Customers often ask how we know that the battery life of Holosun sights is so long when they have only been on the market for a few years.   It comes down to simple math.


Any battery or more properly referred to as a cell in this case, has a capacity.  The capacity is measured in ampere-hours or Ah.  As an example, a AA size cell has a capacity of 2 to 3 ampere-hours.  This means that the cell can supply a current of 2 - 3 Amps for 1 hour.


A CR2032 Lithium cell, has an ideal capacity of 250 milli-ampere-hour (mAh).  A good quality CR2032 has a capacity 220 – 240 mAh.   The Energizer CR2032 cell supplied by with all Holosun sights distributed by in Canada, has a capacity of 240 mAh.

As an example, an HS403A sight operating at intensity level 7 uses 5.9 micro-amps (µA).   Using a 240 mAh cell, the battery life would be 40,600 hours.    (240 mAh / 0.0059 mA = 40,600 hours).   This assume continuous operation.  Many of the sights have an auto-off mode that effectively extends this life to the shelf life of the cell. has set up test equipment to confirm the factory specifications.  


The test equipment includes:

  • And Extech MN16A digital multi-meter with a micro-ampere range,
  • A custom built battery holder for a CR2032 with binding terminals,
  • A CR2032 cell with the electrolyte removed and test leads attached that can be inserted where the battery tray goes,  
  • and a variety of cables and probes.



HS403C at intesity level 6, showing a current draw of 5.4 µA.


Here is a table of actual readings from a selection of sights.   Please note that the accuracy of the meter is +/- 1.5% and that the length of the tes leads likely add to the current draw.  This is far from laboratory quality.


 battery test table


The solar mode tests were performed with a bright fluorescent lamp indoors.   


A few calculation examples:


HS503C on battery with the circle dot reticle enabled.   Intensity level  7.    240 / 0.0242 = 9,917 hours.

HS503C on battery with dot reticle.    Intensity level 7.  240 / 0.0156 = 15,384 hours.

HS503C on battery with circle dot reticle enabled.  Intensity level 12.  We call this thermonuclear.  You can see this in the sun.   240 / 2 = 120 hours

HS503C on solar with circle dot reticle.  Intensity level 7.   240 / 0.009 = 26,666 hours.


Intensity level 7 is actually quite bright.   Indoor shooting would be at an even lower setting.   As you can see, the battery life at a mid-level setting is years.  This is further enhanced by auto-shutoff settings.  By the nature of the electronics, as intensity increases, current draw increases more rapidly.  Even at higher intensity settings, battery life still exceeds the competition.