B42 Model Label: 14INR22/71-4. The arrangement is fourteen series groups of four parallel cells: 56 cells of the 21700 class.
| Label rating | Value | Label rating | Value |
|---|---|---|---|
| Nominal voltage | 51.66 V | Rated capacity | 18.3 Ah |
| Maximum charge voltage | 58.8 V | Rated energy | 945.37 Wh |
| Maximum charge current | 9.2 A | Maximum discharge current | 36 A |
Our private utility CLI can :
- Unlock battery charge/discharge output through the B42 pack's normal CAN authentication.
- Display live battery telemetry
- Detailed cell voltage and temperature views
- Decoded protection flags
- Switch feedback and JSON logging.
We will release the CLI at some point in the future.
$ b42_pack.py --bluetooth 00:xx:xx:xx:xx:xx --detailed
B42 node 1 | 2026-10-09T14:55:05.655+00:00
Cached AFE feedback: CHARGE (CHG) DISABLED DISCHARGE (DSG) DISABLED
Identity: LSBTB420FM_xxxxxxxxxxxxx_ | [CAN interface redacted]
Firmware 0x00010190 build 0x0077_xx_ model 0x4234_xx_
Stack 47.280 V PACK 0.210 V
Current -0.010 A Power -0.47 W (+ charge / - discharge)
SOC 33.0 % SOH 95.0 % Cycles 70 cycles Discharge estimate n/a
Capacity: remaining 6.011 Ah / full 18.136 Ah / design 18.000 Ah
Gauge: SOC 14.0 % current 0.000 A
Cells (mV, logical numbering):
01: 3374 02: 3374 03: 3374 04: 3375 05: 3375 06: 3376 07: 3375
08: 3376 09: 3378 10: 3380 11: 3380 12: 3380 13: 3383 14: 3384
Min 3374 mV max 3384 mV spread 10 mV balancing cells none
Temperatures (°C; sensor 2 = gauge; other physical locations unverified):
1: 21.0 2: 22.0 3: 22.0 4: 22.0
5: 21.0 6: 21.0 7: 21.0 8: 21.0
Selected temperature 21.0 °C
Advertised charge: 58.80 V, 4.00 A
Dynamic positive-current limit 29.0 A discharge recommendation 33 (raw)
Mode/session counters: vehicle charge 0 mAh discharged 0 mAh
Fault summary no
Status: 54=0x0080 58=0x0000 5C=0x0000 60=0x0000 64=0x0008
Flags: presence absent, discharge auth missing
Decoded status flags (cached):
54: Presence ABSENT [bit 7] | Application SOC 20% OR ABOVE [bit 8] | Charger detection NOT DETECTED [bit 9]
Charge temperature inhibit clear [bit 10] | Discharge temperature inhibit clear [bit 11]
58: Overvoltage state clear [bit 0] | Undervoltage state clear [bit 1] | Idle inhibit clear [bit 15]
5C: CHARGE (CHG) DISABLED [bit 13] | DISCHARGE (DSG) DISABLED [bit 14] | Fault summary clear [bit 15]
60: Balancing cells none
64: Discharge authentication MISSING [bit 3] | Predischarge retry failure clear [bit 5]
Excessive PACK voltage clear [bit 11] | Precharge inactive [bit 12]$ b42_pack.py --bluetooth 00:xx:xx:xx:xx:xx --mode discharge --detailed
B42 node 1 | 2026-10-11T13:35:29.494+00:00
Cached AFE feedback: CHARGE (CHG) ENABLED DISCHARGE (DSG) ENABLED
Identity: LSBTB420FM_xxxxxxxxxxxxx_ | [CAN interface redacted]
Firmware 0x00010190 build 0x0077_xx_ model 0x4234_xx_
Stack 47.250 V PACK 47.240 V
Current -0.010 A Power -0.47 W (+ charge / - discharge)
SOC 14.0 % SOH 95.0 % Cycles 70 cycles Discharge estimate n/a
Capacity: remaining 2.528 Ah / full 18.252 Ah / design 18.000 Ah
Gauge: SOC 16.0 % current 0.000 A
Cells (mV, logical numbering):
01: 3371 02: 3371 03: 3370 04: 3372 05: 3372 06: 3373 07: 3373
08: 3374 09: 3375 10: 3376 11: 3378 12: 3377 13: 3380 14: 3381
Min 3370 mV max 3381 mV spread 11 mV balancing cells none
Temperatures (°C; sensor 2 = gauge; other physical locations unverified):
1: 22.0 2: 23.0 3: 22.0 4: 22.0
5: 22.0 6: 22.0 7: 22.0 8: 22.0
Selected temperature 22.0 °C
Advertised charge: 58.80 V, 4.00 A
Dynamic positive-current limit 29.0 A discharge recommendation 25 (raw)
Mode/session counters: vehicle charge 0 mAh discharged 0 mAh
Fault summary no
Status: 54=0x0100 58=0x0000 5C=0x6000 60=0x0000 64=0x0000
Flags: application SOC below 20%
Decoded status flags (cached):
54: Presence PRESENT [bit 7] | Application SOC BELOW 20% [bit 8] | Charger detection NOT DETECTED [bit 9]
Charge temperature inhibit clear [bit 10] | Discharge temperature inhibit clear [bit 11]
58: Overvoltage state clear [bit 0] | Undervoltage state clear [bit 1] | Idle inhibit clear [bit 15]
5C: CHARGE (CHG) ENABLED [bit 13] | DISCHARGE (DSG) ENABLED [bit 14] | Fault summary clear [bit 15]
60: Balancing cells none
64: Discharge authentication PRESENT [bit 3] | Predischarge retry failure clear [bit 5]
Excessive PACK voltage clear [bit 11] | Precharge inactive [bit 12]State Of Charge (SOC), State Of Health (SOH) and capacities are drawn directly from the B42 telemetry.
Connector face · Connector wiring
| Pin | Colour | Function |
|---|---|---|
| + | Red | Switched pack positive |
| − | Black | Pack negative |
| 1 | Yellow | ECU: pack-controlled pulsed signal |
| 2 | Green | CAN-H |
| 3 | Blue | CAN-L |
| 4 | White | DET: active-low wake/presence input |
PCB signal wires run top-to-bottom yellow, green, blue, white in the board image. ECU's driver circuitry, electrical limits and external receiver remain unresolved. DET asserts presence when pulled low.
PCB: LB42ST-A03 · Numbers identify components; dashed sections indicate proposed functions.
Open the image for full-resolution annotations.
| Map | Reference | Component / role |
|---|---|---|
| 1 | U300 | STM32G0B1RCT6 microcontroller; firmware and communications |
| 2 | U100 | TI BQ76952; monitoring, balancing and protection |
| 3 | U800 | TI BQ34Z100-family fuel gauge; revision unconfirmed |
| 4 | U400 | TI TCAN1042-family CAN transceiver with VIO |
| 5 | Q103 | NCE0110AK MOSFET; circuit role unresolved |
| 6 | F200 | Dexerials SFK-5045A, 45 A protection fuse |
| 7 | Q206? | NCEP029N10D power MOSFET; reference tentative |
Functional groupings and labelled SWD/I²C access are inferred from visible parts and routing. B1–B13 mark intermediate cell-stack connections; B− and B+ are the ends. Full wiring remains unverified.
Classic CAN · 250 kbit/s · Standard 11-bit identifiers
Periodic reports and on-demand reads expose :
- pack/cell voltages
- currents
- temperatures
- SOC/SOH
- design/full/remaining capacities
- cycles
- balancing
- protection flags
- charge/discharge feedback
- identity
- recorded voltage/current/temperature extrema (they do not establish a complete lifetime fault history)
Charging and discharge have separate qualifying conditions. For discharge authentication, the pack supplies a challenge; the controller calculates a reply using repeated arithmetic and bit mixing; the pack compares it with its expected answer. A match satisfies the authentication condition, with firmware protections still governing permission.
left = SEED
right = challenge
total = 0
repeat 32 rounds:
total = u32(total + STEP)
left = u32(left + (
u32((right << 4) + K0)
XOR u32((right >> 5) + K1)
XOR u32(total + right)
))
right = u32(right + (
u32((left << 4) + K2)
XOR u32((left >> 5) + K3)
XOR u32(total + left)
))
reply = u32(left + right)