Batteries in series or parallel increase total available energy, measured in watt hours. But they do this in different ways, and with different results. Read on to find out how to connect your batteries in series vs. parallel, and discover which method is right for you.
Connecting batteries in series increases the amount of voltage. It doesn’t increase the capacity. For example, if you connect two 12V 30Ah batteries in series, you get a combined voltage of 24V. The capacity, 30 amp hours (Ah), stays the same.
Before you connect batteries in series, make sure they have the same voltage and capacity rating. Different batteries in series is dangerous, and shorten the whole battery’s life. You can charge several batteries in series. Just make sure you use a charger that matches the total combined voltage of all your batteries.
Connecting in series increases voltage, but wiring in parallel increases battery capacity. The total voltage doesn’t change.
That means two 12V 30Ah batteries in parallel and you will get a total capacity of 60 amp hours battery. Voltage stays at 12 volts.
Like wiring batteries in series, all batteries in parallel must have the same voltage and capacity.
Batteries in Series vs. Parallel: Which is better?
Let’s take a look at the advantages and disadvantages of each method.
Batteries in Series: Advantages and Disadvantages
Putting batteries in series is usually the better choice for large applications that need high voltage. (Say, more than 3000 watts, for example). Higher voltage means a lower system current, so you can use thinner wiring. There will also be less voltage drop.
There’s one main disadvantage of connecting batteries in series vs. parallel. When you do this, all your applications have to function at the higher voltage. For example, if you connect two 12V batteries in series, you’ll end up with 24V. You won’t be able to power any 12V appliances unless you use a converter.
Batteries in Parallel: Advantages and Disadvantages
What’s the principal advantage of wiring batteries in parallel vs. series? Voltage stays the same, but you can run your applications longer because you’ve increased the capacity. Also, if there’s a problem with one battery, it won’t affect the others. The working batteries will continue to power your appliances.
As far as disadvantages, placing batteries in parallel can make them take longer to charge. Also, the lower voltage means higher current draw and more voltage drop. It may be difficult to power large applications, and you’ll need thicker cables.