Not all batteries are made equal.  Have you ever wondered why there are different battery sizes and ratings? Did you know every battery type serves a specific functionality?

The two main battery types are stationary batteries and “starting” batteries. It is very important that you find the correct battery for your particular application, as the wrong choice can affect both the battery’s efficiency as well as its lifespan.

Stationary Battery vs. Engine Start Battery

Stationary Batteries are meant to provide a continuous current of the same intensity for a prolonged time span.

Starting Batteries are just the opposite.  They are designed with thin plates so they can provide quick bursts of energy, such as a backup generator or car would need while starting.

STATIONARY BATTERIES


For a Stationary Battery to provide a continuous current of the same intensity for a prolonged time span, they are designed with thick internal plates that slows down the process delivering amperes to the load.  Stationary batteries are typically rated in ampere-hours. 

An ampere-hour represents the amount of electricity when a current of 1 Ampere passes for 1 hour.  The ampere-hour capacity varies with the rate at which the battery is discharged; the slower the discharge, the greater the amount of electricity that the battery will deliver.  A typical rate for ampere-hour capacity is the amount of electricity that a battery will deliver during 20 hours before the voltage falls to 10.50V. For example, a 60Ah battery will deliver a current of 3A for 20 hours.

STARTING BATTERIES


Starting Batteries are designed with thin plates so they can provide quick bursts of energy, such as a backup generator or car would need while starting. This only discharges the battery by about 1-3%, which is then topped off typically by an alternator. This is typically known as the battery cranking amps.

Cranking amps are the numbers of amperes a lead-acid battery at 32 degrees F (0 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery).

SUMMARY

To recap, stationary batteries provide a lower but longer duration amount of energy, but cannot deliver as many peak cranking amps.  Starting batteries are made to provide high power for higher amps, more frequent short draws, and limited long term discharge.