How to Connect Two 12V Batteries in Series to Make 24V?
3 Answers
Use a wire to connect the positive terminal (red connector) of Battery A to the negative terminal (black connector) of Battery B. Then, connect the negative terminal (black connector) of Battery A with a wire; use another wire to connect the positive terminal (red connector) of Battery B. The negative terminal (black connector) of Battery A and the positive terminal (red connector) of Battery B will then provide 24V.
I remember the last time I repaired an old truck, I wired the batteries in series to boost the voltage to 24V—so exciting! Simply put, I connected the positive terminal of the first battery to the negative terminal of the second battery with a wire, then used the negative terminal of the first battery and the positive terminal of the second battery as the output, doubling the total voltage to 24V. I secured the connections with alligator clips to prevent loosening and verified the output voltage with a multimeter. This method works well for high-voltage equipment like truck starter motors—doubling the voltage while keeping the current capacity the same is safer. Avoid parallel connections, as they maintain 12V but drastically increase current, risking burnout. Before connecting, I wore insulated gloves and worked in a dry area to prevent short-circuit sparks. Key points: Use batteries of the same model and similar charge levels to avoid imbalance and damage during charging. Adding a fuse afterward adds extra safety.
As someone frequently involved in battery maintenance, I emphasize that series connection is all about safety precautions. The steps are: first, disconnect all power sources and ensure the work area is well-ventilated; connect the positive terminal of Battery A to the negative terminal of Battery B, then use the remaining two terminals to connect to the system. This operation increases the voltage to 24V while keeping the current value unchanged, making it suitable for marine motors. Always wear anti-electric gloves during connection, and insulate metal tools to prevent accidental short circuits that could lead to explosions—lead-acid batteries are particularly dangerous as they can release hydrogen gas. After completion, use a multimeter to test the output terminals to confirm 24V, ensuring correct connection and avoiding reverse polarity damage to equipment. Why 24V? It’s more efficient for high-power loads. A common mistake is loose terminals causing poor connections; I recommend beginners attempt this under professional supervision or refer to manuals. Related topic: Battery aging affects series performance, so regularly check for terminal corrosion.
