4S1P Li-ion Battery Pack & Smart BMS Simulator
Cell chemistry
Parallel cells per group (M)
Series interconnect: Nickel-plated copper 0.30 × 12 mmrated 38 A
V = N × 3.7 V · Ah = M × 2.5 Ah · Wh = V × Ah. Each series link carries the full pack current, so strip and leads are sized for the larger of the 1 × 20 A cell rating and the 35 A OCP threshold (chassis-wiring ampacity, short leads).
- 4S series string1/4
- Polarity
- Sense ribbon B−…B+disconnected
- Device on P+ / P−open
Click or drag pin → pin to run a lead
Electrical rules check
- Series string incomplete — longest chain links 1/4 cells. Join each cell's + to the next cell's −.
Cell monitoring matrix · 4S
Sensed via B−…B+ ribbon · cells carry ±2.5 % capacity and charge-efficiency spread, so ΔV drifts with use.
Protection triggers
| Trip | Threshold | Live | Delay | Opens | Status | Last response |
|---|---|---|---|---|---|---|
| OVP Over-voltage | > 4.25 V | — | 1000 ms | CHG-FET | ARMED | — |
| UVP Under-voltage | < 2.80 V | — | 1000 ms | DSG-FET | ARMED | — |
| OCP Over-current | > 35.0 A | 0.00 A | 8 ms | DSG-FET | ARMED | — |
| OTP Over-temp | ≥ 60 °C | 25.0 °C | 2000 ms | CHG + DSG | ARMED | — |
Trip event log
No trips yet. Push the load past OCP, charge into OVP or discharge into UVP.
Cell balancing
Bleeds any cell > 15 mV above the lowest, also under load or charge.
Each channel dumps V²/33 Ω ≈ 0.53 W as heat (R_th 55 K/W → +29 °C). Switch on the IR view to see the resistors glow.
No readings yet. Set a load or charger, place the DMM probes and press Record observation — each row is compared against the ECM prediction in the lab report.