EOTech 553 - Manual (Page 21)

CAUTION - There is a 12 volt battery that is approximately the same size as the Type N
1.5 volt alkaline battery used in the M551. DO NOT USE 12 V batteries in the M551. They
will severely damage the sight.
Two AA size batteries power the M552. Two 123 size Lithium batteries power the SU-231/PEQ
(M553). A set of batteries comes with the sight. Lithium AA batteries offer longer life, particularly
at temperatures below freezing. For this reason Lithium AA batteries are recommended for cold
weather operations. However, it should be noted that the battery checking function, which is
based on the characteristics of alkaline batteries, does not operate properly when Lithium AA
batteries are used in the model M552 and may not indicate a low battery condition until very
little battery life is left. The battery checking function of the M553 is designed only for the
123 Lithium battery and will function as described in section 2.1.2.
Figure 3:
Proper battery
Installation
13