Kookabus-01

The problem it solves

A battery-powered robot stops when its pack runs flat, and changing the pack means switching everything off: the computer reboots and the job starts again. Most packs give no warning either, so the first sign of a flat battery is a machine that has stopped.

Kookabus-01 takes two packs at once. Unplug the empty one and the other carries the load with no brownout. The board reports voltage, current and power over I²C, so your code can ask for a swap before the pack runs out.

Packs: 2 × 5S lithium-ion on XT606S maximum, 12 to 25.2 V per input
Output: 1 × XT60, 100 W peak40 W continuous, 2.7 A typical
Fuses: 2 × 10 A ATO bladeShip separately, fit before use
Swap: Ideal-diode ORing, no brownout20 mV drop, reverse-polarity tolerant
Monitor: INA226: volts, amps, watts1.25 mV and 0.5 mA per bit
I²C: 0x40 default, 0x41, 0x44, 0x45Qwiic and PiicoDev, 3.3 V from the host
Size: 64 × 62 mm, four M3 holesPrintable enclosure with DIN-rail clip
Status: Rev 2, AUD $59Available 25 October 2026

What it does

Kookabus-01 joins two lithium-ion packs into one uninterrupted supply for a robot or other mobile load. Each pack feeds an ideal-diode stage, so the higher-voltage pack carries the load and a pack can be unplugged and replaced while the other keeps the bus up. A high-side sensor on the output reports bus voltage, current and power over I²C, and an LED beside each battery connector shows which pack is supplying the load.

The board is a power pass-through. It does not regulate, charge or balance, and it needs no configuration to swap packs. Only the sensor and LEDs need the host's 3.3 V.

Hot-swappable battery supply for ROS 2 and other mobile robots.
Battery monitoring for Raspberry Pi, Jetson and microcontroller hosts.
Bench supplies from cordless-tool packs such as Ryobi ONE+ and Einhell Power X-Change on XT60 adapter leads.

Find what you need

SpecificationsRatings, electrical characteristics, connectors, jumpers, I²C registers, schematic, protection and mechanical drawing. CodeGetting started, and working examples for MicroPython, Arduino, Linux Python, Linux C and the kernel driver. EnclosureThree-part printable case with DIN-rail clip. STL, STEP and FreeCAD files. Datasheet, PDFEverything on the specifications page in one printable document.

The board

Annotated top view of Kookabus-01 with every functional block labelled — Annotated top view. Open the image for a larger version.

J1, J2: BATT A and BATT B. Male XT60 pack inputs.
J3: LOAD. Female XT60 output, nose overhangs the right edge.
F1, F2: ATO blade fuse holder for each pack. Fit 10 A fuses before use.
U1 Q1, U2 Q2: Ideal-diode stage for each pack: MAX74700T controller and AO4262E 60 V FET.
C15: 100 µF output capacitor on VLOAD, in parallel with 4.7 µF ceramic.
R1: 5 mΩ 2512 shunt, Kelvin sensed.
U3: INA226 voltage, current and power monitor.
U4: MCP6002 comparator driving the two active-pack LEDs.
LED A, LED B: Red beside BATT A, yellow beside BATT B. The lit one is supplying the load.
J4, J5: JST SH 4-way I²C connectors, wired in parallel.
A0, A1: JP1 and JP2, INA226 address jumpers.
PU: JP3, cut to remove the 4.7 kΩ pull-ups.