Quick notes about Android Automotive Operating System, AAOS. I like it quite a bit. It’s part of why I bought the Volvo C40 Recharge.
AAOS is an Android-based operating system for cars. As the owner of a car, what I see is that I now own another Android device in addition to my phone and tablet. It has a different UI but it works like Android. I can install custom apps on it. And the default apps are quite good. Google Maps, of course, but a special version with EV charging info built in. Even better it integrates with my car’s systems so Google Maps can, say, look at my battery charge and help me plan a route. It also has Android apps for controlling the air conditioning, etc. AAOS mostly is visible on the car’s central display but it also integrates deeper into the car systems and the dashboard display.
Car software generally sucks. AAOS doesn’t, it mostly seems good and modern and not some OEM nightmare.
AAOS is different from Android Auto. Android Auto lets you mirror your Android phone’s display onto a car screen. Apple’s CarPlay is the equivalent thing for iOS. My C40 supports CarPlay but not Android Auto. I think they decided that Bluetooth integration with an Android device, plus maybe a little OS support to bridge things from the phone, was enough. I’m happy that calls, text messages, and media playing still work fine from my phone. But mostly I just run Google Maps and Spotify on the car itself.
GM/Chevy recently made the news that they were dropping support for both CarPlay and Android Auto in new cars. They’re adopting AAOS instead. That’s weird; AAOS can support the display mirroring mode. Dropping CarPlay seems like a real mistake, folks in Apple’s ecosystem are going to miss it. Also the press release suggests they’re doing this because they want subscription revenue; they can’t charge you if you’re just using your mobile phone to control the car. That sucks.
There are fewer AAOS apps that Android Auto apps. And both systems require extra work to support by app developers, a separate UI and affordances to not distract the driver. Here’s some developer info about AAOS apps from Google.
In practice I find the apps I want for my car are on AAOS. PocketCasts, Spotify, PlugShare. It even has YouTube and a web browser (only usable when the car is parked). Strangely A Better Route Planner is not on my C40. They do have an AAOS version for Polestar, not sure what’s going on there.
I was confused about what I’d need for a charger at home for my EV. It’s far simpler than I realized. Lots of notes here specific to North America. Simple summary: get an electrician to install a new 50 amp circuit with an NEMA 14-50 outlet on it. Then use your car’s provided charger or buy a high quality charger like a Chargepoint Flex or an Emporia for about $500. You’re done.
Here’s lots of detail I’ve learned in the last week or two. Shoutout to Reddit /r/evcharging and in particular this wiki page and this post. They have useful if opinionated info.
How AC charging a car works
I’m only talking about Level 1 & 2 charging you do with AC power from a wall outlet. I’m ignoring Level 3 charging: that’s high power DC stuff you’re not doing at home. With AC charging everything from the wall outlet to your car plug is just to supply AC power to your car. It’s mostly just a wire; all the fancy stuff is happening in the car itself. The thing we call “a charger” on the wall with the plug is doing so little that “charger” is not really the right word. The Reddit nerds prefer the term “Electric Vehicle Supply Equipment” (EVSE).
Most EVs today use a J1772 plug that is carrying +120V, -120V, and ground to your car. It’s mostly a fancy extension cord. There are also two signal wires: one is used to detect that the cable is plugged in, the other is a simple protocol that tells the car how many amps max it can draw from the charger. Providing those signals is the only extra necessary thing an EVSE is doing.
Tesla has a different plug, the NACS plug. And starting in 2025 all North American EVs will use this plug instead. I don’t know details but NACS is enough like a J1772 that adapters are simple and cheap. During the NACS transition we’re going to be using a lot of those adapters.
Note that EVs have a charging curve: batteries charge slower and less efficiently the more full they are. Details are complicated and vary by charging source and car type. But all EVs charge better up to 80% or 90%; that’s part of why they all recommend not charging to 100%.
Level 1 and 2 charging
Level 1 charging is powered via a plain old plug, 110V AC and an ordinary NEMA 5-15 outlet providing 15A maximum (12A in practice). That gets you about 1.3kW and will take about 3 days to fully charge a typical EV with an 80 kWh battery. Everyone scoffs at how slow this is but can actually be useful if you’re charging in your garage and don’t drive much. Don’t write it off entirely!
Level 2 charging is also powered by a plug or can be hardwired. It’s higher power: 240V AC and often a 50A circuit. These high power circuits use a special plug. A NEMA 14-50 is common and typically will get you about 9kW, that 80kWh battery can be charged overnight. If you already have a 240V circuit in your house you can still use it even if it’s lower power or a NEMA 6-50 outlet. Level 2 is what people install in their homes.
Installing a power circuit
Unless you are lucky you probably need to install a new circuit in your house and that will require an electrician and maybe a permit. Go ahead and install a 50 (or 60) amp circuit, it won’t cost much more. And install a NEMA 15-50 outlet for the extra neutral wire. All this takes a few hours. I had no problem adding a 50A circuit to my 100A house power supply but houses with funky wiring, who knows.
The folks on /r/evcharging prefer hardwiring instead of a socket. It eliminates one point of failure, the need for an outlet, and possibly a GFCI breaker. On the other hand it means you need an electrician if you ever replace your charger, or at least do some tricky wiring. I chose the plug. Also there’s a question whether the common Leviton 14-50 outlets are up to the task of continuous high power draw for EV charging. I decided it’d be OK.
One weird thing is that for continuous loads, you’re only supposed to go to 80% of maximum rated power. See here or here for details. A 50A circuit should only actually have a 40A charger plugged into it. That 14-50 plug is also max 50A, so plug-in chargers stop at 40A. Hardwired will go to 48A because the plug is not a point of failure, although you will need a 60A circuit and breaker for that.
Choosing a charger (EVSE)
The EVSE does so little it seems unnecessary to spend a lot of money on one. Your car probably came with an adequate one and it may be all you need. The main distinguishing factor of particular EVSEs is a bunch of fancy scheduling and tracking software which are really not necessary. Your car probably can schedule charging itself. The tracking is not terribly interesting.
However: that charger is in your house. With a lot of power passing through it. This is not the place to cheap out on dodgy goods. Amazon is full of generic $200-$250 level 2 chargers that are not UL certified. They probably work fine but what if they set fire to your house? In the end I decided to pay more like $400-$600 for a trusted brand with UL certification. Almost all of them come with fancy software which you might then just ignore.
The evcharging wiki has a good set of recommended charger brands. I narrowed it down to three that had a plug version and were available on Amazon: Autel, ChargePoint, and Emporia. All UL certified, $400-$500 (on sale), well reviewed on /r/evcharging. I also liked the look of the Flo dumb charger but it’s hardwired only.
In the end I chose Emporia, mostly because it was the cheapest. And while I think the smart options are superfluous Emporia has an interesting suite of smart home electricity products. Including an energy monitor and a way to schedule the car to charge when your solar system has surplus power. I’m not using any of that now but I liked what the company is doing.
Conclusion
In the end it’s pretty simple to set up an EV charger at home. Running the circuit is the only hard part. You know what’s great? Never waiting in line at a gas station again. Having your car fill itself up every night when parked at your house.
Tesla runs a great charging network. Actually two charging networks: the Superchargers are the crown jewel with fast Level 3 charging but there’s also Destination Charging which is a network of power Level 2 chargers that are prevalent. You can use some of these in EVs with J-1772 + CCS plugs but it’s awkward right now. It’s getting better since the agreement on NACS and the transition is going on. In a few years we’ll all be using Tesla-style plugs (now called NACS or J3400).
Here is a map of Tesla chargers that can work with non-Tesla cars. It includes both “Superchargers open to Non-Teslas” and “Destination Charging”.
Access to Tesla chargers is via the Tesla app. Destination Chargers are often free, paid for by the business and/or Tesla. (Free is customary for a lot of J-1772 Level 2 chargers, too.) But now destination chargers can take money, too. I think Superchargers have always cost money although Tesla sometimes offers free charging as an incentive to Tesla buyers. For non-Tesla cars they cost about $0.50/kWh in California, or about what Electrify America is charging. Cars typically get 2.5-4.5 miles per kWh so this costs about about $0.15 a mile, or roughly the same as gas costs.
Level 2 / Destination Charging
The first trick is plug compatibility. You have to bring your own adapter for a J-1772 car, you are unlikely to find one to borrow at a Destination Charger. Amazon is full of “Tesla to J1772” adapters for about $80 that physically connect the two types of plug. I think these are relatively simple devices but there’s a locking mechanism and maybe a little signaling. These adapters will only work with LTesla’s Destination Chargers, not Superchargers.
The second trick is electrical compatibility. I think this just works. Level 2 charging is basically just providing AC current for the car to deal with, the car itself chooses the amperage and charging schedule. So it’s relatively easy. Most of the Tesla adapters I see promise 40 or 48 amps which is about the max level 2 you’re likely to see. A few specify 60 amps. In my car at least, I have to manually select how many amps to draw (Update: that may not be necessary).
The map shows several hundred Tesla Destination Chargers in California. Only one in Grass Valley.
I used one of these Tesla chargers for free in March 2023 in Florida. Worked fine and Hertz had provided an adapter with my rental Polestar 2.
(Interesting thing: J-1772 to Tesla adapters are half the price of Tesla to J-1772 and are much smaller. I think this reflects that in general the J-1772 connector is bulkier and more complicated. I wonder if that’s part of why the auto makers were willing to adapt the Tesla plug. Amazon has a few cheaper adapters but they look like scams with fake reviews.)
Level 3 / Supercharging
Plug compatibility for Level 3 charging is via Tesla’s new Magic Dock. If you tell the supercharger you’re not in a Tesla, it will unlock an adapter to J-1772+CCS that will work with your car. (The “magic” is that the adapter stays locked to the cable so you can’t take it away.) The Magic Dock is something of a temporary solution as NACS rolls out. Tesla is incentivized because it will get billions of dollars in federal subsidies for providing CCS compatible chargers. Good, that’s the subsidy working, assuming the Tesla Superchargers do function as promised. Musk sure is good at capturing government subsidies, it’s a feature of all his businesses.
I don’t know anything about electrical compatibility. I believe Level 3 requires significant negotiation of charging power. Presumably the Tesla charger speaks whatever software protocol CCS uses. I wonder what the endgame is after NACS is fully rolled out; will there be one protocol standard or two?
The map shows exactly two Superchargers for non-Teslas in California: one in Placerville and one in Scotts Valley. Both are charging about $0.50/kWh.
Commentary
Tesla has done a fantastic job building out a fast charging network. There are Superchargers in lots of places, they work well, and often they are pleasant places. They have a mature product with memberships, incentives, and mechanisms for third party billing (like a car rental). And their plug and cables are lighter and easier to use than J-1772 + CCS. I’m glad they won the standards war.
I hope we get a robust market of competing Level 3 NACS chargers. It will make a huge difference in Americans’ willingness to switch to an EV. I keep hoping someone figures out a business model where the charger is a destination. It might take 30 minutes to fill up but if you know you can get a good coffee or some decent tacos and the WiFi works, that’s not so bad.
Volkswagen sure shit the bed with Electrify America. That could have been a real competitor to Tesla’s Supercharger, making lemonade from their emissions fraud lemons. But instead of embracing the opportunity they did a bad job building a charging network. There’s lots of chargers, sure, but they are always broken. Also the Walmart parking lots they tend to be in are not exactly lovely. And their website and app are badly implemented. In general it’s just a poorly executed product. Opportunity missed.
The web is full of spam when you look for info on Tesla and charging. Zillions of websites with wordy low quality content farm articles, presumably partly AI written.
I’m about to get an electric car so I’m looking again at what I pay for electricity. Up to 54¢ a kWh! We have some of the highest electricity prices in the world. Also some of the most unreliable power for a supposedly advanced nation. And occasionally PG&E’s negligence kills some people or a whole town.
I have two houses and a full panoply of rates I’m paying. It’s remarkably hard to find the actual rates on the website or in your bill but this PDF has an overview of the common residential plans. Also the rates are hard to understand. There’s two tiers: a “baseline” and then overage. I’m only looking at overage prices. Also prices may vary based on time of day or season of the year. In total I use about 7000 kWh a year in San Francisco and 17,000 kWh a year in Grass Valley. There’s solar in GV that gets me to about net zero for that house on a yearly basis.
I’m mostly interested now in what it will cost extra to charge my car. I’ll only charge at night. I’ll be paying fully the higher tier pricing for the incremental extra electricity. I’m guessing I’ll use about 3000 kWh a year (or 13% more) for the car. Because of how the NEM 2.0 rate plan works there’s no advantage to me charging directly from my solar: PG&E credits me fully for everything I give them.
In San Francisco I’m on the old E-1 plan. There’s no time of day or seasonal adjustment. I’m paying 45¢ for past-baseline power. My car will be charging at 45¢/kWh.
In Grass Valley I’m on the E-TOU-C plan. (I also have solar under NEM 2.0, but that can be ignored here.) Power is more expensive from 4pm to 9pm, and for the four months of summer. Past baseline, prices are 46¢ to 54¢ in summer and 41¢ to 44¢ in winter. My car will be charging at an average of 43¢/kWh.
PG&E has a second time of use plan, E-TOU-D. It discards the baseline discount, has a shorter time window for peak pricing, and has lower average rates. My car there would charge at about 39¢/kWh. I think my overall bill would be higher though.
PG&E also has a EV2-A rate plan for electric vehicle owners. It’s significantly cheaper from midnight to 3pm (26¢) but then 43-57¢/kWh during late afternoon and evening. The car would charge at 26¢/kWh but the rest of my bill will go up. Too early to tell if it’s a net improvement for me.
Bottom line, if I charge the car 3000 kWh a year I’ll be paying about $1350 a year just to charge the car at my current rates. Which is just about what I pay in gas right now for the old car. If I switch to the EV2-A plan I might save $600 charging the car, but then the rest of the bill will go up and I’m not sure how much.
Update: in Jan 2024 the CPUC gave PG&E another eye-watering rate rise. Here’s an estimate of new rates (I think)
E-1: 53¢/kWh
E-TOU-C plan: 46¢/kWh
E-TOU-D: 35¢/kWh
EV2-A: ???
PG&E (or rather Opower) has a “find your best rate plan” that re-runs your old bills through each pricing plan and tells you what you would have paid in each plan. It’s not useful to me right now, but might be useful after owning the EV for a few months.
I had my first real experience with an EV these last two weeks, renting a Polestar 2 from Hertz to drive around the Ft. Lauderdale area. It was great! The Polestar 2 is a nice car, a comfortable sedan, more or less a Volvo S60. It’s a competitor to the Tesla Model 3 or maybe Model S. I miss the car and now wish I owned one! I used this as an opportunity to learn about how EVs work, these are my notes. I also posted about it as I was going on Mastodon.
Charging
The question “how do I charge this car?” almost stopped me from renting an EV. I’m glad it didn’t! It wasn’t as easy as filling up at a gas station but it wasn’t hard, and the free electricity + parking you get as a perq in some places kind of made up for it. There was a learning curve though, the variety of charger types is confusing. Hertz didn’t have much useful information for me.
The car has a 78kWh battery and about 220 miles of useful range. It uses 0.32kWh of electricity per mile. I was staying entirely in the urban area between Ft. Lauderdale and Palm Beach, so no experience of long distance trips far from chargers.
The first thing I learned about is the difference between slow, fast, and rapid chargers (or level 1, 2, 3). Slow / Level 1 is what you get with an ordinary AC socket, which in the US tops out at 1.5kW, so you’re getting 5 miles per hour of charging or 40 miles overnight. Not useful, I never did it. Fast / Level 2 is higher power AC, typically around 8kW. These are the ubiquitous chargers you see in parking garages, etc, and are often free. (See the green markers in the map above). It’s also what you’d have in your home. Fast charging is more useful; picking up 25 miles in range while having lunch for free is nice. But for a real fill-up you need a rapid charging station, a destination facility like a gas station. See the orange markers above. These have 50-150kW chargers and can fill a whole battery in under an hour.
Rapid chargers are what you need when far from home. There are not nearly enough of them, particularly between cities. And a typical location only has 3-6 chargers, each one occupied for up to an hour at a time by other cars. Also often several chargers are broken, none of these facilities are staffed and seem to be out of service for days at a time. Electrify America is one common brand, and expensive! But frequently found at Walmart locations. My favorite was an FPL Evolution charger in Wilton Manors, conveniently near a store and a good coffee place.
The other confusing factor is charger compatibility. There’s basically two options: Tesla and everyone else. In the US newer non-Teslas use the J-1772 connector at fast chargers and a J-1772/CCS combo at rapid chargers. Voltage and power are auto-negotiated. My Polestar had an adapter that let me charge with a Tesla fast charger and I think there’s some work towards making Tesla rapid / superchargers work with other cars, too.
EVs don’t want a full charge; it’s not good for the battery. Mine came pre-set to stop charging at 80%. The charging slows down towards the end too; that first 50% is very fast, up to 150kW (or more?) but it slows down to 50kW as it gets near the top.
Finding a charger proved pretty easy. I used the PlugShare app mostly. The Polestar maps app also has a database of chargers although it wasn’t quite as complete.
Paying for a charge was awkward. Many of the chargers want you to install their own proprietary app, even if the charge is free. I ended up with a small collection of apps and accounts, a hassle similar to paying for parking with an app. Electrify America had actual credit card readers, like a gas pump. That seemed great at first but one reader was broken and also then I didn’t have an app to easily check on my charging status as I went out shopping.
All in all charging wasn’t a big deal but it was definitely more planning and mental load than just putting gas in a car. A lot of this complexity was all about being in a rental car at hotels. If you own an EV you’ve probably made some arrangement to charge it at home, in which case most of the time you don’t need a public charger at all. For that matter one of the places I stayed had a free charger for guests; nice amenity!
Driving differences
The most fun thing for me was seeing how Polestar has re-considered the concept of car-as-product. Much like Tesla has.
It mostly drives like a normal car but not entirely. There’s no ignition! Just sit in the car and go. Gears are forward, reverse, and neutral. If you take your foot off the accelerator the car slows pretty aggressively, regenerative braking. This saves power and also means you can mostly drive with just the one pedal. Also the car doesn’t creep forward if you don’t have your foot on the accelerator. Both things too some getting used to but I ended up liking them quite a bit, they make sense for an electric motor. You can configure the car to simulate these gas engine legacies if you want.
A nice side effect is there’s no stigma of sitting in the car parked with the AC blasting cold air and the radio on. Just chilling in your portable living room. Sure, you’re using some battery, but that’s OK. There’s no gas engine idling, making noise and smell and waste.
The car controls and electronics are fully reimagined around a touch screen tablet and an Internet connection. No knobs for A/C, stereo, etc. The core software is Android Automotive. I found the UI very simple and straightforward with no unpleasant surprises. Maps works, car status apps work, all simple. I had a hard time figuring out how to turn the AC on. And finding the home button to get to the main UI. But those were both one-time things and once I learned them they were fine.
All in all it’s a nice car to drive. I was similarly impressed with a Tesla Model S when I test drove it. Reconsidering the car product and UX is a good thing.
Cost
I rented the car from Hertz at a nominal $53/day. That’s a pretty great price for a relatively high end car like a Polestar; I’d have expected to pay as much as $100/day for a gas car of that quality. Hertz seems to have made a major effort to promote EV rentals, they do a lot of Teslas too. I suspect they’re buying the cars at a discount, good marketing for Polestar.
Charging costs were anywhere from free to $0.30/kWh to $0.45/kWh. The car uses about 32 kWh per 100 miles, so it works out to $10-$14 per 100 miles if you’re paying for electricity. The similar Volvo S60 gets about 30 miles / gallon, so with $3.35 gas the combustion engine car costs about $11 per 100 miles. Bottom line, it costs about the same per mile in energy. Unless you skim electricity off of free chargers!
Hertz provided the car at 67% battery and told me to bring it back at 60% or more if I didn’t want to pay a battery recharging fee. I don’t remember what that fee was but it seemed about in-line with what you’d be charged if they had to add gas.
Summary
I really liked the Polestar 2. I miss it! I may end up buying one, or something similar. I’d gladly rent one again but if I were taking 100+ mile trips far from towns I’d consider the charging infrastructure available carefully. In a big US city, charging was only a minor hassle.
Nelson's log 