Configuring SLA Batteries
Battery packs are configured to suit their proper voltage (power) and amperage (runtime) by connecting its individual SLA batteries in different ways. A single battery holds a fixed voltage and amperage on its own, and when multiple batteries are combined in different ways to form a battery pack that generates the desired rating.
Increasing the voltage in a Series configuration is often used in golf carts, sweepers, scrubber, marine and other application. Parallel configuration is commonly used in engine cracking or deep cycle application where the same voltage is needed at a higher capacity or cold cranking amps. Below we have a few examples of configuring batteries in Series, Parallel and Series/Parallel.
Configuration 1 – Doubles Voltage, Amps Remain the Same
Series is the connection of two matching batteries used to double the voltage and keeping the amp-hour the same.
Configuration 2 - Double Voltage, Double Capacity
Series/Parallel is configured by connecting four matching batteries. It will double both the voltage and capacity.
Configuration 3 – Double Voltage, Capacity Increased by 3x’s
Series/Parallel - in this configuration you have connected 6 batteries to double the voltage and triple the capacity.
Configuration 4 – Quadruple Voltage, Camps remains the same
Series - connecting four matching batteries together to increase the voltage 4x. The amp-hour would remain the same.
Configuration 5 – Quadruple Voltage, Double Voltage
Series/Parallel - this is configured by connecting eight matched batteries to increase the voltage 4x and the amp-hour 2x.
Configuration 6 – Quadruple Voltage, Triple Capacity
Series/Parallel - Quadruple the voltage and triple the capacity by connecting 12 identical batteries.
Configuration 7 – (Parallel) Doubles Capacity, Voltage Remains the Same
Parallel - doubled the capacity by connecting 2 batteries matching batteries. This configuration is most commonly used in engine cranking or deep cycle applications where voltage needs to be unchanged.
Configuration 8 – Triple Capacity, Voltage Remains the Same
Parallel - triple the capacity while keep the voltage the same by connecting 3 matching batteries.
Rules About Battery Configurations
When configuring batteries in Series or Parallel; batteries should match Voltage, Capacity, State of Charge and Relative Age for safety and best performance.
Series - In Series configuration or series leg of series/parallel configuration, batteries should be as identical as possible.
Parallel - In Parallel configuration or parallel legs of series/parallel configuration, battery voltages MUST be identical, but battery capacity, state of charge, and relative age can vary moderately from one parallel leg to another.
Connection Engine Cranking Batteries the CCA (cold cranking amps) are multiplied by the number of parallel connections. This is also true with amp-hour capacity in deep cycle application.
IMPORTANT NOTICE: When connecting batteries together and dealing with positive/negative currents you must remember to follow these guidelines:
- Never connect cells in parallel and/or series that are not designed for that purpose. A cell mismatch may cause overcharge and venting with flame.
- Never charge or discharge the battery without connecting a working protection circuit. Each cell must be monitored individually and the current disconnected if an anomaly occurs.
- Always attach a temperature sensor when charging and discharging the battery. The temperature sensor must disconnect the current on excess temperature.
- Only connect cells that are matched and have the identical state-of-charge.
- Pay special attention when using an unknown brand. Not all brands contain intrinsic safety features that protect the cell when stressed.
- During experiments, place the test battery into a well-ventilated fireproof container.
- Never leave the battery unattended while under charge or discharge.
- Do not charge a battery that has physical damage.