For beginners of DIY LiFePO4 battery packs, connecting LiFePO4 cell to the BMS for the first time seems like a difficult task.
In fact after you operate it once, you will find it so easy. Because in the end it is only your manual dexterity that is tested. When you get good at it, you can make this connection in minutes.
First let’s take a look at some of the most used BMSs today. here we will use the 16S 48V BMS as an example.
1, JBD 16S 48V BMS JBD-SP25S003
2, Daly 16S 48V BMS
You will find almost all BMS have similar design, they have B-, P- (JBD use C- to name it), balance wire, temperature sensor.
Before you install the BMS, you need to remove the balance wire from the BMS. Connect the balance wire and the battery cell first, and then plug the balance wire into the BMS after connecting the balance wire.
Reconfirm that all 16 battery cells are connected in series via the bus bar.
For easy description, we number the 16 battery cells as Cell1 – Cell16. Cell1 is the negative terminal of the battery pack and C16 is the positive terminal of the battery pack.
1, Connect the balance wires
Usually there is one more balancing wire than the number of cells, because there is a balancing wire to connect to the negative terminal of the last cell, Cell1 (the negative terminal of the battery pack), which is usually black (you can also easily find it through the BMS manual).
The balance wire next to the black wire is connected to the positive terminal of the last battery cell.
The next balance wire is connected to the positive terminal of each cell in order. Until the last balancing wire is connected to the positive terminal of the Cell16 (the positive terminal of the battery pack).
After connecting all the balance wires, you need to make sure that all the balance wires are properly connected to the plug. The voltage difference between each two adjacent balance wires on the plug port should be equal to the voltage of the cell, i.e. 3.xV.
2, Insert the balance wire plug into the BMS
After confirming that all balance wires are accurately connected to the corresponding cells, you can insert the balance wire plug into the balance wire slot of the BMS.
At this time, the BMS has started to work. For the smart BMS, you can use your phone to connect to the BMS via Bluetooth and see the status of each cell in the APP.
3, Connect BMS to battery pack
Connect the B- of the BMS to the negative terminal of the battery pack (the negative terminal of Cell1). This step needs to be done carefully to prevent sparks (insulated gloves and goggles are necessary).
Connect P- (JBD’s C- terminal) to the negative terminal of the load (or charger). It is a good idea to secure the BMS before connecting to the load to prevent movement of the BMS from causing the wire to fall out.
At this point the BMS installation is complete.
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