Building the OpenEVSE 240v charger


 After 6 years, my Juicebox level 2 charger gave out. It appears that the little Arduino module was not sending back the information to tell the car things are ok.

I did have some issues making the GFCI circuit work on the Juicebox, very touchy, so after double checking the car and the charging cable, I went to and found they sell the components, so I could re-use my nice metal case, the relay, power cords, and just replace the Arduino brains, plus get a new GFCI sensor (they are current transformers) with the self test, and I added the LCD display since it has some controls, and that the push button for the menu system is hooked to the LCD module.

This is the new main module:

Note that it has the power supply built in, and can be powered from 120 or 220 volts. As compared to the Juicebox board, it is more "connectorized".

The GFCI has more windings on the self test wire, and again comes with the cable and connector attached:

And the LCD module:

The 4 pin connector is to the Arduino board, and the 3 pin goes to the menu push button. Notice the metal holder for a coin cell... this keeps the clock going when power is disconnected. Use a lithium coin cell  CR1220 or CR1225



First, the OpenEVSE website site is not very updated. Many diagrams and pictures are old. For example, the main board on the site is shown as a V4, but I got a V5 in the mail.

But the documentation is all out there on the web, and once you find the locations, it's not really too hard.

I found the V5 layout on the web:


 And below is the connection diagram:



 So in a few minutes, it was up and running. The email support was GREAT, so if you have questions after ordering, email.


The software was pre-loaded on my system. The version is listed as:

Button Menu

I've copied this here just for my reference.

Menu options can be accessed with the push button switch. The menu operates on Long press and Short press.

All options are available in the "Ready" State. If a vehicle is connected only session options are available. (haven't got the full list of what these are, but program without a car connected, except maybe auto charge times)


Long Press - Press and hold down

Short Press - Press and release

  • To access the menu Long press until the menu displays.
  • Scroll through the options with a Short press the button.
  • Select a value to change Long press.
  • Scroll through the available values for that particular option Short press.
  • Select the desired value Long press.

Button Menu Options

(1) Delay Timer

(2) setup

a) Set Time (Day, Month, Year, Hour, Minute) Requires RTC Clock - Deluxe Kit - Color LCD

b) LCD Type (Monochrome, RGB)

Monochrome - Single Color LCDs
RGB - Red, Green, Blue LCDs

c) Service Level (L1, L2, Auto)

L1 - Level 1 Charging Only (120v)
L2 - Level 2 charging Only (200 - 240v) Recommended for International Users
Auto - Auto Detect L1 or L2

d) max Current (Max 40A. Do not exceed 80% of Circuit/Breaker Rating)

e) diode check

f) Vent Required (Enabled, Disabled)

g) Ground Check (Enabled, Disabled)

h) Stuck Relay Check (Enabled, Disabled)

i) GFCI Self Test (Enabled, Disabled)

j) Temperature Check (Enabled, Disabled)

k) exit

(3) restart

(4) exit



below are some menu items I have not found yet, but maybe I need to put the system in either connected or disconnected state.

  • Start Time (Hour, Minute) Requires RTC Clock - Deluxe Kit - Color LCD
  • Stop Time (Hour, Minute) Requires RTC Clock - Deluxe Kit - Color LCD
  • Session Options
  • Charge Limit (add xxx kwh) Requires Current Measurement coil - Deluxe Kit
  • Time Limit (charge for xx minutes)

    For Advanced users only with specific need. The following safety features are enabled by default. Do not disable under normal circumstances. Any disabled Safety Features will be displayed on every boot.Normally you leave all these enabled, although not completely sure on vent required.



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