Repository navigation
Hardware info
Andrej Tobola edited this page Aug 14, 2026
·
19 revisions
Below is the hardware architecture and component breakdown for the Dyson V10 BMS board.
| Function | Part / Identifier | Specification & Details | Datasheet |
|---|---|---|---|
| Microcontroller | Atmel ATSAMD20E15A-U | ARM Cortex-M0+ MCU | Datasheet |
| BMS IC | TI BQ7693003 | Battery Monitor & Protector (Requires CRC byte when writing registers) | Datasheet |
| Low-Side MOSFET | Nexperia PSMN1R0-40YLD | N-Channel 40V, 1.1 mΩ, 280A Logic Level | Datasheet |
| Current Shunt | 0.001 Ω (R12 / R001) |
Measures current consumption & feeds Coulomb counter | — |
| Thermistors |
RT1, RT2
|
Dual thermistors monitoring pack temperature | — |
| Battery Cells | 18650 Li-ion | 7S1P Configuration (7 cells in series). Various OEM suppliers (e.g., Molicel P26A rated at 30A continuous, 2.5V min). | — |
The pack uses a clever ultra-low-power management setup:
-
[Trigger Pulled] or [Charger Plugged]
$\rightarrow$ [BQ7693 Wakes]$\rightarrow$ [Brings up 3.3V Rail]$\rightarrow$ [MCU Powers On]
- Ship Mode (Sleep): The MCU puts the BQ7693 BMS IC into SHIP mode (ultra-low power consumption).
- 3.3V Rail Shutdown: Entering SHIP mode cuts off the 3.3V regulator rail, completely powering down the microcontroller to save battery life.
-
Wake-up Trigger: The BQ7693 BMS is woken up either by:
- Connecting a powered charger (+V detected on the charge connector).
- Pulling the vacuum trigger.
- Boot Sequence: Once woken, the BMS restores the 3.3V rail, which boots up the SAMD20 MCU instantly.
- Interface: Bidirectional USART serial link running at 115,200 baud.
- Physical Connection: Connected via the two additional signal pins inside the battery connector.
Note
Stock vs. Custom Firmware Behavior:
- Stock Firmware: Requires active bidirectional communication with a Dyson vacuum. If comms are not established within a few hundred milliseconds, the stock pack disables power output.
- This Firmware: Comms requirement is removed. The battery can be used as a standalone power supply for non-Dyson projects.
Warning
While cell balancing is technically possible on the BQ7693, it is extremely limited and disabled by default in stock firmware (CELLBAL registers set to 0x00).
- No External Balancing Circuitry: Balancing is handled strictly internally by the BQ7693 IC.
- Low Current: Limited to ~5 mA balancing current per cell (further restricted by 1 kΩ inline sense resistors).
- Adjacent Cell Restriction: The BQ7693 cannot balance adjacent cells simultaneously.
- Thermal Constraints: Package heat dissipation capacity on the BQ7693 is minimal during balancing.
Attempting to rebalance a severely imbalanced pack via internal balancing could take days or weeks.