Denver BAS-24200M Manual De Instrucciones página 6

Charge the battery: Charge the battery before starting to use
the device. Connect the charger to a mains wall socket, and
then plug the jack into the charging base (wait for a moment until
an audio feedback notifies the charging starts) or put it directly
into the micro USB port. When charging has been completed, a
second audio feedback will be heard.
Attention: To preserve the functionality of the product and the
integrity of the warranty, were commend the use of the original
chargers. Please charge the battery indoors or in a dry and
favorable environment. It's normal for the battery to get slightly
warm during the charging process. The battery will reach its full
capacity only after several complete charging cycles.
ENG-5