# CM 4 based tablet - battery managment - what can you recommend?

**URL:** <https://forums.pimoroni.com/t/cm-4-based-tablet-battery-managment-what-can-you-recommend/28768>\
**Category:** Projects\
**Created:** [March 11, 2026, 6:46pm UTC](https://forums.pimoroni.com/t/cm-4-based-tablet-battery-managment-what-can-you-recommend/28768 "2026-03-11T18:46:34Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![thalla](https://avatars.discourse-cdn.com/v4/letter/t/b2d939/32.png) [@thalla](https://forums.pimoroni.com/u/thalla)\
**Post date:** [March 11, 2026, 6:46pm UTC](https://forums.pimoroni.com/t/cm-4-based-tablet-battery-managment-what-can-you-recommend/28768/1 "2026-03-11T18:46:34Z")

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Hi there,

i just started tinkering with raspberry .- and as first project want to try a eink-Tablet - mainly for taking notes.  
So i got a CM4 - and will use something small/flat like Pionura as carrier.  
Connected to that will be a touchscreen controller + touchscreen and a ein-Display Controller + Display.

Now my main question is about battery managment. I want to use “normal” batteries - 21700 - probably 4 of them. As eink does not draw much power when not refreshed i try to go for long battery life.

Does anyone have experience with battery powered devices like that? Can you recommend a power supply that can fit? I tried AI for some suggestions - but if you ask something like that more then once you get different answers. And since i prefer things not to blow up i’d prefer a human advice anyways.

Any tip is appreciated.