Battery wiring series vs. parallel

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For those confused when it comes to wiring two or more batteries.....

Battery Bank Wiring

12 volts versus 24 volts


Most remote power systems are wired for 12 volts. Some larger systems are wired for 24 volts. It's a delicate call to make this decision in most cases. Even larger voltages are used in some huge systems. The main advantage of 24 volt systems over 12 volts is that wire size is cut in half throughout the system. Besides affecting battery bank wires, this includes solar panel, wind generator and hydro plant wiring, too--if you have hundreds of feet of wire, this cost can add up quickly. The disadvantages of using 24 volts are that 1) you'll need an expensive, power-wasting transformer to run 12 volt lights and appliances, and 2) if you want to buy a cheap, Chinese inverter, they are only available in 12 volt versions. More expensive inverters are available in different voltages.
Series and Parallel Battery WiringLead-acid batteries always have 2 volt cells wired in series to give the desired voltage. Some batteries have 3 2 volt cells in the case, already wired together for 6 volts. Most battery banks use a combination of series and parallel wiring.Series wiring increases voltage but NOT amp/hour capacity.Parallel wiring increases capacity but NOT voltage.
Series Wiring Example
Parallel Wiring Example