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A Brilliant and Simple Idea To Improve Charging Station Efficiency for Electric Car Drivers

Here is a case. Electric car is parked at a charging station and fully charged. It has been two hours and the owner has not returned yet. Other EVs are not able to charge. What do you do? Here is, what I think a brilliant and a very simple idea charging stations can implement to improve EV charging efficient and avoid issues like this.

But first, let's look at the case, presented by Rod Gayutin from Corona, CA at the LEAF Owners public group on Facebook.

EV is 100% charged. What do you do if the EV owner is taking advantage of a level 2 charge point station. Car is parked for more than 48 hours in a drug store. Store does not own the station. A sign from the store that says maximum of 30 minutes for customers only, otherwise it will be towed by the owners expense. Do you have EV etiquette?

Daniel Papania proposes multi-charge setups

Not that I am trying to defend poor parking practices, but I think that the public charge station/parking spot behavioural mechanics weren't really though through very well. Often when someone arrives at a destination, they will be parked for several hours until they return and they don't have the option to return to their car within 2 hours.

I don't understand why the charge point stations aren't designed to serve several bays. So for example, lets say you have 8 parking bays all next to each other. then you have 1 charge point machine with 8 charge cables coming out of it. When you arrive, you park in any of the 8 stalls and plug one of the cable into your car. If another car arrives while you are charging, they can still park and plug in, but their car won't start charging until yours is done - at that point the charge will automatically switch to the next car in order.


Stuart Evans (not verified)    December 17, 2015 - 11:47AM

It sounds OK, but it sounds like a solution driven by the EVSE manufacturers to increase sales of fancy new equipment. How about putting a 110V outlet by the parking spots so anyone can plug in when they want to.

Richard Lowenthal (not verified)    December 17, 2015 - 11:22PM

In reply to by Stuart Evans (not verified)

If you have 8 cars on one level 2 charging station and each one takes 2 hours to charge, that poor eighth guy has to wait 16 hours.

ChargePoint has this functionality for a two-stall case but it charges each car at 20 amps until one car finishes, then it charges the remaining car at 32 amps.

On the other hand, if you use 120 Volts 12 amps for charging then it will take you 10 hours to charge your car enough to go 50 miles.

Since over half the cost of a charging station is digging the trench, charging at higher rates and getting more cars to go through makes a lot of sense.

HarryS (not verified)    September 8, 2020 - 8:04PM

In reply to by Richard Lowenthal (not verified)

My Leaf has an “AUTO” lock on the SAE L1/L2 charge port. When the charge is 100% it releases, allowing a car parked next to mine to unplug from mine and to plug up.
Hopefully the charging station can tell when one car is disconnected and another connected. I don't want to pay for charging someone else’s car.
We really need to have a caller that rings up the cell phone to tell the driver that his car is charged. If I am where I can see the blue lights on my dashboard, I can tell if it's charged.

Ed Zimmer (not verified)    December 17, 2015 - 7:22PM

Stuart - While that may be the case (EVSE sales going up) this will need to happen eventually to help support the adoption of EVs. Putting a 110v outlet by the parking space would be free power from the property which not all properties would be willing to do and its not scalable.

The article provides a decent solution but why not take it one step further with power management. In this scenario if 8 cars are plugged in they divide the power 8 ways. When each car finishes charging its power is than shifted to the other cars and so. Public charge stations will always have this issue until they become more plentiful or go with ridiculous charge by the minute policies that would punish you for leaving your car parked for such long periods of time. Hopefully EV drivers have a charger at home that is able to sustain them for their daily trips and they don't need to be reliant on public charging.

Richard Lowenthal (not verified)    December 17, 2015 - 11:25PM

In reply to by Ed Zimmer (not verified)

The highest utilization for a charging station is achieved if they pay something by time. So for example if you charge 25 cents an hour, people who don't need a charge won't plug in, and people who are finished will move their car. And at 25 cents an hour, those who do need a charge are getting a bargain.

Thomas Earle Moore (not verified)    December 18, 2015 - 9:45AM

In reply to by Richard Lowenthal (not verified)

+1. Multiple bays are the way to go, as Tesla has demonstrated with their superchargers, of which there are never less than two in any single location. But they don't fool around skimping on charger equipment.

James Wagner (not verified)    May 26, 2017 - 11:46AM

Bad idea- Have lots of time to get a charge then a wall outlet is the least expensive infrastructure to add...The charge rate 8 Amps x 120V = 960 Watts per hour at 12Amps 1440 Watts per hour...Level 2 6600 Watts per hour. ChargePoint offers in their series 4000 machines the ability to wire on just one circuit and if there are two cars charging they share the charge both charging at 3300Watts per hour rather than 6600 Watts per hour...Save on wiring and leave everyone guessing about when their charge will end...Better to let people know what they are getting ahead of time...Level 1 or real Level 2 with a known getterdun time. Better to have $5 per hour penalty pricing for those who stay after their charge is complete,