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Aux Battery size in Monitor


since the auxiliary lithium battery 18650 is not coming with the monitor, I am looking for the right one to buy here in Germany.

Will this one fit the monitor?
It has an own charge electronic and needs an CCCV charge modus.


Hello Jens,

The battery from the link is 69.5 mm long.  It is longer than the standard 18650 battery.

The maximum battery length that will fit in the battery holder is 68 mm.

The Monitor takes care of the charge and protection of the backup battery by limiting the charge current / voltage and by shutting down the Monitor if the battery voltage is too low.  So the electronics board (PCB) is not needed.  

Here are the backup battery specifications (from the manual):

  • type: Li-ion 18650
  • size: 18.5 mm diameter x 65 to 68 mm long
  • nominal / charge voltage: 3.7V / 4.2V
  • capacity: >= 3000 mAh