Nikon D300 User Manual page 312

A
Using AA Batteries
EN-EL4a or EN-EL4 rechargeable Li-ion batteries (available separately) or
EN-EL3e rechargeable Li-ion batteries are recommended for best
performance. Fewer pictures can be taken with AA batteries (pg. 417).
The capacity of AA batteries drops sharply at temperatures below 20 °C
(68 °F) and varies with make and storage conditions; in some cases,
batteries may cease to function before their expiry date. Some AA
batteries can not be used; due to their performance characteristics and
limited capacity, alkaline and nickel-manganese batteries should only be
used if no alternative is available and then only at warmer temperatures.
The camera shows the level of AA batteries as follows:
Control panel
L
I
H
(blinks)
Battery level for EN-EL3e, EN-EL4a, or EN-EL4 rechargeable Li-ion batteries
is displayed normally.
U
286
Viewfinder
—
d
Low battery. Ready fresh batteries.
d
Shutter release disabled. Change batteries.
(blinks)
Description
Batteries fully charged.