How to Battery Power Raspberry Pi 3 B+ and Pi Touchscreen?

Question

Hello everyone,

My question is, would it be possible to power the Official Raspberry Pi Touchscreen and Raspberry Pi 3 b+ from a lipo battery?

Any recommendations? I have tried the Power Boost 1000c from Adafruit. The touchscreen draws too much for the 1000c.

Thank you for your time and help.

Trent

shabaz · Answer

Hi Trent, I just tried it now too, with an Anker power bank and it failed with that too after just a minute. Unfortunately I think the easiest way could be to run from a higher voltage battery pack (e.g. two 18650 cell holders) and use a step-down DC-DC converter (maybe an off-the-shelf module for that) to 5V. That will be the quite efficient, and should then provide a couple of hours of power perhaps. (And remove the 18650 cells and charge them in a separate charger(). Also, many chargers are quite bad, it could be worth setting a reminder (e.g. alarm clock on your mobile) to remember to disconnect the cells after they should be charged.

Problemchild · Answer

These are OK and deliver a couple of A + per port .... Also you can charge and power the RPI etc at the same time!: https://www.amazon.co.uk/Zendure-Power-Bank-6700mAh-Ultra-durable/dp/B01AXZUMOK/ref=sr_1_8?ie=UTF8&qid=1538520684&sr=8-8…

afmishaq · Answer

Hi Trent, What a coincidence, I was also thinking about powering a RPi 3 B with 3.5 inch tft screen for standalone operation, earlier today. While there are some power banks that will allow 2A+, these will not be able to provide power for long and also I am not sure how long the batteries will last with such brisk recycling. One option that I had in mind was using a 12V SLA battery with DC-DC buck converter. Not very elegant or portable, but it should provide dependable operation. Charging can be done using house current or solar.

shabaz · Answer

Hi Falah,

It varies versus time (and load). It is not constant.

See below for a screenshot (time in seconds on x-axis) for the boot-up sequence for a Pi 2B. The Pi 3B has very similar current consumption, except when under load.

Some figures for different typical loads, and the delta for WiFi, are here:

https://raspi.tv/2016/how-much-power-does-raspberry-pi3b-use-how-fast-is-it-compared-to-pi2b

You battery would need to be capable to supply 5V at around 400mA current at least (and preferably more, because with heavy loads this will be insufficient).

You can see from the screenshot above that it peaked briefly very close to 400mA just during startup.

genebren · Answer

Hi Trent,

There are DC-DC boost converters out there that can generate up to 2A at 5V from a single Li-Ion battery. Not quite in this range, but I recently developed a boost circuit for my robot project (Walky the Biped Robot - Power pack ) that was able to produce a solid 500mA at 5V (maybe more, as I did not want to push it too hard). It should be possible to extend this design (new boost circuit) to get into the >2A range. But if you need more, then shabaz might be on track with his multiple cell and a step-step converter.

Good luck!

Gene

cypresstwist · Answer

I had a 3.5” touchscreen TFT laying around and decided to try it out. It works. Video below. This is with only one 14500 battery but two should give you double the time. My guess is one such battery with this HAT should be enough to power the Pi+screen for an hour.

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cypresstwist · Answer

This might work: Li-Ion Battery Hat from Waveshare . It uses a 14500 battery but you can connect more to it. I'm using it with a Raspberry Pi Zero W, a Touch PHAT and a small OLED screen I've soldered to the board. Lasts about 3 hours on idle. I think it might be able to power a 3.5” TFT.