December 29, 2023

Improving Electrify America and EV Charging

Last year my wife and I purchased our first electric car - a Hyundai Ioniq 5 - and we love it! Range anxiety is mostly not an issue and the included 120V charger is enough to keep our battery topped up for most of our daily driving. For longer trips we’ve been relying on the included two years of free 30 minute Electrify America sessions that come with each Ioniq 5. As the number of EVs on road continues to increase, however, the EA network is struggling to scale. During most of our trips to an EA station we’ve seen many broken charging stations and lines of cars waiting to charge.

ICE cars, gas stations, rest stops, etc have had over 100 years to get to where they are. Most drivers know how to fill up a car with the right type of fuel. Gas stations are designed to easily drive through so that cars can form a queue. Filling a tank of gas only takes about 5 minutes and pump can fill at the same rate from empty to full. This all changes with EVs.

How fast can my car charge?

Unlike a gas pump which can fill all cars at the same rate from empty to full, EVs have a more complex charging rate that’s based on a combination of the station, the car’s EV architecture, and the car’s charging curve.

Station speed and the car

Not all EVs can charge at the fastest rates. Most EVs can’t charge faster than 150 kW. Why does this matter? If there’s a line of cars waiting to charge, a mismatch between charging speeds can really slow things down. For example:

At a 150 kW charging station one 2022 Hyundai Kona would take 44 minutes to charge up to 80% because it can never charge faster than 77 kW. Even at a 350 kW “hyper fast” charger the car is still only charging at 77 kW.

EVCar’s max charging speed10 to 80% at 150 kW10 to 80% at 350 kW
Hyundai Kona77 kW44 min44 min
Hyundai Ioniq 5233 kW22 min17 min
Note: Filling a gas tank for a similar range would take about 2 minutes.

If a Kona were to arrive first and choose the “hyper fast” charger, they add 5 minutes charging time for the Ioniq while they still have to wait the same 44 minutes. Five minutes may not seem like much, but if there’s a queue of cars waiting this can really add up.

The charging curve

So far we’ve only charged to 80%, however. What happens if a car charges beyond that? All EVs slow the charging speed as the battery fills up to help protect the it. Charging the last 20% of a car’s battery can easily double the total charging time.

EVCar’s max charging speed10 to 100% at 150 kW10 to 100% at 350 kW
Hyundai Kona77 kW124 min124 min
Hyundai Ioniq 5233 kW50 min45 min

One Kona charging to 100% takes as long as 3 Ioniq 5s. If those Ioniqs are charging to only 80% 7 cars could’ve charged in the time it took the Kona to get to 100%.

These estimates are under ideal conditions and assuming all cars show up at the same time and don’t linger at the station after they finish charging. In less ideal conditions a single slow charging car on a fast charger can create serious backups.

This stuff is complicated and most EV owners don’t know about it (and they shouldn’t have to!). Names like “hyper” and “ultra” are meaningless, dealers don’t educate, and really the end-user shouldn’t have to be thinking about this math every time they charge.

How do we improve?

So what can we do in a world where every EV has a different max charging speed, every charging station has a different mix of rates, and some EV drivers may still need to charge to 100% to reach their destinations?

1. Let computers do the math

With EV charging rates changing every year, it’s not fair to ask consumers to know what charger is best for them. At the end of the day if someone sees a charger that says “350 kW” and another that says “150 kW” most people will choose the 350 kW option - even if their car can only charge at 77 kW.

The charging infrastructure, however, can easily know the max speed for each car and assign them to the best charger automatically. This would help avoid confusion for the customer and help keep charge times as low as possible for all cars.

2. Predict demand

Today’s EA app is very dumb. It shows you what’s currently available but isn’t able to forecast how busy a charging station will be. The app should have an idea of how busy a charger will by the number of views it has at any given time and could even include people who are navigating to the charger in the queue.

3. Use a queue

Most EV chargers today are first come, first served. This works ok for the first few cars, but once there’s a queue it can be confusing to determine who’s next. Additionally you never know when someone is going to charge to 100% and sit on a charger for over an hour.

The queue could be optimized for minimizing the total wait + charge time ensuring that chargers are assigned in an order that gets everyone through the queue as fast as possible.

4. Encourage charging to 80%

Rather than penalizing users for charging to 100% we can encourage them to charge to 80% to optimize charging times for all customers. Drivers who need the extra miles can still charge fully, but for those who don’t need to we can help them understand the extra time and cost of charging longer.

What could this look like?

When finding a charger the app could focus more on overall wait time rather than current availability.

When a driver checks in the app can show them the estimated time difference for charging to 100%. Additionally the app can highlight which chargers best match your car’s max charging speed.

If no chargers are available, the app can show the estimated wait time as well as your total time at the station.

Thanks for reading!

This blog post is meant more as a conversation starter rather than a complete solution. I’d love to hear what you think about a queuing system, charging to 80% instead of 100% and all the other charging challenges out there today.

Send me a note on Threads to let me know what you think!

I also owe a huge thank you to my amazing wife Zara Fishkin who’s a principal content designer at Slack and helped me think through and edit this post.


Why would Electrify America want to do this?

EA charges per kW delivered. They should want to maximize the number of cars they can charge in any given time period.

What about non-Electrify America chargers?

I mostly focused on Electrify America, but this all still applies to other chargers like EVgo and ChargePoint. Older Teslas also charge at different rates and superchargers from different generations have different max speeds.

What if someone wants to charge without using the app?

I totally agree. I selfishly ignored this in my thought experiment to keep things simple, but there are going to be plenty of drivers who want to charge without dealing with a number of apps. One idea would be to have charging stations provide a check-in kiosk for drivers without the app which could also show the queue and wait times like traditional gas stations show prices on large displays today.

What if I need to charge to 90%?

A driver can stop charging at any time. I’d originally started with a very flexible slider input so users could set any percentage as their target charge level, but decided to go back to 80% where speeds tend to start dropping and 100% which many drivers choose to charge to. These two options are enough to help estimate wait times and show the time / range trade-offs for a longer charging session.

August 5, 2017

Commitments in the age of bailing

A recent New York Times article from David Brooks visits contemporary bailing culture, where it's become easier than ever before to commit to something and then back out last minute. Before smart phones and the ever-present internet, canceling was so much more difficult and time consuming. I first noticed (and started participating in) the bail culture primarily through events scheduled via Facebook. The RSVP system made it so simple to reply yes to something that Yes basically became a sign of support rather than an actual RSVP. Friends were essentially saying "Sounds like fun!" rather than "I'll definitely be there". Maybe (now Interested) provided an even more explicit endorsement of bailing. One could have the appearance of support without the burden of committal. When hosting parties and events I quickly learned to only expect the Yes's and even then to be prepared for a few "so sorry, but I'm swamped with work" texts last minute.

While I'm definitely not a stranger to bailing, especially on Friday night commitments after a long week with the couch and Netflix beckoning me home, there's no denying that there is a cost to the false commitment culture. How many times can a person bail before inviting them starts become a second thought. What is the value of a friendship when it's not worth committing to?

To help combat these tendencies, Mr. Brooks recommends three simple bail barriers:

First, is it for a good reason (your kids unexpectedly need you, a new kidney became available for your transplant) or is it for a bad reason (you’re tired, you want to be alone)?

Second, did you bail well (sending an honest text, offering another date to get together) or did you bail selfishly (ghosting, talking about how busy your life is, as if you were the only person who matters)?

Third, did you really think about the impact on the other person? (I’ve learned it’s almost always a mistake to bail on somebody’s life event — wedding, birthday party, funeral — on the grounds that your absence won’t be noticed.)

I try to challenge my own bailing instinct and I love the idea of thinking through a specific lens. Why do I want to bail? How should I communicate it? And is it really something I shouldn't skip out on for the sake of the other party? I'll take this one step further and add an addendum to #3, how would feel if the other person were bailing on me. A little bit of empathy and sympathy can go a long way. So here's to making some commitments and actually showing up!

March 20, 2011

Guidelines with Room

Many of my classes this semester are focused on fostering productivity and creativity, whether it be in the workplace, as an entrepreneur, or in the design process. I’ve come across countless methods and theories, from the traditional brainstorming, to the philosophy of 20% creative time famously implemented at Google, and even simple iteration and ideation. One notion that has become particularly clear to me, especially when working in groups and teams, is that creative freedom is a must. Ideas should be allowed to be proposed and built upon, no matter what one’s initial reaction is. Allowing the first idea the opportunity to grow can create an ultimately different idea that provides the perfect solution.


This freedom, however, should not be extended forever, nor employed in all levels of the design or ideation process. The key is to implement creative freedom while eventually adding guidelines to ensure the ultimate focus is reached. A balance must be maintained between issuing constraining goals or guidelines at the projects inception and allowing creative possibilities to run wild. The greatest ideas come from thinking outside the box, but ultimately producing a product, presentation, or project comes from a conscience decision to follow a path to completion. Finding this balance is difficult, but it can be obtained by allowing for a brainstorming period in which all ideas are acceptable, and then slowly transitioning to a more practical path where the far flung ideas are set aside to focus on the interesting yet obtainable. Students, employees, and teams should not be given a strict set of instructions, but rather allowed to pursue a creative solution to the given problem, and then guided internally, or externally if need be, to produce the creative solution.

December 9, 2010

Advice for Studying Abroad

With only a few weeks left, I want to reflect on some of the things I’ve learned during the semester in Spain that might be helpful to others studying in Spain (and abroad in general) in the future. I think that studying in a foreign country is one of the best opportunities available to students as it allows them to see the world from a different perspective. Depending on the country one visits, his or her experience will be completely different and offer him or her a unique lens through which to view the culture and events of the world.


The two things I was most concerned about before coming to Spain were and what I would do about having a cell phone and what I should pack. Being in a foreign country with a bunch of people you’ve never meet before, your cellphone and Facebook become your best ways of staying in touch with people and making plans. In Spain, you’re not charged for incoming text messages or phone calls and if you have the same carrier as your friends, calls among you are free (except for the 15 cent connection fee they don’t tell you about!). Because of this, it’s best to sign up with all your friends so that you can talk for as long as you want (or at least for 10 minutes) without raking in charges. Spain, and most of Europe, use the GSM network, so if you’re on AT&T or T-Mobile you can use your own phone abroad as long as it is unlocked. For those of you on Verizon and Sprint, you’re out of luck unless you have a world phone like a Blackberry. You can buy a phone here, but it is definitely cheaper to just buy a SIM card to put into your own phone. I brought my phone to Spain and went with MásMovil where I was able to get a free SIM with the purchase of 15 minutes of talk time. MásMovil by far the cheapest solution in terms of calling and texting charges, and it also offers the ability to keep track of your charges through a well-designed online interface and lets you set up automatic recharging with a credit card. I know this sounds like an ad, but I was just really happy with the service I received. Before leaving, I recommend trying to find an old or used GSM phone from friends/family or online through Ebay to avoid having to buy one here. For those going to Spain, avoid HappyMóvil. Nearly all of my friends used it and had tons of issues like being charged for minutes that were never added to the account and poor customer service. Most of the cheaper prepaid carriers do not work outside of Spain, so if you’re planning on doing a lot of traveling you’ll want to look into their Europe coverage before making any sort of purchase.


Packing for a semester abroad is almost like packing for college. You have limited room in your suitcase and most likely in your room where you’ll be living, so pack sparingly and plan ahead. Two weeks worth of clothes should be plenty, especially if you’re living with a host family as they usually do laundry at least once a week. Planning around seasons can be difficult as the weather differs much throughout Europe. Spain is similar to the U.S. in that winter in the north lasts longer with more snowfall, while the south and coast are more temperate. In Madrid, the winter temperature stays around the freezing point while the Fall can be in the 50s-60s F and the summer can get into the 80s or higher. The best advice I can give is to pack for different situations and bring clothes that you’ll be able to layer so you can get the most of packing lightly.


There is more to packing than clothes, however, and this may be the most important thing to consider depending on where you go. You can get clothes anywhere, but medicines and toiletries differ from country to country. If you have a medicine that you take on a daily basis, bring enough for the entire duration if possible as it could be hard to get it while abroad. I haven’t bought contact lens solution in Spain, but we were told multiple times that it is different so I’d recommend bringing enough if you can. As far as school supplies go, Spaniards are not fans of college ruled notebooks, so if you are bring your own. Also bring your favorite writing instruments and don’t let your Dad take them out at the last minute to save weight in your suitcase! Definitely bring a computer, but if you have a 15” computer as I do you might want to consider a netbook or something a little smaller because it’s been pretty hard to travel with such a large computer.


Now for some general advice! Have fun and live with an open mind. The most important thing is to mesh with the culture while not losing sight of the fact that you’re only abroad for a limited time. This is something that I’ve struggled with a lot here (see the previous post) and is a difficult balance to find. There will be cultural differences, but don’t freak out. People are generally kind and forgiving (especially in Spain), so if you mess up don’t take it too hard and just learn from your first mistakes. Try new things, explore the culture and explore yourself! I realize that this post ended up being more advice on what to do about communicating and a little about packing, with barely anything about living, but there is really no advice to give for that except to enjoy it! There will be work and things might seem tough at times between the change in culture and missing home, but if you always keep in mind that you’re studying abroad surrounded by people and students from another country and another culture with a different view of the same world, it will be impossible not to find new and amazing discoveries each day.

October 15, 2010

Thoughts on Traveling

Every day I spend here in Spain I realize how many things I would love to see here but that I won’t have the time to. There are enough interesting museums alone to occupy me for years to come. One of the assignments for my sketching class involved a reading comparing travelers and tourists that argued that travelers embed themselves in the culture and society of their destination, while tourists simply visit the most well-worn paths of the travelers who have come before them. While I continue to suffer an ever-growing existential crisis, as every day that passes means one less day I will be able to spend in Spain, I feel like I am treading the line between the two.

An essential mode of thought for being part of the culture of a location is one of “I have plenty of time to see that”. As a kid growing up near Boston, it always amazed me that tourists would come to visit the city. Ya it was cool, but it was just Boston, the same as it had always been. The city was always there, a short drive over the bridge or a quick ride on the metro was all it took. Not until my high school years and ultimately college did I really begin to appreciate the nearly limitless activities offered by Boston alone. There are concerts and shows to see, parks to visit, and restaurants to try to name a few activities.

Living in Spain has really brought this dichotomy of the traveler and the inhabitant into focus for me. I find myself confronted daily with different opportunities, like going into Madrid to see a play, trying to get to a jazz concert at a small jazz café, or just making the walk to the weekly market by the facultad de documentación. I started this particular post in October when I still had two months left to take advantage of living in Spain. Now the semester is nearly finished and I have barely three weeks remaining in the country. What I started to realize nearly two months ago, that I was adapting to the mindset of the inhabitant, choosing to sleep in or stay inside instead of making the “trek” into Madrid, has only become more clear in the last few weeks. Time is always this arcane force that we’re constantly moving with while always fighting against. Whenever our particular time limit draws near, we tend to fight more and more until we are ultimately swept over the edge. With such little time remaining I can feel the precipice approaching faster than ever.

All this said, I’ve realized there is a balance that must be found between the feeling of being an inhabitant with all the time in the world and a traveler with limited time. One cannot do everything and it wouldn’t be an enjoyable experience to be running all the time trying to fit as much in as possible. At times the inhabitant must think like a traveler and the traveler like an inhabitant. My past weekend in Madrid is a perfect example of the balance I was able to find. On Friday night the end of the program seemed closer than ever and I had an existential crisis where I decided to live every moment in Spain to the max and take advantage of every opportunity I have here. Predictably this freak out made it difficult to fall asleep and I overslept, ultimately missing the train to get to jazz show I had planned on seeing Saturday morning in Madrid. Joder. I spent the day a little disappointed with myself and met with some friends in a café to do some homework. As the day wore on, however, I realized how much fun I was having just spending time with my friends here in a relaxing environment. Maybe this also counts as taking advantage of my opportunities? When would I be able to just sit in a café with hours, talking, hanging out and doing very little actual homework? That night we went out to an area in Alcalá, La Garena, that I had been meaning to make it to all semester but had never gone because it required taking the train or bus and getting a cab home. With tons of restaurants and bars in a small square it was a blast!

I slept in the next morning and took the train into Madrid at night to see a jazz show with some friends at a club near Sol in Madrid. The show was fantastic! The musician was American and as he improved on the piano he told us to leave all our worries behind and let ourselves be taken away by the music. Just what I needed to hear! It hit me that this was the perfect analogy for finding a balance in studying abroad. You have to adapt to the culture and ultimately forget your worries and let the culture take you away. I am living and studying in Spain, not vacationing or simply visiting. I chose the Tufts in Madrid program for this particular reason. Spanish culture is one of spending time in cafés and restaurants with friends, walking slowly down the street and sharing your experiences with others. Many times this includes going to museums or seeing a show, but other times it requires you to step back and slow down for a bit. As I near the last weeks of my time here, I’m trying to appreciate this relaxed perspective and keep a balance between my desire to fit everything in and the sanity that the Spanish culture helps provide.

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