Uniden BC246T Owner's Manual page 31

Before installing batteries, set the switch in the battery
compartment to match the type of batteries you will use.
Select REG. ALK. BATT. for non-rechargeable battery
types and NI-MH. BATT. for rechargeable battery types.
See also "Using Rechargeable Batteries" on Page 32
when you use rechargeable batteries.
1. Remove the battery cover and set the battery switch.
2. Install 2 AA batteries, matching the polarity symbols
(+ -).
WARNING!
Set REG. ALK. BATT./NI-MH. BATT. to NI-MH. BATT.
for use only with rechargeable batteries.
Never attempt to recharge non-rechargeable batteries.
Non-rechargeable batteries can get hot and can even
burst if you try to recharge them.
Setting Up Your Scanner
31