The 3D shape is our own approximate drawing, sized from the teardown photos, not the maker's CAD. Parts sit roughly where they were found.
BrainAllwinner MR5274 GB Rayson LPDDR4X, 32 GB Rayson eMMC
Mobile dataQuectel EC25 4GQualcomm MDM9207 inside
Wi-Fi + BluetoothEA6621QF moduleon the computer board
Motors + safetyGigaDevice GD32F427Arm Cortex-M4 on the driver board
Long-range radioSi4463-type chipsub-GHz, in its own shielded can
BatteryNBCF2213A pack21.6 V · 12,800 mAh · 276.5 Wh
Board names as printed on the boards; sizes are approximate.
Chameleon_cpuComputer board, about 150 × 75 mmThe Linux side: processor, memory, storage, power chip, the 4G module, Wi-Fi and Bluetooth. "Chameleon" is printed on both boards and looks like Segway's internal name for this mower.
Chameleon_DRIVER_HPDriver board, about 240 × 170 mmThe muscle and the safety net: the GD32 microcontroller, three banks of power transistors, the battery connector, a buzzer and the long-range radio in a shielded can.
The brain: Allwinner MR527 Read
The computer board carries an Allwinner MR527 under a shielding frame, with a Rayson RS1G32LX4D4BNR-53BT memory chip beside it and a Rayson RS70B32G4 storage chip below. The memory part number decodes to 1G×32, which is 4 GB of LPDDR4X; the storage part is a 32 GB eMMC. A power-management chip marked X-Powers AXP717B feeds them.
Why it is there. This is where mapping, the camera-based obstacle detection and the app connection run. The MR527 is the robot-series sibling of Allwinner's 8-core T527: eight Arm Cortex-A55 cores.
- Memory and storage sizes are decoded from the part numbers, not from a spec sheet.
4G: Quectel EC25 module Read
A Quectel EC25 LTE module is soldered to the computer board (the label reads EC25-AF…). With its lid off, the inside is readable: a Qualcomm MDM9207 modem, an ESMT FM6BD1G1GMB memory chip and a Qorvo QM56020 radio front end.
Why it is there. The X3 gets its centimetre-level RTK position corrections over the mobile network, so it needs no base-station antenna in the garden. The same modem chip sits in the Unitree Go1 and Go2 robot dogs.
Wi-Fi and Bluetooth: EA6621QF module Read
A small shielded module on the computer board, marked EA6621QF on its chip with a 40 MHz crystal beside it, feeds a cable to a Wi-Fi antenna fitted into the mower's shell. A separate Bluetooth module with a printed antenna sits at the board's corner.
The chip marking is fully legible; which company makes it is not printed, so we do not name one.
Motor and safety controller: GigaDevice GD32F427ZGT6 Read
The big driver board is run by a GigaDevice GD32F427ZGT6, a 144-pin Arm Cortex-M4 microcontroller with 1 MB of flash. It sits in the middle of the board, fenced by a solder frame, away from the power stages.
Why a second brain. Linux is not trusted to stop a spinning blade. A separate real-time chip drives the motors and can cut them the instant the mower is lifted or tilted, whatever the main computer is doing.
Three motor drives Inferred
Along the driver board's top edge sit three matching banks of power transistors, three per bank. That is the layout of three separate brushless motor drives: one for each rear wheel and one for the blade.
The motors themselves were not opened; the three-drive reading comes from the board layout.
Long-range radio: Si4463-type chip Inferred
A shielded can on the driver board holds a chip marked 44632A with a 30 MHz crystal and its own flat antenna, marked PCA8530-2A. That marking and crystal match the Silicon Labs Si4463, a sub-GHz radio for slow, long-range links.
The chip maker is our reading of the marking. What the mower talks to over it is not printed anywhere on the board.
Battery: NBCF2213A, 276.5 Wh Read
A Segway Navimow lithium-ion pack, NBCF2213A: 21.6 V, 12,800 mAh, 276.5 Wh, made by De Power Technology. Its cell code, 6INR19/66-4, means six cylindrical cells in series, four in parallel: 24 cells of the 18650 size in all.
Segway sells the X3 with 6, 8, 10 and 12.8 Ah batteries. Only the X390 has the 12.8 Ah pack, which is how we know which model this is.
Every chip on both boards is readable: the processor, memory, storage, power chip, 4G, Wi-Fi and the motor controller. Compare the Unitree robots in this library, where the processor and several radio chips were ground blank before testing.
Parts on this page that we have also found inside other robots in the library.
Battery
The X390 pack is NBCF2213A: 21.6 V, 12,800 mAh, 276.5 Wh, 24 cells in a 6-series, 4-parallel layout. A replacement must match the voltage and the connector; the smaller X3 models use lower-capacity packs, so check the label on yours before ordering.
Boards
The computer board and the driver board are separate, joined by cables. A fault in motor control or charging usually points to the driver board; a fault in maps, app or 4G to the computer board.
Questions
What processor does the Segway Navimow X3 use?
An Allwinner MR527, an 8-core Arm processor, with 4 GB of Rayson LPDDR4X memory and a 32 GB Rayson eMMC, on a computer board marked Chameleon_cpu. A separate GigaDevice GD32F427 microcontroller on the driver board handles the motors and the safety cut-off.
What battery does the Navimow X390 use?
A Segway pack marked NBCF2213A: 21.6 V, 12,800 mAh, 276.5 Wh, made by De Power Technology. Inside are 24 cylindrical lithium-ion cells of the 18650 size, six in series and four in parallel (cell code 6INR19/66-4).
Does the Segway Navimow X3 have 4G?
Yes. The unit that was taken apart has a Quectel EC25 LTE module built on a Qualcomm MDM9207 modem. The X3 uses the mobile network for its RTK position corrections, so it needs no base-station antenna, and for the app when the mower is out of Wi-Fi range.
Based on laboratory teardown photographs of an X3-series test unit, 2024. The photos are not reproduced here; board sizes are approximate. Production units may differ. Not affiliated with Segway or Navimow. Spotted a mistake? Tell us and we will fix it.
Adem Inside