Things You'll Need
Two 12-volt batteries
Three battery cables
While you can temporarily increase a 12-volt battery to 24 volts by storing a charge and then releasing it, the effect is shortlived; once the charge is delivered, the voltage returns to 12. The best way to make a 24-volt battery is to wire two 12-volt batteries using circuitry known as series. There are two main circuits in use: series and parallel. Wiring two 12-volt batteries in series combines the voltage from each unit to double its output, thereby allowing the electric current to flow evenly through every component in the circuit. Wiring two 12-volt batteries in parallel provides longer battery life, but the output will remain 12 volts. Making a 24-volt battery from two 12-volt batteries is moderately simple if you follow a few guidelines.
Connect one battery cable to the positive (+) terminal of one of your 12-volt batteries.
Connect the other end to the negative terminal (-) of the second 12-volt battery. You now have two batteries connected in series. One battery will have an unused negative (-) terminal and the other a used positive (+) terminal.
Use a battery cable to connect to the unused negative (-) terminal and another to connect to the unused positive (+) terminal. Ensure that you do not allow the negative and positive cables to touch each other as your combined voltage is now 24 volts.
Connect the other end of the negative (-) cable to the negative terminal on your power unit. When you are ready for your power unit to operate, connect the remaining cable to the positive (+) terminal of your power unit. Your batteries will produce an output of 24 volts to enable you to run your 24-volt power unit.
Fit a switch or circuit breaker between the cable linking the positive battery terminal to the positive terminal of the power unit. This will enable you to switch the power on and off as required.
Ensure that your power unit is set up to run on at least 24 volts. Otherwise, you may damage it.
Stephen Benham has been writing since 1999. His current articles appear on various websites. Benham has worked as an insurance research writer for Axco Services, producing reports in many countries. He has been an underwriting member at Lloyd's of London and a director of three companies. Benham has a diploma in business studies from South Essex College, U.K.