How to Put Batteries in a Series Two 12V

You can make two 24-volt batteries with four 12-volt batteries

If you need to make a 24-volt battery and only have two 12-volt batteries, you can connect the two batteries together to make one 24-volt battery. The two 12-volt batteries are connected end-to-end in what is known as a series battery connection. You will find series connections of batteries in many electronic devices like your everyday flashlight, you boom box and portable radio. These electronic devices, in addition to a series battery connection to double the battery voltage, also use a parallel battery connection to double the electrical current.

Things You'll Need

• 2 12-volt batteries
• Battery connectors
• Voltmeter

Instructions

1. Connect the positive terminal of the voltmeter to the positive terminal of the first battery. Connect the negative terminal of the voltmeter to the negative terminal of the first battery. Write down the voltage on the voltmeter's display. Do not use the battery if the voltmeter measures less than 11.8 volts. Repeat the procedure for the second battery. Continue until you find two batteries that meet the minimum 11.8 volt specification.

2. Connect the positive terminal of the first battery to the negative terminal of the second battery. Connect the positive terminal of the voltmeter to the positive terminal of the second battery. Connect the negative terminal of the voltmeter to the negative terminal of the first battery. Connect the positive terminal of the voltmeter to the positive terminal of the second battery. Connect the negative terminal of the voltmeter to the negative terminal of the first battery.

3. Write down the voltage on the voltmeter display. Call this voltage "the measured battery voltage of two 12 volt batteries connected in series." Add the recorded voltage of the first battery to the recorded voltage of the second battery. Write down this result and call the result "the calculated value of two 12 volt batteries connected in series." Recheck your connection if the measured voltage value is not the same or very close to the calculated voltage value.

Tips & Warnings

• Although you obtain twice the voltage when two batteries are placed in series, the amount of current is not double but limited to the amount of current one battery is specified for. Each battery in a series arrangement must supply the total current required by the load it must supply current to -- such as a resistor, a motor or another electronic circuit.

• Improper use of electronic equipment and components can result in fire, serious injury or death. Always work under the supervision of a safety certified electronic technician or electronic engineer. Obtain an electronic safety certificate before you work with electronic equipment and components.

References

• Yandina: How to Get 24 Volts for a Bow Thruster from a 12 Volt System
• Battery Tender: Connecting Batteries & Chargers
• Battery University: Serial and Parallel Battery Configurations
• Gizmology: Notes on Batteries