• Adding auto battery disconnect on completed charge

    David Brown • 12/21/2020 at 00:51 • 0 comments

    So to upgrade the charger to automatically disconnect the battery once charging is completed I plan to add a MOSFET into the output line that is enabled by the charging in progress indicator.

    In order to initiate charging a push button will allow a bypass to start the charging and to latch whilst charging is in progress.

    The main parts are the high current / high power MOSFET capable of running in DC mode for the required current and voltage [SUP85N10] and the 5V regulator capable of being run off the high voltage 54.6V output [ZXTR2005ZQ]

    The voltage of the indicator LED is only 2.23V so an additional transistor is needed to buffer the signal to drive the large MOSFET

  • Adjusting the S120 battery charger

    David Brown • 12/21/2020 at 00:41 • 0 comments

    I bought a S120 lithium battery charger that was setup for LIFePo batteries and needed to adjust the float voltage to standard lithium 54.6V and re-set the charge finished current level ~300mA.

    This charger has 3 pots to adjust the float (constant voltage) level, the charging current (constant current) and the current level at which charging is indicated as being complete.

    There is no automatic disconnect of the battery once charging is complete, so this charger cannot be left unattended during charging.