Repair J1772 connector

BACKGROUND

About three months ago I fell against the J1771. The next morning I found the car had not charged; the plug was at an angle because the latch tooth had broken off. It would still charge our cars but the proximity sense did not work unless I manually remembered to push the latch.

A couple of weeks ago, I bought a replacement J1771 connector from Amazon and installed it on the BMW L1 charger.

Survey Replacement

The first step is to disassemble the replacement. It came in without any instructions so this assumed some degree of understanding.

The shell is held together by Torx screws that were easy enough to remove:


Inside we find a the push button lever that activates a micro switch. This is part of the proximity sense circuit the car uses:


The plug is sealed using triangle screws. So I went to my favorite hardware store and bought a tri-wing bit which worked close enough for this first attempt:


So here is the shell, plug, and plug cover:


With the switch not activated, we measured 150 ohms:


Activating the switch, the resistance increases to 479 ohms that signals the car should stop charging. This avoids "hot" plug and unplugging that can lead to connector wear from small arcing:


Here are the parts of the plug:


There are five pins: ground is on the tab side; at the 2 o'clock position is the proximity pin; at 10 o'clock the pilot signal; 5 o'clock is the 'HOT' pin (black wire), and; 7 o'clock neutral:


This shows how the pins fit in the plug assembly:


Here you see all subassemblies together:


I bought a new stripper sized for power cables and a crimper tool. Sad to say, the crimper did not work out:


(continued due to 20 image limit)

 

Broken Connector

Here we see the broken tooth off the retainer latch:


My Torx bit did not work because of the center pin. So I bought a set of security Torx bits:


The inside of the 2014 model year, J1772 was very busy:


Here is the latch with the micro switch and bundled wires, tie-wrapped together:


Here is the microswitch that converts the red and black wires to a ground and wire for the proximity circuit:


The next problem was the grommet that brought the cable into the handle. There were different sizes and incompatible:


The replacement grommet on the left is sized for a larger cable. The original cable only had to handle 15A so it was much smaller.


My fix was to wrap the cable with plastic tape to increase the diameter. This solved the grommet and internal cable strain relief clamp:


So I threaded the wire through the five connector holes and only needed to crimp the connectors:

Unfortunately the blue, pilot signal wire would not fit through the black plastic hole. So I used a drill to make it a little larger to fit.

There are three different connector styles. The HOT and NEUTRAL pins are identical. The ground pin is longer. Curiously the proximity and pilot pins are not identical:


The proximity pin on the left is slightly smaller than the pilot signal pin on the right:


Try as I might, I could not crimp the pins. So I soldered them:

Due to the size, a strong, solder gun is needed. But these solder cups do not have an air escape hole in the base. Solder can not flow through the whole length of the cup due to the trapped air.

The first plate on the left holds the pins into the connector assembly. A single Torx screw holds it, The comes the orange, water resistant rubber assembly. On the right is the last plate that forms a wall to the interior of the J1772 shell:


Another view showing the single Torx screw:


The water gasket is seated and the back plate ready to compress the gasket:


Here is the unit ready to seal up:


Finally, everything is ready for the smoke test:


CONCLUSIONS

1. Assemble the J1772 using standard wire leading to four, automotive style, crimp connectors. This avoids having to fiddle with threading the power cable wires into the plug and a lot of experimentation.
2. These are solder connectors so drill a small hole at the base of the cup so the solder can flow through and fill it completely. Since I did not do this, I'll use an IR thermometer to make sure there are no temperature hot pins.
3. Wrapping the smaller cable with plastic tape is better than nothing, it is not an optimum solution. I will continue to look for better solutions like liquid tape and hoses whose internal and external diameters to fit.

Bob Wilson

ps. Before doing the smoke test, I noticed the AC plug was discolored so I opened it up:



So much for a water-tight, NEMA 5-15.

 

Repairing the NEMA 5-15, I'm going to directly wire the extension cord to the EVSE and fabricate the repair using crimp connectors and water-tight techniques. Then I'll order another J1772 and modify the pins with a solder vent hole and assemble it with wire cut to fit sized for +30A operation. Inside the J1772 shell there will be four, crimp type pigtails to support rapid installation.

When assembled and ready to go, I'll do a guerrilla repair on the Whole Foods EVSE with a broken J1772. It is currently powered off so the repair shouldn't take more than 30 minutes.

Bob Wilson

 

Over a year ago, eMotorwerks offered what looked to be a TurboCord, dual voltage 3.3kW charger for a reasonable price. I put in my order only to learn they changed their mind about offering the part because the build quality. Disappointed, they offered a refurbished JuiceBox 40 Pro for a fair price and I bought it. Meanwhile, I installed my original JuiceBox 40 Pro at a favorite shopping area and used the portable EVSE at home.

So I repaired the portable EVSE but got more and more unhappy as I discovered the NEMA 5-15 plug was not all-weather. Worse, it was only 12A @120VAC and I really wanted dual voltage 120-240VAC and multicurrent 12-30A EVSE. So I found:
https://www.evseadapters.com/products/16-30a-adjustable-120-240v-charger-evse

At just under $400, I ordered it with adapters for NEMA 5/15 to NEMA 14/50. Meanwhile, I have my spare JuiceBox 40 so I pulled it out and 'lessons learned'.

TEST WIFI NETWORK

I relocated a "T-Mobile 4G LTE HotSpot Z915" from the living room to the dinner room near the JuiceBox. But there is a kitchen with a lot of metal between it and the nearest cell phone tower. When I could not connect the JuiceBox, I got back on the HotSpot and sure enough, no Internet access. Moved to the living room, displaced from the kitchen and sure enough, Internet access.

PROBLEMS WITH APP

This last effort was done late at night so the iPhone would not washout and I could plug and unplug the JuiceBox. There is about a 2-3 minute window when first powered on that the JuiceBox is in a 'roaming' mode and can be configured. Just due to rains in the area, I had to wait until midnight but no big deal.

The normal practice is to use the iPhone app, "EV JuiceNet," to complete linking the JuiceBox to the WiFi network. But regardless of WiFi network, I have two, it always returned an error message that the WiFi password was wrong. After a through investigation, only the JuiceBox was having the problem as WiFi network was working perfectly. Fortunately, there is an alternate approach that does no use "EV JuiceNet."

With my iPhone directly connected to the JuiceBox, a browser pointed to "www.setup.com", gets simple web page served by the JuiceBox. This allows allows selecting the WiFi network from the roaming list and entering the password.

SCRUBBING THE DETAILS

Back in the house, I could see the JuiceBox on the list of connected devices on the WiFi HotSpot. So I fired up the app "EV JuiceNet" and there it was. Using a default name, I could see it idling so I backed up the Prius Prime and charged the battery:


For good measure, I configured MAC address filtering on the HotSpot so only the iPhone, primary Macintosh, and the JuiceBox can connect. A 'war dialer' may see the network but not able to connect.

I need to run a power cycle test to make sure everything comes back up correctly. If it does, I'll probably configure the HotSpot to minimize broadcasting the SSID. This is not 100% effective compared to the MAC filter but just another layer of sensible security.

Bob Wilson

ps. I will buy a new set of weather proof NEMA 5/15 plug and connector and a small tube of silicon sealant and Rain-X. I have 'liquid tape' to coat the wire connectors. Then I'll assemble it with the silicon sealant to protect the interior. The last will be liberal application of Rain-X to the faces and external wire inlets.