Repairing Aldebaran Nao Battery Pack

Our Nao recently stopped working due to a completely flat battery.

My boyfriend Renze and I have had it since 2016 and it’s no longer serviced by the manufacturer once the 4 year warranty is up.

Investing in social robots has proven to be a bit tricky. Companies go bankrupt or are acquired (e.g. our Anki Vector robot) and then strategies change, leaving you with some expensive hardware at worst gathering dust on the shelf and at best needing additional investment to keep it working. You might have the hardware but an important part of the package is often cloud based software or development API’s that won’t be maintained and updated indefinitely.

We’ve not used our Nao for quite a while due to other projects but since I recently started a course on robotics which used the Nao, I thought it would be good to dust it off again, only to find the battery completely flat.

Nao’s manufacturer, the French Robotics company Aldebaran was bought by Softbank in 2012 and since then the company has been sold again to German United Robotics Group and will operate under the original name. The focus had switched from the Nao robots which were primarily research robots to Pepper and Romeo service robots. It should be interesting to see what direction URG takes with the products.

We’ve sent our Nao to Softbank in France to be serviced once before, due to its somewhat fragile fingers breaking.

This time we’ve been lucky and it’s only the battery that’s flat and not something more serious wrong with it.

We found a blog post detailing how to replace the dead cells in Nao’s battery pack:

We first removed the battery pack by unscrewing the hatch, then we tested the cells and found them depleted.

We opened the battery pack and it seemed possible to swap the cells and reconnect the circuit board to them.

Next we had to order new cells online (these are standard 18650 Lithium-ion cells) and buy a mini spot welder to weld the zinc connectors to the cells.

This is me spot welding the cells together

We soldered the connectors onto the circuit board and taped the battery pack together with heat resistant tape.

We did some careful testing by charging the battery with the official charger and then installing it back into Nao. Finally our Nao is back in working order! And we’ve gained some confidence and added some new technical skills (and equipment) to our toolkit.

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