Megacell Charger

$ curl -X POST http://10.10.10.30/api/get_config_info
{
  "MaV": 4.2,
  "StV": 3.7,
  "MiV": 3,
  "DiR": 1000,
  "MaT": 40,
  "DiC": 1,
  "FwV": "Firmware V4.3.0.11",
  "FirmwareVersion": "Firmware V4.3.0.11",
  "ChC": false,
  "LmV": 0.3,
  "LcV": 3.6,
  "LmD": 1.1,
  "LmR": 90,
  "McH": 240,
  "LcR": 1000,
  "CcO": 1,
  "DcO": 1,
  "MsR": 250,
  "MuL": 0
}

The parameters here are set in the "Settings" menu of Megacell Monitor UI in two different windows - "Charger Settings" and "Circuit Breaker". They meaning of particular codes is as follows. For some parameters the minimum and maximum values permitted by the UI have been documented. It is not known whether these limits reflect limitations of the hardware or firmware in the Megacell Charger or whether they are what the developers considered "sensible".

Parameter code	Name in Megacell Monitor UI (in Settings)	Default value in Megacell Monitor UI	Value restriction in Megacell Monitor UI	Notes
MaV	Charger Settings -> Max Voltage (V)	4.2
StV	Charger Settings -> Store Voltage (V)	3.7
MiV	Charger Settings -> Min Voltage (V)	3
DiR	Charger Settings -> Max Discharge (mAh) (sic!)	1000
MaT	Charger Settings -> Max Temp (C)	40
DiC	Charger Settings -> Discharge Cycles	1
FwV	Charger Settings -> Firmware version			Cannot be changed in UI
MuL	Charger Settings -> Multicast enable	0
ChC	Not presented in UI directly			Chip-controlled charging enable
LmV	Circuit Breaker -> LVC Minimum voltage (V)	0.3	min 0.01, max 3.0
LcV	Circuit Breaker -> LVC charge voltage (V)	3
LmD	Circuit Breaker -> LVC Max voltage drop (V)	1.1
LmR	Circuit Breaker -> LVC Max trickle time (minutes)	90	min 5, max 180
McH	Circuit Breaker -> Max Charge time (minutes)	240
LcR	Circuit Breaker -> Reject cells with low capacity (mA) (sic!)	1000
CcO	Charger Settings -> Charge Correction Factor (%)	1
DcO	Charger Settings -> Discharge Correction Factor (%)	1
MsR	Circuit Breaker -> Max ESR value (mΩ)	250

A request very similar to getting charger configuration is used to set it. As an example:

$ curl -i -d '{"McH": 240, "LcR": 1000, "LmR": 90, "CcO": 1, "DcO": 1, "LmV": 0.3, "LcV": 3.6, "LmD": 1.1, "ChC": false, "MaV": 4.2, "StV": 3.7, "MiV": 3, "DiR": 1000, "MaT": 40, "DiC": 1, "MsR": 250, "MuL": 0}' -X POST http://10.10.10.30/api/set_config_info
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 8
Connection: close

Received%

When the operation is successful the charger replies with a 'Received' string. When the JSON content is invalid, an error response is sent back:

$ curl -i -d 'fdsgdd' -X POST http://10.10.10.30/api/set_config_info
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 6
Connection: close

failed%

Partial settings updates are possible, for example in order to change the value of a single parameter (for example McH) the following request can be sent:

$ curl -i -d '{"McH": 100}' -X POST http://10.10.10.30/api/set_config_info
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 8
Connection: close

Received%

The value limits that are enforced by the UI can be bypassed by sending configuration parameters directly, for example the maximum allowed value for the LmR parameter (max trickle charge time) is 180 minutes. Using the following request a higher value can be set, the firmware doesn't enforce the limits from Megacell Monitor UI:

$ curl -i -d '{"LmR": 200}' -X POST http://10.10.10.30/api/set_config_info
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 8
Connection: close

Received%

This results in the LmR parameter successfully set to 200:

$ curl -X POST http://10.10.10.30/api/get_config_info
{
[...]
  "LmR": 200,
[...]
}

The firmware however imposes it's own limits on the parameter values. For example, when a request is sent attempting to change the LmR parameter to 300:

$ curl -i -d '{"LmR": 300}' -X POST http://10.10.10.30/api/set_config_info
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 8
Connection: close

Received%

This results in a success response but the new LmR parameter value received when the configuration is read does not reflect the initially requested value 300, instead the parameter value seems to be reset to a "firmware-default" which is 90 in this case:

$ curl -X POST http://10.10.10.30/api/get_config_info
{
[...]
  "LmR": 90,
[...]
}

The Megacell Monitor UI contains a button labeled as "Reboot Chargers" which sends the following request:

$ curl -i -d '{ "secret": 20200104}' -X POST http://10.10.10.30/api/reset_charger
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 6
Connection: close

failed

Even though the response indicates a failure the charger does reboot, this can be noticed on the LCD as well as when observing the debug log.

An API request used to fetch the current state for each of the 16 charger slots is used to update the charger view in the Megacell Monitor UI. The request is as follows:

$ curl -i -d '{"settings": [{"charger_id": 1}]}' -X POST http://10.10.10.30/api/get_cells_info
HTTP/1.1 200 OK
Content-Type: text/json
Access-Control-Allow-Origin: null
Access-Control-Allow-Credentials: true
Access-Control-Max-Age: 1800
Access-Control-Allow-Headers: content-type
Access-Control-Allow-Methods: PUT, POST, GET, DELETE, PATCH, OPTIONS
Content-Length: 5334
Connection: close

{
  "cells": [
    {
      "CiD": 0,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 1,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20.32258,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 2,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 3,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20.32258,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 4,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 5,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 21.93548,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 6,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 22.58064,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 7,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 23.87097,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 8,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 23.54839,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 9,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 21.93548,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 10,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 21.29032,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 11,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 19.35484,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 12,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20.32258,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 13,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20.64516,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 14,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 20,
      "ChC": false,
      "State": "Low voltage cell"
    },
    {
      "CiD": 15,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 21.29032,
      "ChC": false,
      "State": "Low voltage cell"
    }
  ]
}

The request parameters are always identical and are likely a future extension point where a single API endpoint will be able to handle multiple chargers each having their own slots. For each slot the following JSON content is returned:

    {
      "CiD": 8,
      "voltage": 0,
      "amps": 0,
      "capacity": 0,
      "chargeCapacity": 0,
      "status": "Not Inserted",
      "esr": 0,
      "action_length": 0,
      "DiC": 1,
      "complete_cycles": 0,
      "temperature": 23.54839,
      "ChC": false,
      "State": "Low voltage cell"
    }

Educated guesses and observation have lead to the following table explaining the meaning of the above fields:

Parameter code	Description	Unit	Valid values	Notes
CiD	Cell slot identifier	N/A	slot C1 - 0
			slot C2 - 1
			…
			slot C16 - 15
voltage	Cell voltage	V
amps	Cell current	mA		Positive when charging, negative when discharging
capacity	Discharge capacity	mAh		Capacity measured during discharge
chargeCapactity	Charge capacity	mAh		Capacity measured during charge
status			- "Not Inserted" when no cell in slot	This is the string displayed on the LCD
			- "New cell inserted" after inserting a cell
			- "LVC start charging"
			- "LVC Charging"
			- "LVC Charged
			- "Cell rest 5 Min"
			- "LVC Completed"
			- "Started Charging"
			- "Stopped Charging"
			- "Hot Charged"
			- "Started Discharging"
			- "Discharged"
			- "Hot Discharged"
			- "Initiating mCap" when capacity test is requested in UI
			- "mCap Started Charging"
			- "Wait For ESR Test"
			- "mCap Started Discharging"
			- "mCap Store Charging"
			- "Store Charged"
			- "Bad Cell" - 'State' describes what was the failure
			- "Overdischarge halt"
esr	Cell internal resistance	Ω
action_length	Time elapsed since action was started	seconds
DiC	number of disch. cycles
complete_cycles	number of completed disch. cycles
temperature	Cell temperature	°C
ChC	Chip controlled charging	boolean
State	Second component of cell state		- "Low voltage cell" when cell voltage is below the minimum for charging	Mostly related to failure conditions
			- "High ESR Error" when ESR during mCap was higher than maximum
			- "HOT charged" and "HOT discharged" when temperature was exceeded during mCap
			- "Low capacity Error" when capacity during mCap was less than minimum
			- "High volt drop Error" when voltage drops more than the maximum during low voltage recovery
			- "Charge time exceeded" when maximum charging time during mCap is exceeded
			- "Healthy" when cell voltage is OK
			- "LVC recovery failed" when LVC has failed to recover the cell
			- "!!!Emergency stop!!!"

Performing actions by the charger on particular cells (for example a charge/discharge cycle or LVC) is accomplished by "setting the cell state" using the following request. In the example below slots 0 and 1 are requested to perform LVC:

$ curl -i -d '{"cells": [{"CiD": 0, "CmD": "alr"},{"CiD": 1, "CmD": "alr"}]}' -X POST http://10.10.10.30/api/set_cell
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 8
Connection: close

Received%

The values of the CmD field correspond to different actions that can be sent to the charger, the following codes have been documented based on what is available in the "New cell insert actions" in Megacell Monitor UI:

Action code	Action name in Megacell Monitor UI	Description	Log message
alr	Start LVC recovery		(Informational) - CellID: 0 - handle_set_cell_state: start lvc recovery
ach	Start charging		(Notice) - CellID: 0 - handle_set_cell_state: Start Charging
sc	Stop charging		(Informational) - CellID: 0 - handle_set_cell_state: Stop Charging
adc	Start discharging		(Informational) - CellID: 0 - handle_set_cell_state: Start Discharging
odc	Stop discharging		(Informational) - CellID: 0 - handle_set_cell_state: Stop Discharging
act	Start capacity test	mCap on charger LCD	(Informational) - CellID: 0 - handle_set_cell_state: Start cap test
omc	Stop capacity test	mCap on charger LCD	(Informational) - CellID: 0 - handle_set_cell_state: Stop cap test
asc	Not available in the Megacell Monitor UI	StartStoreCharge
osc	Not available in the Megacell Monitor UI	StopStoreChrage
dsp	Not available in the Megacell Monitor UI	DisposeStart
dps	Not available in the Megacell Monitor UI	DisposeStop
"" (empty string)	Stop operation

The charger exposes a log on port 8888 (described in detail in the next section). An API request can be used to adjust the log level of messages which are sent to the log. The request is the following:

$ curl -i -d '{"debug_level": "Debug"}' -X POST http://10.10.10.30/api/set_log_level
HTTP/1.1 200 OK
Content-Type: text/plane
Content-Length: 5
Connection: close

Debug%

The debug levels possible correspond to classical UNIX syslog levels (see the 'man 3 syslog' command):

• Emergency
• Alert
• Critical
• Error
• Warning
• Notice
• Informational
• Debug