Boost to buck, I’m sure there’s a better way.

[/RaspberryPi]

Hi all,

Ive got a project that I’m working on that uses a raspberry pi, a small, round display, and a sting of ws2128b leds. I’d like to be able to have the project run on a wall adapter and then switch to battery power to make it mobile. The display, pi, and leds run on 5v and the whole shebang draws about 3.5 amps. Ive got a 5v power supply into a boost converter to 8.4 volts, to a pair of 18650 batteries in series with a balance board. From there, the 18650s got to a buck converter to get me back to 5v. When connected, the buck converter gets very hot, like hot enough to deform the 3D printed case. I’ve also got a branch from the 5v power adapter directly to the pI, display, and leds. I don”t mind running off a single 18650 but I couldn’t find a boost converter that would allow for the current I need. Typing this out makes me think even more that there’s got to be an easier way. I”m also not sure that power will switch to the battery when I unplug it. I haven“t tested that yet, since the buck converter got so hot.

To complicate things further, it’s all got to fit in a tight space.

My question: Is there a simpler way? I’ve already tried to run the display on 3.3 v and it didn’t work.

Everything I could find only talked about just powering the pi from a battery or a power adapter but nto both.

Info:

18650s are Samsung 35E

Boost converter is an XL6009

Buck converter is an LM 2596

Any helo is greatly appreciated since I’m kinda stumbling my way through this.

I”m in mobile so please excuse typos.

edited to correct current draw
submitted by /u/agermane
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Source: https://www.reddit.com/r/raspberry_pi/c ... etter_way/