Canon EOS 1 Instructions Manual page 10

be
D
I
....
. ...
-Three bars--:- Battery power sufficient
be
D
I
-Two bars- Have a spare handy
10
be
D
I
,1..--
-.-._-
-One bar (blinking)- Replace battery
be
D
I
-be
(no bar)- Replace battery
-Blinking
be - '
Replace battery if old;
reload if new.
See p. 63.