Friday, April 24, 2015

EV Charger Sharing Made Easy

EV Charging Hangers are a simple, low-cost solution to a nagging problem for some electric vehicle owners
As recent as six years ago, there were probably less than 3,000 highway-capable electric cars on public roads in the US. Since 2010, over 300,000 fully electric and plug in hybrid electric vehicles have been bought or leased in America.

During that time, the number of public charging stations has increased dramatically and we now have tens of thousands of public charging stations across the country. It's a good start, but there is a long way to go before there are enough charging locations to service the ever-growing electric vehicle market. On average, each month more than 10,000 plug in electric vehicles are sold, increasing the disparity between plug in vehicles, and public charging locations.

It's good news that the vast majority of EVs don't need to use public charging, at least regularly. However for those that do, finding an available and working public charging station can sometimes be a challenge. Then there are the times when you pull up to a charging station in desperate need of a charge, only to find that there is a car already plugged in. You immediately start wondering, "Does that car REALLY need to charge like I do, or are they just opportunity charging to top off the battery?" The urge is there to just unplug the other car and plug yours in, especially when that other car is a PHEV. If it's a PHEV, it really doesn't need to charge, since it can operate just fine on gas. But they were there first, and it's not right to unplug (or even touch) another vehicle without permission, even if they don't "need" the juice like you might.

They say necessity is the mother of invention, and recognizing this to be an issue led some electric vehicle owners to begin employing "charger sharing" techniques. This actually dates back to the old GM EV-1 days in California. Owners would leave notes on their dashboard stating a time when it was OK to unplug their car. Others would simply write, "I'm opportunity charging; unplug me if you need to." For the most part this worked pretty well, but that was when there were a few hundred electric cars to service and it was easier to self-police with such a small number of cars on the road. Now, with hundreds of thousands of electric vehicles it's more complicated, and many EV owners haven't even thought of the concept of charger sharing.

One electric vehicle owner, Jack Brown, has indeed thought about this, quite a lot in fact. Jack came up with the idea of connector hangers which an EV owner could use to let others know whether or not they can unplug their vehicle and share the charger. After a few revisions, a two sided hanger was developed which the owner hangs on the J1772 connector and offers instructions on whether or not another EV owner can unplug their car if they need to. One side states "OK TO UNPLUG" with instructions on when it's OK, and the other side says "DO NOT UNPLUG." On the "OK TO UNPLUG" side, you can write the time when your car will be charged enough to allow someone else to use the EVSE, and even leave your phone number so the other person can text or call you if necessary. Jack sells them through his site You can buy them individually or in a ten pack. They are reusable with dry erase markers which just wipe off clean.

From Take Charge and Go Website:

Electric vehicles are becoming more popular and it is becoming increasingly difficult to find an available public EV charging space. Good etiquette by the user community is vital as the infrastructure catches up with demand.

Take Charge and Go EV Charging Hangers are an excellent way to indicate to other Electric Vehicle drivers know how long you will be charging and to share proper etiquette. Simply plug your car in with the hanger on the charging port or dashboard of your car and let others know when you can share the spot.

The charging hanger is made from durable 120# recycled Forest Stewardship Council (FSC) certified recycled paper card stock

  • The hangers are printed on both sides to indicate whether you are necessity charging (RED – DO NOT UNPLUG) or opportunity charging (GREEN – OK TO UNPLUG)
  • The color coding makes it easy for fellow EV drivers to tell if they can share the plug

  • A keyhole cutout provides a sufficient fit for most J-1772 charging handles. A slip-on cutline is provided for easier installation and removal while charging

  • The red DO NOT UNPLUG side has space to write what time you should be done charging with a dry erase marker or a post it note

  • Both sides have a space to leave contact information and provides tips for good etiquette
    • Never park in a charging space if you are not charging
    • When charging in public, limit your charge, don’t charge to your limit. Move on so others have the opportunity to to charge
    • Never unplug another car without permission

  • A QR code and website link are provided for additional information about public EV charging and different car brands charging indicators

  • Hangers are UV coated provide protection from the elements and work well with permanent and dry erase markers and post-it notes to leave information

  • Designed and Made in the U.S.A.
The hangers are currently available in a ten pack for $19.99
If purchased individually they currently cost $2.49, and a ten pack is $19.99. They seem to be made well with a durable coating. I believe they will last a long time even when used in the rain and snow. However there is still one issue with charger sharing. Some new electric cars have chargeports that lock the connector to the vehicle while charging, preventing charger sharing. I do understand the reasoning for this, but I believe it's a flawed feature if the owner cannot override it when they choose to. There should be a setting in the car that allows the owner to unlock the connector from the car while charging if they wish to. This is a perfect example of OEMs not listening to the customer. I totally understand why an engineering team would have never even thought of charger sharing, so it's easy to understand why some EVs don't allow connector unlock. However it's time the OEMs start listening to the EV community and employ the features unique to electric vehicles that improve the EV ownership experience.

My i3 is one of those cars that doesn't allow the connector to be removed unless the doors are unlocked. However BMW has listened to their customers, and will soon be rolling out an update that will unlock the connector once the charging session is complete. This is good, but it's really only halfway to the proper solution in my opinion. I want manual control of whether my connector is locked to the car. It should be a setting in iDrive with a box that I check or uncheck if I want the connector locked to the car or not. They can even make the default setting locked if they are concerned someone will forget they unlocked it one day and end up with an uncharged car because someone unplugged them without permission. Unlock after charging is complete is a step in the right direction, but I'll continue to lobby BMW to finish the job and offer owners full control over their chargeport.


  1. These are great but the car needs to unlock the cable. The eGolf locks it to the car like the i3 also I have one and this is very annoying

  2. Spot on as usual. Good article. Thanks

  3. I just got the new march software update. This is what I have seen as far as charger locking. When you plug in and begin charging the charger remains unlocked, even when the car is locked........ when charging is complete, the charger locks....... I think someone got confused over at the BMW eng team?

    1. Yeah, the connector unlock feature isn't functional yet. I believe its going to be in an update in about three months.

  4. The idea is good since not everyone uses PlugShare, but it is not new. It could have been without the etiquette nagging and the patent pending as "do not disturb" and "wash my linens" tags have been on hotel room doors forever.

  5. In the EU drivers use their own cables to plug in to public chargers. Most likely the reason they stay locked. A setting in the car would be best.

    1. Yes, this is an important fact. I believe it's a big part of the reason why BMW designed the car to lock the connector to it. In most European charging locations, the EV driver supplies the cable for public charging. They plug one end into the EVSE, and the other into the car. For this, a locking connector is needed so people cannot steal your charging cable.

      However in the US, we don't carry our charging cables with us, they are always tethered to the EVSE so they cannot be stolen unless someone were to cut the electrical cable. The exception is when we are using the occasional use 120v EVSE, but these generally aren't used in public charging locations. There are exceptions, but for the most part, the OU 120V EVSE is mostly used at home or in a secure location.

      I believe the engineers designing the i3 simply didn't consider the possibility of charger sharing, or were primarily focused on European customers, perhaps because that's where they live! In any event, EV owners in the US want control over when their connector is locked to their car. They want the ability to set it unlocked if they prefer.

      Actually if you want the best solution, allow the smartphone app the ability to unlock the connector and we can leave a note with our number on the dash (or hangtag) and when someone sends a text we can remotely unlock the connector if our car is charged enough. This isn't hard stuff, a premium car should have this functionality.

  6. Tom, thanks for these very useful tips and for references to vendors who improve our i3 experience. More please.

  7. the control to lock and unlock it in the phone app is a great idea. i still want it locked as sometimes i charged on friends driveway and dont have to worry that the cable will be stolen.

  8. Nice Post.
    I enjoy to seeing photo and valuable information.
    Thanks for sharing with us.
    Tyre dealer Auckland

  9. This is an excellent post I seen thanks to share it. It is really what I wanted to see hope in future you will continue for sharing such a excellent post 먹튀폴리스

  10. Thumbs up guys your doing a really good job 이기자벳