Configuration

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Factory configuration

For safety reasons, every Skycharge system comes with a factory configuration that makes the system output low voltage and low current. You must configure the system based on your needs.

Log in to the charge source

From a computer connected to the same local network, you must find the TCP/IP address of the charging station. By default, the charging station is easily discoverable by mDNS service: the default domain name is skydevice.local, thus the SSH connection to the system can be established as the following:

# ssh [email protected]

For the security reasons, password authentication is disabled on the system SSH server. The only way to access is the public key authentication. The private key for your system access can be downloaded here.

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Accessing the Skycharge system

More detailed information about how to access the Skycharge system can be found in the relevant SDK documentation section: Connect to your Skycharge system

Charge source configuration

The charge source can be persistently configured through its configuration file /etc/skycharge.conf
When you update the configuration file the changes won't become effective until skycharged is restarted. To manually restart skycharged you can invoke the following command:

systemctl restart skycharged

Charge source output voltage and current

You can set the desired output DC voltage and current by editing the following configuration parameters.

sink-batt-capacity-mah = <integer>

Specifies battery capacity in mA hours. The default value is 5000 mAh.

sink-batt-max-voltage-mv = <integer>

Specifies the voltage in mV which will be used for charging. For example if your battery is 6S, then the correct value can be 25200 (4.2 x 6).

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Expected voltage drop

Due to the voltage drop across the wires, you may want to slightly increase the voltage.

sink-batt-min-voltage-mv = <integer>

Specifies the minimum voltage in mV of the battery. If the battery is damaged, not connected or fully depleted so that battery voltage goes below the "sink-batt-min-voltage-mv" value, the charging won't start. See also the "mux-hw2-ignore-low-batt-voltage" configuration setting. For example if your battery is a 6S Li-Po, the correct value can be 18000 (3 x 6), where 3v is the minimum possible value of the Li-Po cell.

sink-charging-max-current-ma = <integer>

Specifies the maximum current in mA which will be used for charging.

sink-precharge-current-ma =  <integer>

Specifies the current value in mA which will be used for the precharging.

sink-precharge-secs = <integer>

Specifies the pre-charge value in seconds. After the charging has begun the current will start with the "sink-precharge-current-coef" / 100 x "sink-charging-max-current-ma" value and will be ramp up to the "sink-charging-max-current-ma". Current rumps up for "sink-precharge-sec" of seconds. The default value is 30 seconds.

Charge source timeouts

You can modify the main charging behaviors by editing the following configuration parameters.

sink-cutoff-min-current-ma = <integer>

Specifies the current cutoff threshold in mA. When charging current drops below this value, charging will be stopped. The default value is 1000mA.

mux-hw2-repeat-charge-after-mins = <integer>

When the powered on drone/mobile robot is connected to the source board for an extended period of time, the battery may be depleted. This parameter defines the interval in minutes when charging should be restarted. The default value is 10 minutes.

sink-precharge-delay-secs = <integer>

Specifies the delay in seconds after which the MUX board will start pre-charging. The default value is 0 second.

sink-total-charge-secs = <integer>

Sets the maximum number of seconds per charge cycle. If the current does not fall to the value of sink-charging-min-current-ma, then after this timeout, the charging cycle will end.

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Restarting the Skycharge daemon

When you update the configuration file, the changes won't become effective until skycharged is restarted. To manually restart skycharged you can invoke the command below.

systemctl restart skycharged

Charging curve with parameters