Wiring Your Batteries in Series to Increase Voltage
24-Volt Battery Bank Wiring
Two 12 volt 100 amp hour batteries wired in series result in a 24 volt 100 amp hour battery bank (two 6 volt batteries wired in series results in a 12-volt battery bank). When wired in series, the battery voltage doubles, but the amp hours stay the same as a single battery.
Amp hours are the capacity of a battery. A 200 amp hour battery will run twice as long as a 100 amp hour battery before you need to recharge.
You can also use the above wiring diagram for connecting two 6 volt batteries in series to achieve a 12-volt battery bank
Facts About Series Wiring Batteries
You do not lose any power by hooking up batteries in series. The benefit is that you can operate equipment that requires 24 volts, such as inverters, DC water heating elements, dump load heaters, etc.
Do not operate equipment that requires 12 volts with a 24 volt battery bank. Doing so will cause the equipment to overheat and may result in damage. If your solar panels are for 12 volt charging, you can connect them together in series to charge your 24 volt battery bank. To do this, just connect the panels together the same way you connected the batteries. Check with the solar panel manufacturer for more details if you plan on wiring a large number of panels together.
Cool batteries have a longer life span. Make sure to leave a half inch air space around all sides of your batteries to allow for airflow around them to keep them cool. You may also partially submerge batteries in water to keep them cool.