Juniper Allegro CE Owner's Manual page 36

The chart below describes the Allegro battery charging behavior at
different temperatures.
Temp. Range Temp. Range
Degrees C
Recommended 10° to 20°
Charge Range
Acceptable 0° to 30°
Charge Range
Too Cold < 0°
Range
Too Hot > 30°
Range
Try to charge the batteries within the recommended temperature
range. If you need to charge the batteries in temperatures exceeding
this range, you should purchase an extra battery and keep it charged
for the most efficient operation of the Allegro.
Power Connector
A dedicated standard external DC power input connector is located
on the top of the Allegro. The connector is 5.5 x 2.1 mm, 10 to 20 V DC.
The AC power adapter and optional vehicle power adapter are
inserted into this connector.
Charging Accessories for NiMH Battery Packs
There are several charging options available for the Allegro. The most
common is the AC power adapter that is shipped with your Allegro.
The USB/Power Dock, vehicle power adapter, and external battery
charger are all optional ways of charging the Allegro and can be
purchased seperately.
❏ AC Power Adapter: Using the AC power adapter, the battery pack
is recharged without removing it from the Allegro.
Please note that you must use the adapter included with the
Allegro or one that is capable of supplying adequate current (12 V
at 1 Amp). Otherwise, the battery pack could be damaged.
Page 2-24 Hardware Features
Degrees F Charging Behavior
50° to 68° Most efficient; batteries charge
within three hours.
32° to 86° Batteries are charged within four
hours.
< 32° The batteries must reach 0° C (14°
F) before they begin to charge.
> 86° Battery charge cycle is complete in
four to five hours. If the batteries
become too warm, they may only
reach a 90 to 95% charge capacity.
< Power Connector