Adding a Button to a Non-Tesla Mennekes (Type 2) plug.

I explain below how to fit a button to a non-openable Mennekes (Type 2) plug, from my EV Supply Equipment (EVSE), so as to tell a Tesla Model 3 to stop charging and release the charging plug from the Tesla.

I am happy to report that my existing non-openable mennekes charging plug can be opened using a fine tooth saw to cut all around the plug casing at the point of what appears to be the plug's serial number under the barcode. Obviously this needs to be done very carefully so as not to cut the wires inside the plug. Not only does the outer case need to be cut through but also a number of small ribs inside the outer case need to be carefully cut. It is also necessary to remove the three screws holding the cable tight and the cable clamp in order to pull the handle part of the case back in order to have more room to work when installing the button. I bought the waterproof normally closed push button switch for $A2.32 via eBay

The normally closed push button can then be fitted which, when pushed, will break the wire leading from the resistor to the PP terminal. Although the button will not open the charging door when wanting to plug the EVSE into the car, pushing the button will unlock the door whether the car is either charging or not charging from the EVSE thereby enabling the plug to be more easily unplugged from the car.

I am happy to wear any warranty implications because of the convenience of not having to wait for the app to open or reaching inside the car to unlock the charging door to finish charging my Tesla Model 3.

One obviously has to decide whether to attempt this modification based on one's level of competence and the likelihood of any possible impact on the EVSE's warranty.

Worth noting is that this modification does not "talk" to the EVSE but rather to the Tesla. The installed button, when pushed, temporarily breaks the wire going from the PP terminal in the charging plug to the Earth terminal in the plug. This action tells the Tesla to stop drawing power from the EVSE and unlock the charging plug from the car's charging port.

The wiring information came from the post below by arg on the Tesla Motors Forum.

"For the cable unlock-to-unplug function only, it is fairly easy - provided you have a connector that you can actually open up (many have security screws of one sort or another; some are moulded and so impossible to open).

If you do get it open, you will find that there is a 220R resistor between the central earth pin and the 'PP' pin.

The minimal change (ie. to make it actually work) is to insert a normally-closed switch between the PP pin and the resistor. So in the normal state there is the 220R between those pins as before, and with the button pressed the PP pin is disconnected. Model S is happy with this and unlocks the connector without any errors etc."

Webmaster's Note: The resistor varies depending on the capacity of the cable. 1,500 ohms = 13 amps limit, 680 ohms = 20 amps limit, 220 ohms = 32 amps limit and 100 ohms = 70 amps limit.

Video of Button in Action

Video of Button in Action

Awkward action is because plug is only held together by tape during testing stage.

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