Paying for EV Charging

[charlie b]

I don't own an electric car, and likely won't any time soon. So I have no experience in this.

A government "housing project" is considering installing EV Charging stations (or at least the infrastructure for them) for use by building tenants. One person is resisting the idea because of the lack of a mechanism for payment. Let's ignore, for the moment, the complicating circumstance that the military base pays the serving utility for energy use and their contract probably doesn't allow the government to sell the energy to its users.

My first question: How much energy (in units of KWH) does it take to recharge an EV's battery from, let us say, a 10% charge to a 100% charge? I know that will vary widely with the type of vehicle. But can anyone give me a reasonable range?

My second question - for those of you who do own an EV: If you recharge you car at a place that charges you for the energy used, how much does it generally cost you?

 

[wwhitney]

1) EV battery sizes are anywhere from 20 kWh to 100 kWh, with a significant cluster around 60 kWh. I think you can assume 10% losses (maybe that's too pessimistic). So for a typical 60 kWh battery and your parameters, around 60 kWh.

However, with a dedicated charger per EV, one typically would not discharge down to 10% before recharging, that would be the exception and leaves a bit too little cushion for comfort. More typical would be 30%-70% (e.g. just plug in every night). I guess with shared charging you'd push the envelope more, but 30% still seems like a better example than 10%.

Another thing to bear in mind is that EVs vary less in their efficiency, they typically get 3-4 miles/kWh. 2-3 if it's a big vehicle and/or you're a leadfoot, and 4-6 if with a small vehicle and hypermiling (very efficient driving habits). So if you combine that with an estimate of miles driven per year, you can figure out the typical annual EV charging energy usage.

2) I don't know off the top of my head, but that information is publicly available. The various EV charging network should have it on their websites. Plugshare.com is a good directory of publicly available sites, so you can see what networks are near your location and what they are charging.

Cheers, Wayne

 

[hillbilly1]

Some have credit card readers, others have phone apps that turns the charger on, and billing thru the app. Some Corporate chargers have magnetic swipe cards to allow employees to charge. Technically, only utilities can charge for electricity, and some laws have/had to be changed to allow private companies to sell electricity.

 

[Hv&Lv]

Some have credit card readers, others have phone apps that turns the charger on, and billing thru the app. Some Corporate chargers have magnetic swipe cards to allow employees to charge. Technically, only utilities can charge for electricity, and some laws have/had to be changed to allow private companies to sell electricity.

But wouldn’t this be like an RV resort that is central metered yet has their own meter on each RV spot? You have to pay for how much electricity you use.
So a mall developer would install these EV chargers and recoup their investment, cost to charge, plus profit.

I don’t know, just asking...

 

[MD Automation]

Hi Charlie,

I just bought a 2021 Chevy Bolt about a month ago, so I can take a stab at question #1. I have yet to visit a commercial charger, so question #2 is unknown yet. Have only charged at work and home with the stock EVSE.

The Bolt has a 66KWh battery and an estimated range of 259 miles. The onboard charger maxes out at 7.7KW. So at a commercial Level2 charger (208 or 240 VAC), with the car using all it's 7.7 KW, I'd estimate 10->100% would be...

(66 * 0.9) / 7.7 = 7.7 hours

The energy put into the battery during that time is ~ 60KWH (66 * 0.9)

There is the option of using a Level3 charger, which supplies DC current directly to the battery, bypassing the AC->DC converter onboard the car.. These are not as common as L2 commercial chargers as they are more expensive to install. Using a L3 charger, the Bolt can charge at 55KW, so 0->80% would be around 1 hour. As little as 30 minutes would get you ~100 miles of range. From what I understand, L3 charging can introduce substantial heat into the battery (55KW is a lot of power) and charging that last bit from 80->100% takes a while as the charge tapers off while they manage battery temps.

Anyway, hope this helps some. The Bolt is fairly typical I think (maybe a little on the slow side charging wise), I know the Nissan Leaf has charging numbers that are reasonably close to the above, or are at least in the same ballpark.

 

[electrofelon]

Funny story about charging: so small town near me (real small, village technically) has this community center type building and they put in a free Ev charger. A friend of mine lives there, and has a Tesla. It's probably the only EV for a dozen miles. Anyway so he starts using the charger at times. Eventually he gets flack from the village board over his use of the charger. It's like, guys, what exactly were you expecting would happen when you put in a free public charger??

 

[Hv&Lv]

Funny story about charging: so small town near me (real small, village technically) has this community center type building and they put in a free Ev charger. A friend of mine lives there, and has a Tesla. It's probably the only EV for a dozen miles. Anyway so he starts using the charger at times. Eventually he gets flack from the village board over his use of the charger. It's like, guys, what exactly were you expecting would happen when you put in a free public charger??

Funny thing...
If the village board members owned an EV they would use it as much or more than he does and expect no one to say anything about it.

 

[hillbilly1]

When I was installing a lot of them years ago, they said the rate would be the equivalent to the cost of gas. Last year I was repairing some at Georgia Power, the employees had a swipe card to enable the charger in the parking deck. The public chargers were GridPoint if I remember correctly, and had credit card readers.

 

[jim dungar]

Technically, only utilities can charge for electricity, and some laws have/had to be changed to allow private companies to sell electricity.

I believe almost anyone can apportion a utility bill based on sub metering or some other method, if not simply resell at cost.
Utilities are the only ones that are allowed to make a profit.

 

[hillbilly1]

I believe almost anyone can apportion a utility bill based on sub metering or some other method, if not simply resell at cost.
Utilities are the only ones that are allowed to make a profit.

Exactly. I may have not made that point. Thanks!

 

[hillbilly1]

Sorry, it’s Chargepoint, not GridPoint.

 

[Hv&Lv]

I believe almost anyone can apportion a utility bill based on sub metering or some other method, if not simply resell at cost.
Utilities are the only ones that are allowed to make a profit.

Many states allow others to make a profit reselling electricity
Marinas and RV resorts are a couple.
NC just recently passed a law that allows the EV charging stations to resell at a profit without registering with the utilities commission.
they joined about 30 other states that allow that now

we’re going to see how the free market handles it

 

[wwhitney]

Using a L3 charger, the Bolt can charge at 55KW, so 0->80% would be around 1 hour. As little as 30 minutes would get you ~100 miles of range. From what I understand, L3 charging can introduce substantial heat into the battery (55KW is a lot of power) and charging that last bit from 80->100% takes a while as the charge tapers off while they manage battery temps.

From what I understand, the tapering starts at more like 50% or 60% SOC, so you can't actually get from 0% to 80% in 1 hour. But the tapering does get a lot greater around 80%. If you DCFC at a sufficiently powerful L3 station that displays the instantaneous rate, you can take your own observations about the tapering curve.

Cheers, Wayne

 

[hillbilly1]

Many states allow others to make a profit reselling electricity
Marinas and RV resorts are a couple.
NC just recently passed a law that allows the EV charging stations to resell at a profit without registering with the utilities commission.
they joined about 30 other states that allow that now

we’re going to see how the free market handles it

At the time I was installing them, they were working on that. Been probably 7 or 8 years ago. They said that was the hurdle they were overcoming.

 

[rnatalie]

I've had an electric car for six years now. Most are either "free" or you use one a card specific to the franchise providing the charger which bills your card on file. I've got a half a dozen cards/tags in my car that will work a variety of charger systems.

As for the cost, I figure that the equivalent amount of electricity that would replace a gallon of gas is about 70 cents (this was again five years or so again when I first got the car). I also determined that even with the large amount of coal in my local utility, I'm doing better on carbon footprint than any car that's not getting 60MPG burning gas.

 

[Hv&Lv]

I've had an electric car for six years now. Most are either "free" or you use one a card specific to the franchise providing the charger which bills your card on file. I've got a half a dozen cards/tags in my car that will work a variety of charger systems.

As for the cost, I figure that the equivalent amount of electricity that would replace a gallon of gas is about 70 cents (this was again five years or so again when I first got the car). I also determined that even with the large amount of coal in my local utility, I'm doing better on carbon footprint than any car that's not getting 60MPG burning gas.

Serous questions here if you have had it that long..
I could look this up but it’s better from an owner..

How long is your longest trip in the car?
Any problems with batteries?
replacement on batteries at all? What’s the life?
Would you get another one? Any headaches with it?

 

[retirede]

From what I understand, the tapering starts at more like 50% or 60% SOC, so you can't actually get from 0% to 80% in 1 hour. But the tapering does get a lot greater around 80%. If you DCFC at a sufficiently powerful L3 station that displays the instantaneous rate, you can take your own observations about the tapering curve.

Cheers, Wayne

Picking a few nits here:

Tapering generally only occurs on DC Fast Chargers (DCFC), not level 2. On my Mach-E, tapering begins in earnest at 80%. Other cars / chargers may vary somewhat.

While many people like to call DCFCs “level 3 chargers”, “level 3” is not an official term for a type of charger. Since DCFC is the next level up from a level 2, people just started saying “level 3”. Level 1 and level 2 supply AC to the charger built into the car. As the name implies, a DCFC supplies DC to charge the battery directly.

 

[wwhitney]

Tapering generally only occurs on DC Fast Chargers (DCFC), not level 2. On my Mach-E, tapering begins in earnest at 80%. Other cars / chargers may vary somewhat.

My comments were in the context of DCFC. But I see I wasn't clear that my threshold comments were specific to the Bolt. There have been some complaints that the Bolt starts tapering too aggressively, at too low a rate of charge.

Not sure about Level 2, any tapering would be at very high (user) SOC, like 98%. But a car with a 60 kWh battery and 6.6 kW charger maybe able to maintain the full 6.6 kW charge up to 100% (user) SOC. If left plugged in, there may subsequently be an extended period of brief sporadic charging as part of cell balancing.

Cheers, Wayne

 

[retirede]

My comments were in the context of DCFC. But I see I wasn't clear that my threshold comments were specific to the Bolt. There have been some complaints that the Bolt starts tapering too aggressively, at too low a rate of charge.

Not sure about Level 2, any tapering would be at very high (user) SOC, like 98%. But a car with a 60 kWh battery and 6.6 kW charger maybe able to maintain the full 6.6 kW charge up to 100% (user) SOC. If left plugged in, there may subsequently be an extended period of brief sporadic charging as part of cell balancing.

Cheers, Wayne

Makes sense.
I’ve read of similar premature tapering issues on MMEs as well, but I’ve yet to experience it.

 

[tortuga]

Its apparently less than you would think.
We put some chargers in a few years ago now,
they track kWH with a revenue grade meter and have a fancy card payment system.
I might have an old thread about it here.

When the owners looked at what they were paying for in kWH with people charging
compared to the monthly fee for the 'payment solution'
I.E. data connection, credit card processing, then the card fees they pay on each transaction,
they had me disable the card readers and make them all free chargers.
I can't recall what the numbers were.

But for a housing complex I bet its more worth recovering the cost.