Hacker News Reader

Comment by boringg | Hacker News Reader

Question for EV charging -- how does the economics work at a charging station? If I was an EV owner is it cheaper to charge at home -- and do I pay a premium at a station for fast charging? Are stations subsidized by say a Home Depot who just wants people to come to their business?

View on HN

1. It's cheaper to charge at home, and we do have a Level 2 charger in the garage. But with a new Hyundai EV, you get unlimited free charging (albeit, 30 minutes at a time) through Electrify America. There's one down the road from us at the local Target. So when one of us goes to Target, we get the "free" fill-up. In fact, just this morning I was driving by from some other errand, and figured, hey, I've got fifteen minutes so I'll throw the car on the EA charger and save a few bucks. But it only takes like five or six dollars to charge the thing at home, so did I save anything even if I didn't go out of my way?

Otherwise, L3 is for road trips, especially if it's coming out of my pocket. And partly because one of the reasons we bought our second electric car is because you don't have to go out of your way to a special place just to keep the thing running.

2. I've not seen free charging at places like HD. What I have seen are Level 2 chargers at Safeway grocery stores that are subsidized by the advertising on the giant-ass (a meter tall?) screen. Advertise all you want on that screen, I'm in the store not seeing it. Other places you'll swipe a credit card or summat.

Thanks for the response -- so it sounds like there are a lot of business models right now and a couple different options for the consumers.

That pretty much nails it, yeah. I expect we will see some shaking out of what works and what doesn't in the next five-ten years, but for now we get a hodgepodge of various schemes. OTOH, my wife and I been driving EV for over 12 years now (OG, pre-ordered Leaf), and though there are many more chargers, I don't know that the business models have made much progress.

It is cheaper to charge at home for sure, especially if we are talking about L3 vs. L1 or L2 charging. L3 charging (the one that gets done < 30 minutes) is more expensive to set up and power. It is meant for people on roadtrips, but a lot of people who live in apartments or use Tesla for ride shares also use them.

But if you have access to home charging and don't drive a lot, you'll rarely ever use a charging station. But when you need access, e.g. on a memorial day road trip, the L3 chargers you find will be swamped while the L2 chargers are too slow.

How frequent do you actually think chargers will be used? I understand that there are a lot of market dynamics but I would imagine that if we swapped to EV -- home charging/office charging would be the big ones with few people going to gas stations/convenience stores.

EV is partially sold as not having to go to convenience stores/gas stations to recharge.

Ya, probably. If most people are charging at home (or office) for most of their usage, chargers won't get used a lot except on holiday weekends when you travel a long way from home.

When you do charge, you'll be stuck at the charger area for ~20-30 minutes, so colocating them with restaurants and other things to do during that wait would be useful. You definitely can't structure them as drive through and out like a gas pump.

It is usually dramatically cheaper to charge at home at night.

For example, in Alameda California I pay:

* 15.17 cents per kWH during off-peak times (nights and weekends)

* 50 cents per kWH during peak times (5pm-9pm)

The Supercharger down the road charges:

* 51 cents per kWH from 12pm-11pm (the time you're most likely to use it)

* 41 cents per kWH from 11pm-4am

* 32 cents per kWH from 4am-12pm

No one is going to leave their car at a Supercharger overnight though. So more realistically you're paying over 3x the cost if you use public Superchargers.

My Model Y has a 75kWH battery so its about ~$11 to charge it from zero to full at home vs about ~$38 at a Supercharger during the day.

How do the economics work for the company running the chargers?

Great question! I don't know. I assume that Tesla pays the owner a flat monthly fee for spots but who knows. Likely some spots are more valuable than others. In some places Superchargers might bring in more people to the local businesses, but in others it might cost the owner limited parking spaces and hurt foot traffic.

38$ for the day is actually more significant than I thought.

Compare that to gasoline at ~$104 to fill a tank of gas on an Audi Q5 (rough equivalent of a Model Y. It has an 18.5G tank and premium gas is $5.65 here). The Q5 does get far more range though. Something like 450+ miles vs the 330 of the Model Y.

Maybe it is better to judge how many miles a dollar gets you? 8 miles per dollar for the Model Y vs 4.3 miles per dollar for the Q5.

If you charge at home during off-peak hours, like most people do, the numbers get a ton better.

A month or so ago I did a comparison between charging a Chevy Bolt at home, with just a level I charger, and putting gas in a Nissan Versa, Hyundai Elantra, or Kia Forte.

The Bolt will be cheaper per mile if G/E > 9.4, where G = price of gas in $/g, and E = price of electricity in $/kWh

I looked at average gas prices and residential electrical rates in all 50 US stats plus DC, and in all of them G/E > 9.4.

This comment has a table showing G and E for all states and DC at the time [1].

[1] https://news.ycombinator.com/item?id=36978950

Reply on news.ycombinator.com