SolarDesignTools provides free interactive online design tools for Electric Solar Power energy systems. This includes determining the required number of solar panels, how many batteries will be needed, calculating wire sizes, a solar radiation chart, example system pictorials, and more.
Try this example of an interactive electric Solar Power Simulator to see how Solar Energy systems work.

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Battery Bank Designer

Parallel Wiring
The example battery wiring on the right shows six 12 Volt batteries wired in parallel. When batteries are wired in parallel, the voltage of all the connected batteries is the same as the voltage of just 1 battery. But, the current (AmpHour capacity) adds and is 6 times as much as 1 battery.
Series Wiring
When batteries are wired in series as the left wiring example shows, the voltage adds and is 6 times the voltage of 1 battery. If you used 2 Volt batteries in this example you would have a total of 12 Volts. The current(AmpHour capacity), however, stays the same as the current(AmpHour capacity) of just 1 battery.
Combination Series/Parallel Wiring
You can also use a combination of series wiring and parallel wiring. In the second wiring example, the six 2 Volt batteries are wired in series and add up to 12 Volts. But the current/amps remains the same. By wiring 2 groups of 6 series connected batteries in parallel, you can double the current (AmpHour Capacity) and maintain the voltage at 12 Volts.
Summary
So, depending on the voltage of each battery and how you wire them together, any combination of Voltage and Current (amps) is possible. It's easy to remember the difference between series and parallel wiring.

In series the current (flow of electrons) can travel only 1 path. That is from one battery, through it, and then to the next and so on. The current remains the same but the voltage adds. A simple example of series wiring is a common flashlight.

In parallel, since all negative connections are together and all positive connections are together, the current can (and does) flow through multiples paths. The voltage remains the same but the current adds. An example of parallel wiring is jump starting a car battery with another car battery.

So, series wiring provides only 1 path, and parallel wiring provides multiple paths. To calculate the number of required batteries, use our System Sizing Tool. Also, the Example Wiring Diagrams will show where the batteries fit into the overall Solar Power System wiring.

    Series Battery Wiring
  • The Voltage adds.
  • The Current remains the same.
    Parallel Battery Wiring
  • The Current adds.
  • The Voltage remains the same.
    Series/Parallel Battery Wiring
  • The Current adds.
  • The Voltage adds.

Home / Overview Starting Guide System Sizing Tool Battery Designer Wire Size Calculator Tips & Strategies Terms & Definitions
Solar Panels Charge Controllers Storage Batteries Inverters/Generators Meters & Monitoring Solar Radiation Wiring Diagrams

DISCLAIMER : The information and suggestions on this website are generally proven and accepted standards and techniques. They are, however, not meant to supersede local zoning laws or the recommendations of a licensed electrician. Always read the instructions provided with your equipment and observe all safety precautions.