Control library for the Tenma power supplies. The battery-charger tool provides a convenient cross platform (Linux, Windows & OS X) command line user interface to charge most common batteries. The default is set for 250mAh lithium battery, but can easily be changed to fit other types.

--help

Show a help message describing the usage and options of the tool.

--version

Show program's version number and exit.

--verbose-level

Set the verbose level, where 1=DEBUG, 2=INFO, 3=WARNING (default), 4=ERROR, 5=CRITICAL.

--config

Load command line options from a configuration file.

--baud-rate

Set the baud-rate of the serial port (default 115200).

--serial-port

Set the serial port (default '/dev/ttyACM0').

--skip-check

Skip sanity/device checking on start-up.

--discharge

Discharge the battery (default will charge battery).

--max-voltage-power-supply

Maximum voltage the current PSU can deliver.

--precharge-voltage-level

Voltage threshold used to initially pre-charge the battery with the precharge-current-level before going to the constant-current stage. Pre-charge is the first phase were the battery is checked for proper behavior.

--precharge-current-level

Current used during the pre-charge phase. The pre-charge stage continues until the voltage reaches the precharge-voltage-level.

--constant-current-level

Current used to charge the battery until it reaches the constant-voltage-level. The constant-current phase is the second stage when charging the battery.

--constant-current-grace-period

Period in seconds to startup the constant-current-level without checking the thresholds. Large capacity batteries might take a few seconds to settle before the actual charging current is reached (default 0 s).

--constant-voltage-level

Voltage from which the charger goes from constant-current to constant-voltage. The constant-voltage phase is the third stage when charging the battery.

--end-of-current-level

Current threshold to determine if the battery is full when in the final (constant-voltage) charging stage.

--soc-empty-voltage-level

Voltage threshold to determine when the discharge cycle has ended.

--max-current

Extra safety check to make sure the configuration set never goes beyond this current. Increase for large capacity batteries to support fast charging.

--typical-discharge-current

Current used for discharging.

--series-connection-resistance

Resistance of the wires when charging or discharging. Used when large currents are used, to compensate for the voltage drop between PSU and actual battery voltage. Tune by measuring the voltage directly on the battery (default 0.0 Ohm).

--series-discharge-resistor

Resistance used for discharging.

--precharge-voltage-level
--precharge-current-level
--constant-current-level
--constant-current-grace-period
--constant-voltage-level
--end-of-current-level
--series-connection-resistance
--max-current

--discharge
--constant-voltage-level
--soc-empty-voltage-level
--typical-discharge-current
--series-connection-resistance
--series-discharge-resistor
--max-current

To get the device information the following command could be used:

~/tenma$ ./battery-charger.py

Which should result (in the case of the TENMA 72-2540 device) in:

power supply found with id 'TENMA 72-2540 V2.1' (type 72-2540)

Normally no additional options are required to run this tool in Linux. When multiple USB devices are connected the tool might not find the (correct) PSU. In this case look for an tty USB device by disconnecting and reconnecting your PSU while checking which tty USB device dis- and re-appears:

$ ls /dev/ttyUSB*

Provide the correct device using the '-p' option:

~/tenma$ ./battery-charger.py -p /dev/ttyACM0

Or when the udev rules are installed:

~/tenma$ ./battery-charger.py -p /dev/tenma-psu

Provide a specific battery profile using the '-c' option:

~/tenma$ ./battery-charger.py -c lithium-250mAh-conf.py

When you get access denied errors running this tool, please refer to the INSTALL file and correct group permissions. If problems persist there is always the option to prepend the battery-charger.py command with the 'sudo' command (not advisable).

Once the device is connected using USB a virtual com port should be available. Check the 'devices' in the control panel and look for COM & LPT ports. The one you are looking for is called like "USB Serial (COMx)" or "USB CDC (COMx)". Try disconnecting and reconnecting your PSU while checking which device dis- and re-appears. In the examples below we assume the device was connected to COM3.

To get the device information the following command could be used:

C:\tenma> C:\Python310\python.exe battery-charger.py -p COM3

Which should result (in the case of the TENMA 72-2540 device) in:

power supply found with id 'TENMA 72-2540 V2.1' (type 72-2540)