EV Charging - the Long Form

More than everything you wanted to know about EV charging

EVs have big batteries, and the best EVs have the electrical system and battery chemistry and tech to store a huge amount of energy quickly. 

Home Charging Is Super-Convenient - EVs are fundamentally made to be plugged in at home whenever not driving. So, you wake up in the AM and they are charged, and that's using your cheap home electricity. (You can get by, but just barely, plugging into any regular wall socket or 110VAC. However, it's way better if you charge from a 220 VAC outlet, the same as an electric dryer, or stove plug. The 220VAC might take 6-8 hours for a big charge.)

"Destination" chargers are typically 220V chargers that need overnight for big charges; typically found at hotels. 

Fast-Charging - Along highways there are fast-chargers, like 250 kW Tesla superchargers, and 200-350 kW non-Tesla (public) chargers. 

Public vs. Tesla fast chargers: Tesla had the first big network of chargers in the US and several other countries. A 2023 report by JD Power of US chargers found that Tesla chargers were fast, convenient, reliable, and plentiful. Non-Tesla chargers ... not so much. Public chargers are often unreliable, and the fastest chargers don't have good highway coverage. BUT DON'T WRITE OFF PUBLIC CHARGERS: 

•7.5 *billion* dollars is on the way to fix public chargers through the 2022 Inflation Reduction Act, aiming making public chargers fast, plentiful and reliable; a Bloomberg report estimates substantial improvement by the end of this year. Until then, many non-Tesla users get along using the plugshare app, which tells you which public chargers ahead are available and working.

•Note well that the fastest chargers are NOT Tesla, maximum 350 kW to 250kW. Note also, however, this only makes a difference if your EV can accept that power, and then still only in the first few minutes of charging.

Non-Teslas can ALREADY use Tesla Superchargers - in June of 2024, we had already spotted a Mustang Mach-E at a Tesla Supercharger (pictured above).  This means that, given the right adapters, every EV can use every fast charger, everywhere. This is great news for people on the road, making road trips ever more convenient with lots of chargers to choose from. 

Charging Curve- A "charge curve" is a record of how much power a battery accepts vs. its state of charge, or state of charge vs. time, while charging, on a fast charger. As of 2024, all EV batteries charge fast at low charge, then get slower and slower as the battery gets full, though every car (battery + charging system) is different in detail.  One consequence is that to add 10 miles more range at a high charge, let's say 80%, takes MUCH longer than to add 10 miles at a low charge, e.g. 20%.  So, where possible, charging from a low state, just enough to get to your next charger, is very time-efficient.  See "Charger surfing".  

Temperature and conditioning - Batteries charge fastest when they are warm, and will be slower when it's really hot, or really cold.  See this link on Evs in the winter. So, if you want to use your EV in the winter, make sure it has a heat pump and battery conditioning.  Further, make sure you *tell* your car when you're going to charge, so it knows to condition the battery (on most EVs  you tell it by setting the next charger as the destination). How well a car conditions its battery is very important. The EV6 for example, apparently didn't have the software working to condition for more than a year after its introduction. (Yet another reason to be wary of committing to a car before the spec.s are published and the real production model reviews are in.) 

Battery Chemistry - Different battery chemistry is probably the largest factor in performance of batteries. With different chemistries, you can get different temperature sensitivity, energy (or range) per weight of battery, degradation with number of charges, degradation with fast charging, etc. etc. The two best known battery chemistries are NMC and LFP.

NMC stands for nickel, metal, cobalt, the cathode materials in this type of lithium ion battery.  These batteries have the best energy density of EVs on the market as of early 2024. 

LFP - Stands for  lithium, fluorine, and phosphate;  anyway it's cobalt-free, which means less questionable ethics in sourcing from the DRC. It has lower energy density than NMC, and as of early 2024, and performs significantly worse than NMC in cold temps. It's important advantage is that it is more robust to charging 0 to 100%, and potentially allows more charging cycles before degrading.  

Charger Surfing is the process of arriving at a charger near the safe minimum, e.g. 10-20%, then charging only until you have enough energy to make it to the next charger (with some reserve for temperature, wind, etc.), repeat ad infinitum. This can get you where you are going with much less time spent charging, compared to charging up to near 100%. This is because as of 2024, all EV batteries charge significantly faster at low state of charge, and significantly slower at high state of charge. This can be a very time-efficient way to road trip. See EV Long Drives.