battery

+- [[Tech-DAT]] - [[display-dat]] - [[network-dat]] - [[usb-dat]] - [[interactive-dat]]

+

+- [[power-dat]] - [[battery-dat]]

+## basic active charger

+

+### 2S version

+

+

+

+The diagram below shows the module discharge. The battery is a 2-series configuration, and the connected batteries must support a 20A discharge current. This can be achieved by connecting batteries in parallel or by purchasing batteries with a higher discharge current.

+

+For example, if the battery is 2000mAh with a 10C discharge rate, then only 2 series and 2 parallel (2S2P) are needed, which can provide a discharge current of 40A.

+

+For stable discharge, 2 series and 4 parallel (2S4P) are required, and attention should be paid to heat dissipation, as the battery power will drop quickly during discharge.

+

+

+

+- To successfully start an electric drill, you need two 10C-20C power batteries, or four 5C-10C power batteries (recommended battery models: Sony VTC4S, VTC4A, VTC5, VTC6). For the 0V and 8.4V connection wires, use copper wires of at least 2 square millimeters (do not use strips).

+- When welding the battery for the first time, you need to charge it first to get output. Strictly follow the diagram to connect 0V, 4.2V, and 8.4V. When welding wires, do not touch any components on the board, and do not intentionally short-circuit.

+- When welding the battery for the first time or while charging, as long as any single cell exceeds 4.2V, the "430" resistor will heat up to discharge (discharge stops when it drops to about 4.19V). If the "430" resistor becomes very hot (too hot to touch), please check if the wiring is incorrect.

+

+#### 故障处理：

+

+| Fault Phenomenon | Fault Check & Cause |

+|--------------------------|------------------------------------------------------------------------------------------------------|

+| Cannot charge | Measure the voltage of 3 battery groups. If any group exceeds about 4.25V, the protection board triggers overcharge protection. |

+| Cannot discharge | Measure the voltage of 4 battery groups. If any group drops below about 2.5V, the protection board triggers over-discharge protection. |

+| Charging/discharging fails | OV, 4.2V, 8.4V wires are connected incorrectly. |

+| Overcharge/over-discharge fails | OV, 4.2V, 8.4V wires are connected incorrectly. |

+| Discharge protection | Check if the battery pack has sufficient discharge capability. |

+| Cold solder joint | Check if the load's starting current exceeds the protection board's overcurrent protection current. |

+| Solder bridge | One pin of a component is not connected to the PCB pad, or two or more pins are shorted together. |

+| ESD breakdown A | When powered off, measure MOSFET G, D, S pins. If the forward and reverse resistance between any two pins is 0Ω, it is broken down. |

+| ESD breakdown B | Remove the MOSFET and measure resistance between G-D and G-S. If resistance exists, it is broken down. Normally, resistance should be

+

+

+### 3S version

+

+

+

+note

+

+1. Strictly follow the diagram to connect 0V, 4.2V, 8.4V, and 12.6V. Be careful to check for short circuits.

+2. When connecting 3 battery groups in series, make sure each group has the same voltage. If not, fully charge each group separately before connecting them in series. During discharge testing, the group whose voltage drops quickly is the bad battery—replace it with a good one.

+3. Never mix good and bad batteries together, and do not mix new and old batteries.

+4. To successfully start an electric drill, you need three 15C-20C power batteries, or six 10C-15C power batteries (ordinary 18650 batteries cannot start an electric drill!!!).

+5. For loads with brushed motors, you must connect a non-polarized capacitor (rated voltage above 25V, capacity 10uF-100uF) in parallel at the motor's positive and negative terminals to prevent reverse voltage spikes from the motor from interfering with the protection board or

+

+

+

+- [[BMS-dat]] - [[active-BMS-dat]] - [[passive-BMS-dat]]

+

+- [[battery-rechargerable-dat]] - [[lead-acid-battery-dat]] - [[LFP-dat]]

+

+- [[li-battery-dat]] - [[li-battery-app-dat]]

+## unbalance Series and Parallel

+You have a battery configuration: **3P + 6P + 6P in series**.

+- **3P group** = 3 cells in parallel

+- **6P groups** = 6 cells in parallel

+- **Series connection** → pack is 3S

+

+Even though some groups have more cells, the **smallest parallel group (3P)** limits the total usable capacity.

+

+---

+

+### 1. Discharge Behavior

+- Current is **the same through all series groups**.

+- Example: load draws 9A total:

+ - 3P group → 9A ÷ 3 = 3A per cell (high stress)

+ - 6P groups → 9A ÷ 6 = 1.5A per cell (lighter load)

+- ✅ 3P cells drain faster.

+- ❌ Pack is considered “empty” when 3P group is fully discharged, even if 6P groups still have charge.

+

+---

+

+### 2. Charge Behavior

+- Charger applies current evenly through series groups.

+- Example: 9A charging current:

+ - 3P group → 9A ÷ 3 = 3A per cell

+ - 6P groups → 9A ÷ 6 = 1.5A per cell

+- ✅ 3P group reaches full voltage first.

+- ❌ Charger stops when 3P group is full → extra cells in 6P groups aren’t fully used.

+

+---

+

+### 3. Key Effects

+1. **Capacity wasted**: Extra cells in larger parallel groups are underutilized.

+2. **Unbalanced stress**: Smaller parallel group wears out faster.

+3. **Reduced lifespan**: Smallest group limits whole pack life and capacity.

+

+---

+

+### 4. Best Practice

+- Ensure **all parallel groups in series have the same number of cells**.

+- Example: redesign as **3S6P** → full 18Ah usable capacity instead of being limited to 9Ah.

+

+---

+

+### ✅ **Summary**:

+In series packs, **the smallest parallel group determines the usable capacity**. Extra cells in larger groups are underused, and the smaller group experiences higher current stress, reducing overall pack efficiency and lifespan.

+- [[battery-protection-dat]] - [[BMS-dat]]

+power tool battery == 3S=3P/6P/6P == 15 batteries

+

+

+

+- [[battery-pack-dat]]

+

+3S10P == 30 batteries == 12V 30000 mAH

+

+3S5P == 15 batteries == 12V 15000 mAH