our home renovations has been achieving Net Zero, meaning our house produces as much energy as it consumes. As one might expect, producing as much energy as we consume yields energy bills of less than $0.  Today I consulted my energy meter and extracted the following data points for calendar year 2017:

  • Energy Produced: 9,288 kWh
  • Energy Consumed: 12,396 kWh
  • Energy Consumed by Auto: 3,216 kWh
  • Energy Consumed by Building: 9,180 kWh

For the purposes of measuring building consumption, I subtracted the auto consumption (measured by our chargepoint home charger) from total consumption. Since our building produced 108 kWh more than it consumed, I can claim the Net Zero goal as accomplished.

Our home and EV together consumed 1,500 kWh less in 2017 than 2016. Looking forward, I anticipate a similar reduction in 2018 because we were using space heaters for part of the house in Jan-Apr of 2017. The heat pump for that area is now installed. Also, the concrete basement and downstairs walls aren’t insulated yet. I have the insulation (XPS & poly-iso) standing by and it will be installed before the next heating season.

I don’t expect an substantial efficiency improvements after 2018. All our energy systems are super efficient, our insulation levels are super, and our energy surpluses (say hello to Energy Plus) will be consumed by our current and future EVs. Any further efficiency improvements would have no economic justification.

Reference points

  • Average home energy consumption: 23,000 kWh
  • Average auto energy consumption: 15,000 kWh
  • A super-insulated (aka: ultra efficient) home typically needs 1/5 the energy for HVAC.
  • On average, EVs consume  1/3 the energy of an ICE vehicle.