To connect 8 12V batteries to create a 48V system, you should follow these steps:
(scroll down for diagrams)
- Arrange the batteries in two sets of four batteries each.
- In each set, connect the four batteries in series.
- Once you have two sets of four batteries connected in series, connect these sets in parallel.
Now you have a 48V system, as the batteries in series increase the voltage and the batteries in parallel increase the capacity.
Step-by-Step Connection Diagrams
Arrange the batteries in two sets of four
Separate the eight batteries and make two sets of four batteries each. Ensure the positive terminal and negative terminal are facing each other.
Connect the four batteries in series, and repeat for the two sets
If we connect batteries in series, we increase the voltage. Having four 12V batteries in series makes 48V. We repeat this for the second set.
Connect the two sets in parallel
Now we will connect these two sets in parallel. Connecting in parallel increases the capacity (Ah) of the battery. This means that we will have a 48V battery with 200Ah capacity.
Ensure that the main positive terminal of the battery comes from battery 1, not from battery 5. If you connect the main positive to battery 5, the lower series set will work harder, resulting in unequal charging and discharging of the battery. Therefore use battery 1 as the main positive and battery 8 as the main negative.
You need to fuse the main positive of the battery. To find out which fuse to use, read my guide on fusing.
If you connect batteries in series, ensure they are at the same state of charge! Always use safety goggles and insulated tools when working with batteries!
Conclusion
It’s easy to make a 48V battery out of 8 12V batteries. Follow this guide, and always wear safety glasses when working with batteries.
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hi
how do i link 4 x 12v 100a gel batteries to make 48v and also up the Ah? is it 4s2p?
You cannot increase the Ah if you connect 4 batteries in series. Series: adds up voltage, parallel, adds capacity (Ah).
I have 8 × 200ah × 12v I have 2sets of 48volts connected in parallel that means I have 400ah,which size of fuse I’m I supposed to use?
That depends on the load attached to your battery. I have made a guide on sizing fuses and wire here and here.
What side of breakers will I use to connect it with the inverter
Use a breaker on the positive side of the battery. I recommend having a fuse.
Hey there, great info on all your links. I’m wondering if this wiring diagram would work for 8 12v 100ah life po4 batteries to make 48v 200ah?
Yes, then the battery would become 48V 200Ah.
What is the disadvantages and advantages in connecting battery in series and parallel?
Read my article about that here.
Hi Nick, I currently have 8 x 12v 100Ah batteries set up for 48V. Does it matter if the additional 4 batteries are 12v 200Ah? Sorry Nick, I meant to add that I want to increase capacity to 12 batteries.
All batteries should have the same capacity if you make one battery bank of it. It’s still doable. Different capacities (Ah) is ok in parallel. However, these need to be completly seperate. You will make one 48V battery with your 8x 12V 100Ah batteries (4S2P). Then make another battery 48V 200Ah (4 12V 200Ah in series). Start the positive and negative leads from a busbar. Don’t use the studs of battery 1 to feed battery 2. Fuse the two battery banks seperate.