Group 79 Automotive Batteries

3D rendering of the BCI (Battery Council International) Group 79 battery for cars and trucks.

Electrical Specifications:
12 Volts
800 Cold Cranking Amps (CCA)
140 Reserve Capacity Minutes
Left Positive Polarity

Mechanical Specifications:
Length: 12 1/8" (30.7 CM)
Width: 7 1/16" (17.9 CM)
Height: 7 7/16" (18.8 CM)
Body Style: Cutaway with Backwards Hat top
Terminals: Left Positive Side Post
Flanges: Face Sloped Foot


   We measure battery power with two numbers: Voltage and Capacity.  All 79 batteries provide 12 Volts and strong international standards have made sure that everyone agrees on what Voltage means and how to measure it.  Capacity, however, varies between manufacturers and brands.  To complicate matters further, we measure automotive battery capacity in a variety of ways.
   Capacity measures the number of electrons a battery can provide.  In general, we measure battery capacity in amp hours, or watt hours, however, in automotive applications, we care more about how much electrical power a battery can supply instantaneously to start the engine.  We measure this instantaneous power in CA, Cranking Amps, and CCA, Cold Cranking Amps.  Batteries store chemical energy and release it through temperature sensitive chemical reactions.  In cold climates, we only care about CCA, because they report how much instantaneous power the battery can supply at zero degrees Fahrenheit.  When new, Group 79 batteries must provide a minimum of 800 CCA to meet standards but many manufacturers exceed the requirements.
   Modern vehicles increasingly rely on their batteries to power peripheral electrical features like sound and entertainment systems, navigation computers, USB ports, light bars, winches, inverters, communications devices, and countless other specialized electrical equipment.  We call these features deep cycle applications because they draw smaller amounts of power over longer time periods.  We measure deep cycle capacity in Amp Hours or Reserve Capacity Minutes.  To meet specifications, new group 79 batteries must provide at least 140 Reserve Capacity Minutes but many batteries exceed these capacity requirements.


   Group 79 batteries have Cutaway body shapes with overall dimensions of: 12 1/8" X 7 1/16" X 7 7/16" or 30.7 CM X 17.9 CM X 18.8 CM.  The 7 1/16" (17.9 CM) length includes the flanges.  The 7 7/16" (18.8 CM) height includes the Backwards Hat top and any protruding acid caps, but not any raised lifting straps or handles.
   Vehicles can fasten group 79 batteries with top mounted hold down straps/bars or by gripping any of its Face Sloped Foot flanges, and connect electrically via leads fit for Left Positive Side Post terminals.

Example Battery Images:

More example images coming soon.  

Where to Buy: