Parallel circuits have been around since their invention in the 1800s, but how does this pertain to batteries? You've probably heard of parallel or series connections when it comes to batteries, but what does this really mean? Today we will be tackling parallel configurations for our Powertex LiFePO4 Lithium Iron Phosphate batteries.
Parallel connections for batteries means, connecting anywhere from two to four batteries of like voltage and amp hour to increase the total capacity. For example, two 12V 100Ah batteries connected in parallel would net 200Ah of total capacity. Four of the same 12V 100ah would net a total of 400Ah of capacity. This is very useful for those with solar arrays that require storage of that energy but do not have the ability or space to support very large capacity batteries.
We will go over what materials are needed and the steps to safely connect four batteries in parallel.
Preparation Materials
- Creating your own wires:
- OT connectors - 10 pieces
- Keep in mind the current being used for these batteries. For example, on 100Ah batteries, connectors must be rated for at least 100A. On 12Ah batteries, connectors must be rated for at least 12A.
- Heat Shrink Tube - 10 pieces of at least 1.5"
- Wiring that is rated for at least 100A.
- Length depends on customer's needs.
- Powertex LiFePO4 Batteries PTL12100 12V 100Ah - 4 batteries
- Buying pre-made wires
- #2 AWG wire with OT connectors - 10 pieces
- #2 AWG wire is used as long as each wire is less than 10 feet.
- Powertex LiFePO4 Batteries PTL12100 12V 100Ah - 4 batteries
Creating Wires
a - Weld OT connectors and wires tightly.
b - Cover the connection part between OT connector and wires with the heat shrink tube.
Connecting Batteries
Connect batteries according to the images with the finished wires from the previous step. Make sure the wire coming out of battery 1 is from the positive terminal and the wire coming out of battery 4 is from the negative terminal.
Review
- Must make sure all 4 batteries are of same voltage and capacity.
- Fully charge each battery before connecting in parallel, voltage difference should be no more than 0.2V
- DO NOT reverse connect the positive and negative terminals or it could damage batteries, machine or even person.
- Wires must have a minimum of 100A rating.
- Charging should be at no more than 14.6V.
- Make sure all connections remain tight and do no loosen, connectors are protected from corrosion and wear. Connection impedance <0.1mΩ.
- Cannot connect in both series and parallel within same configuration or else it will spark / short circuit.
- Make sure capacity stays within 50% - 60% when storing. Fully charge every 3-6 months.
NOTE - Powertex Batteries only support 4 units in series connection or parallel connection. It is NOT allowed to do both series and parallel in same configuration.
CAUTION - Severe damage like sparking, short circuit can happen if person assembling or maintaining is not professional.
