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tesla gen2 ac charger

The Tesla GEN2 charger is a single/three phase 10kW AC charger that was fitted in the Model S from 2012 until it was replaced in the 2016 'facelift' model with GEN3.

One or two GEN2 chargers are installed beneath the rear seats in the model s for ac charging.

The charger is made up of three 3.3 kw modules, each sitting on a liquid cooling plate. This assembly enables both single and multi phase ac charging.

"Running a Tesla charger at much under 200v dc will cause it to explode. Yes I know the label says 50 to 450v but it lies. Yes I blew one up discovering this."

Charger Dimensions: 500x300x100mm

Replacement control boards

replacement control board

v5 kit:

v5 partially built board:


Charger connection

A1 A2 A3 A4 A5 B1 B2 B3 B4 B5 B6
OUT2 - AC present D1 - enable 12V supply CANH Control Pilot
A6 A7 A9 A10 A11 B7 B8 B9 B10 B11 B12
OUT1 - HV enable GND CANL Proximity
AC DC Connections.jpg

Connector part numbers

AC and DC power connections - housing 044441-2006, pins 0433753001

Logic connectors Molex: housing 10 way 19418-0014, 12 way 19418-0026, pins 33012-2001


you'll need a st-link v2 smt32 programmer. Unofficial ones are cheaply available from amazon and ebay.

st-link programming utility:


Two options:

  1. Charger_gen2_v5.hex
  2. Or commercial software:

Click "Target --> Connect" from top menu. You want to see the screen get filled with a data dump of symbols. In the upper right of the screen you can see it identified the device.

In the main viewing window are multiple tabs, click the "Binary File" tab to select it.

This will ask to open a file, you choose: "stm32_loader.hex" from, download ahead of time. This will change what shows up in the viewing window.

Click "Target --> Program and Verify" from the top menu. This pops up a window, and you can probably just click "Start" on that window. This programs the STM32 chip with the stm32_loader.hex file.

The STM32 on your v5 gen2 Tesla charger Board can now load other files.

You can close the stm32_loader.hex tab, and go back to the "Binary File" tab, which will ask to open another file.

You choose: "Charger_Gen2_v5.hex"

Same as last time, click "Target --> Program and Verify" from the top menu. And click Start.

The STM32 on your v5 gen2 Tesla charger Board now also has the software to run.

You are now done with the ST-Link USB dongle, it's no longer needed.

Future updates can be done via wifi. (must have esp8266 wifi module programed )

External CAN bus

Gen2 Charger V5aB2 logic board with CAN wired to external pins

The V5aB2 version of the board has no connection to the external CAN bus (V5aB3 has) but you can add it with to bodge wires as shown in the picture. You will find CANH and CANL on the 3 pin header underneath the wifi module. Route them over to CONN6 as shown. CONN2.1 (CANH) is connected to CONN6.24, CONN2.2 (CANL) to CONN6.26.

Revision V4aB3 does not need this modification. If you do NOT use the external CAN bus on that version remember to close the solder jumper next to R1 under the Wifi module.

If the charger is the first/last device on your CAN bus there is nothing else to do. If it is somewhere in the middle you have to remove the bus termination resistor R1.

Before doing this be aware that all internal CAN traffic is also seen on the external CAN bus. The following IDs are already used and mustn't used by any other device on the bus:

207, 209, 217, 219, 227, 229, 237, 239, 247, 249, 327, 329, 347, 349, 357, 359, 367, 368, 369, 377, 379, 537, 539, 717, 719, 20B, 21B, 22B, 23B, 24B, 32B, 34B, 35B, 36B, 37B, 42C, 43C, 44C, 45C, 53B, 71B.

Functionality of external CAN bus

With the CAN bus now available externally you can remote control your charger via CAN and also receive some values from it. The mapping is similar to the CHAdeMO CAN protocol. The feature is only available in the commercial firmware.

Charger CAN protocol
ID Direction Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7
0x102 Receive by charger DC voltage limit MSB DC voltage limit LSB DC current set point ==1 enable charging SoC
0x108 Transmit by charger Version=0 Max DC voltage MSB Max DC voltage LSB Max DC current
0x109 Transmit by charger Version=0 DC voltage MSB DC voltage LSB DC current 0 when off, 5 when charging

Doesn't belong here, will

move to Byte 5 after 1.06.R!

Like Byte 4

for versions

after 1.06.R

Example: transmit "0x102 # 0 0x1 0x86 0x14 0x1 50 0 0" to enable charging up to a voltage of 390V and a DC current of 20A, report SoC of 50%.

Parameter view of commercial firmware

Commercial charger firmware

In addition to the open source firmware there is also a commercial firmware. It adds advanced features:

  • Support for the standard open inverter web interface
  • Parameter handling as known from the inverter firmware (see picture)
  • Spot value handling like inverter including plotting, gauges, and logging
  • Over the air update like inverter
  • DC current control
  • CAN control as described above

The firmware requires the board to be flashed with stm32_loader.hex. An Olimex MOD-ESP8266 must be programmed with the openinverter web interface. See Olimex MOD-WIFI-ESP8266 and this forum thread for flashing instructions. With that done, future updates will happen via the web interface.

Connecting to the Web interface

Depending on the version of your Olimex wifi dongle they are "open" or you need a password to connect.

By default you can connect to the network (Acces Point) and browse to:

By default all charger kits will have SSID : charger PASSWORD : charger123

Note: Its recommend that you change it. No body wants to drive and have some joker with a phone finding this information and accesing your charger.


If you bought a fully assembled V5aB3 board from the EVBMW webshop you can skip this step.

Tesla Charger Serial.png

The firmware will work without registration but charging time is limited to 5 minutes. To overcome this, a board-specific pin must be bought. In order to do this the firmware and web interface must be installed and working.

Go to the openinverter webshop and check out as many pins as you need. When checking out add the serial number(s) of your board(s) in the order option. You will find the serial number on the bottom of the page as last spot value.

You will then receive an email containing one pin for each board. Enter the pin in the web interface in the "pin" parameter. When the pin is correct it will be automatically saved to flash and your board is ready to be used.

Commercial firmware usage manual


The firmware exports a number of parameters to be modified by the user. All modifications are temporary until you hit "Save Parameters to Flash" at the top of the page.

We will go over all of them.


This parameter is mainly relevant for CAN operation. It is transmitted via CAN to let the vehicle know how much DC current the charger can deliver. Each charger module maxes out at about 15.5A so the maximum total charging current is 46.5A. Since the total power is also limited to 10 kW it depends on the output voltage as well. There is no need to be exact on this, the firmware will automatically limit the AC input current to each module to the hardware maximum.


This is the per-module AC current limit. When charging from a 3-phase outlet (see below) each module will be allowed this current. When charging from single phase, this current will be equally distributed between the enabled chargers.


DC charge current limit. An additional limit to charge power. It is also mapped to the CAN bus so if you have a BMS that calculates a maximum charge current you can forward this to the charger.


Here you can program which charger modules you want to enable. It is a flag channel, so 1 means "Module 1 enabled", 2 means "Module 2 enabled" and 4 means "Module 3 enabled". Combining these flags enables multiple modules, e.g. 5=4+1 enables modules 1 and 3. 7=4+2+1 enables all modules. This is the default. The parameter can not be directly changed, but you have to type "set chargerena 5" next to where it says "Send Custom Command" on the top of the page and then press the button.


This modifies the constant voltage setpoint of the chargers. This value is transmitted directly to the modules without further processing. It lets you add a constant voltage phase to your charge process. When reaching this voltage the chargers will control the current to maintain this voltage.


This parameters specifies a charge end condition. When the voltage is hit the charging process stops and will not resume until you re-plug the charge cable. If you wish to add a constant voltage phase and control charge end by your BMS, set this parameter higher than udcspnt.


Another charge end condition. Charge only for the specified time in minutes.


  • Type2: Specifies one or more modules are operated on ONE common phase of a Type-2 EVSE. The limits imposed by cablelim and evselim (pilot signal) are distributed equally over the enabled modules. For example if you enable all 3 modules, the cable allows 32A but the EVSE only allows 16A, every module will run at 16/3=5.3A. Charging will start automatically as soon as proximity and a valid pilot signal is detected.
  • Type2-3P: Specifies each module is connected to a different phase of a Type-2 EVSE. The limits imposed by cablelim and evselim are allowed for each module.
  • Type1: Like Type2 but cablelim is always assumed 40A.
  • Manual: Specifies one or more modules are operated on ONE common phase, power is distributed like in Type2 mode. Charging starts as soon as the enable pin "D1" goes high. iaclim MUST be configured to the limits of your AC source as there is no automatic detection like in Type1 or Type2 modes.
  • Manual-3P: Specifies that each module is connected to a different phase of 3-phase outlet. Each module is allowed iaclim AC current. iaclim MUST be configured to the limits of your AC source as there is no automatic detection like in Type1 or Type2 modes.


When on, expect charging instructions via CAN message 0x102 as described above. Charging will start when the enable bit is set. when no CAN message is received for 1s, charging will stop. Note that the digital enable input "D1" also needs to high to allow charging. Also the autostart conditions apply when enabled.


Can be used to tune the control loop of the DC current PI controller.


Software pin, obtained by registration.