Unplugging the Go2's battery and charging it externally with the charger can be inconvenient — especially when you are testing things and the dog isn't moving anyway.
My Go2 Pro has charging contacts ("nipples") on its belly that allow it to be charged through metal pads on the floor.
The following is a summary of what I found out. Note that different Go2 models may behave differently.
I use this setup regularly and have had no problems, as long as I follow the note of caution below.
I do not accept any liability — use at your own risk.
Charging Nipples
The drawing shows the position of the charging nipples and how they are connected to the dog's internal XT30 power connector. There is a reverse polarity protection circuit in case the charging pads are placed the wrong way around. The diode is just a symbol — most likely a MOSFET is used.
DIY Pad
I bought two 15×15 cm brass plates from Amazon and soldered two cables with an XT30 plug to them. The XT30 connector pins are connected as follows:
Then I designed a simple frame for the plates and 3D printed it:
The frame consists of two 3D-printed parts that hold the brass plates at the correct spacing and keep them from shifting when the dog steps onto the pad. You can download the STL files here: ladeplatte_parta.stl and ladeplatte_partb.stl. I printed them in PLA with standard settings — nothing about the parts is mechanically demanding, and there are no supports required.
Charging
When I connect the original Go2 charger, the battery charges until it is full.
Here is a partial charging curve of the Go2 charged over the pad. I did not record a complete charging cycle.
A Note of Caution
I always turn on the robot before applying power to the charging pads and have never had any problems with this approach. The battery has an integrated BMS, so applying the charging voltage through the pads should not be an issue.
Two warnings:
- Don't apply the voltage while the robot is powered down. I often got an error when doing so (red blinking front light).
- Don't walk the dog while an external supply voltage is connected, especially with a nearly full battery. Back EMF from the motors can produce voltage spikes that may damage the electronics when the battery is already at maximum voltage.