Creating a airpods like charging case for the FP4 battery

Hi All,

I am looking into creating a airpods like charging case that I can use to charge a fairphone battery through usb-c. I currently have an idea to use the TP4056 and 3d print a case where the battery slides in. The only issue I am currently facing is the connector for the battery. Does anyone know the name for it? It looks like the battery has sideways pogo pins to connect to the flat pins in the phone, but I can’t find anything about it online.

I would love to hear if anyone knows the specific name for these!
Of course this entire project will be available open source once I have it all designed and working.


I like do-it-yourself stuff but I don´t really understand what you want to achieve with it.
Are you using apps, which empty your battery faster than you can charge the phone?

The biggest problems for recharging the batterie outside the phone are in my eyes, that you have to reboot the phone every time you switch the batteries and the clips of back cover might break pretty fast (since it´s not made to be opened on a daily base).

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My idea would be to use this for trips where i then have the possibility to quickly swap batteries if need be. Not for daily use. It would make things like long travels or hot summer days where my phone is used a lot a lot easier

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Wouldn’t it be easier to carry a power pack? something like

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I guess it’s also a bit for the design challenge. The battery will only be charged till 80% max by the case as well due to the cut off voltage which is a nice bonus for longevity. I found the connector already in the meantime btw Mista 4 Pin Pitch 2.5mm Blade Batterij Connector Mannelijke En Famale - Buy Battery Connectors Laptop Battery Connector,4 Pin Battery Connector,4 Pin 2.5mm Power Drone Battery Connector Product on It’s a 4 pin 2.5mm pitch blade battery connector.

Buy an extra FP battery and store it in your travel pouch. Its essentially akin to a power bank but instead of using a battery (powerbank) to charge a battery (within FP4) you instead use the FP4 battery directly. The disadvantage is you need to put your phone off (ie. no hotswap), and booting the smartphone up uses a few % of your battery (approx 1-2%). A powerbank is more flexible as you can also use it to charge other machines. You could even create some velcro clip for your powerbank, allowing you to carry it together with the smartphone (at the disadvantage of more weight and size).

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