If your Anki Cozmo battery if it no longer holds a charge, there’s a really good YouTube video on how to replace it.

That was the case with ours, so I watched it and want to add a couple extra pointers for those thinking of doing the same. The video has just about everything you need to do the replacement, including links to tools you may need to buy.

Tools

I went ahead and ordered the precision screwdriver kit linked from the video. In retrospect, I didn’t need it because I had all of the things I needed already: spudger, small phillips screwdriver, tweezers. But the prospect of being able to work on anything with a specialty screws was appealing.

Plus the case folds up neatly for storage.

Even with all the supplied bits, I still needed another small phillips screwdriver for one of the screws that is deeply recessed. It holds both of the main halves together. It’s the green one pictured below, along with all of Cozmo’s parts.

I put all the parts I took off in a row to make it easy to go in reverse order when putting him back together.

Soldering

This is the section that is sort of glossed over in the video. He shows you what needs to be de-soldered and soldered – the positive and negative battery leads shown in red and green (respectively) below.

I’m not going to go over all the things you need to know about soldering, but there are some important safety details we should cover before starting this replacement. The replacement battery will come with a connector on it, which needs to be removed.

So you don’t short the leads out, you need to clip the wires one-at-a-time. We’re not the FBI diffusing a bomb, but it could light on fire if you short both wires while clipping them at the same time. 🔥

Remember to grab the rubber sticker off the original battery and add it to the new one.

Strip and pre-tin the ends of the wires before snaking the wires through the charging plate to the soldering points. That will keep the wires from fraying, and they’ll be ready to solder to the board.

In addition to having more capacity than the original battery, it is also physically larger. I had to massage the end of the cell (shown at the green arrow below), to get it past Cozmo’s edge detection sensor. Not great considering all of the lipo fires that start due to bad folds, etc.

Fingers crossed that it will be OK 🤞 After that I put everything back in reverse order. The whole thing took me around an hour from start to finish.

Cozmo works great and lasts even longer than he did brand new. A worthwhile replacement/upgrade if you know how to solder.