Raspberry Pi Forums

Hello everyone!
I'm working on a robot project. The core will be a Raspberry Pi 3. I'm just planning to get it to drive around to begin with. I'm looking for a power supply for the Pi (the motors will have a seperate power supply). It needs to be quite small. I'm thinking that I can use a powerbank (one you use to charge for example cellphones). I can't find a power supply that outputs more than 2 amps while still being small. My question is if I can use a power supply that only outputs 1 amp? I looked at this page: https://www.raspberrypi.org/help/faqs/#powerReqs and the bare board consumption stays below 1 amp always, except when at maximum stress. Will it work? If not, can I disable functions of something to reduce the power consumption?

Thanks in advance!

Are you planning to communicate with the pi? Wifi or bluetooth both add load which could be a problem for a 1A power supply.

I have used powerbanks in the past with no issues.

Unless the robot is tiny a USB Power bank just won't cut it.
Could use the power bank for the Pi and a bunch of NiMH AA cells for the robot motors.

A lot depends on robot weight, motor size/power/voltage, stall current, gearing, speed.....
Low voltage 3V toy motors usually need high currents, better if these are supplied direct from AA cells.

Most important is the stall current, robot just won't move unless you can meet those amps.

I use USB power banks for all of my current RPi robots.

Just get power banks with a 2.1A (or higher) output, they are easy to find.

For the motors, I use NimH batteries in 4-6 AA cell configurations, or NiCad RC power packs, or two 3.7V LiON or LiPO cells.

See http://www.mikronauts.com/robot-zoo/

BMS Doug wrote:Are you planning to communicate with the pi? Wifi or bluetooth both add load which could be a problem for a 1A power supply.

I have used powerbanks in the past with no issues.

I'm planning to communicate with the Pi using wifi, but since that is included on the Pi, I assumed that was included in the calculation.

Gavinmc42 wrote:Unless the robot is tiny a USB Power bank just won't cut it.
Could use the power bank for the Pi and a bunch of NiMH AA cells for the robot motors.

A lot depends on robot weight, motor size/power/voltage, stall current, gearing, speed.....
Low voltage 3V toy motors usually need high currents, better if these are supplied direct from AA cells.

Most important is the stall current, robot just won't move unless you can meet those amps.

I'm using this chassis: https://www.adafruit.com/product/2939. It's quite small and that's why I need a small powerbank and I can't fins a small powerbank that can output at least 2 amps. The powerbank will only power the Pi, I will have a seperate power supply for the dc motors, consisting of 4 AA batteries.

Can I power a Raspberry pi 3 with powerbank that can only output 1 amp? The powerbank won't power anything else, except a ultrasonic sensor. The DC motors will have a separete power supply.

No. The pi3 itself takes a couple amps.

ElEscalador wrote:No. The pi3 itself takes a couple amps.

Are you sure?
According to this page it shouln't use more than a little over 1 amp at maximal stress: https://www.raspberrypi.org/help/faqs/#powerReqs.

Without using BT or WiFi, only a small wireless kb dongle, during boot it takes just under an amp.

http://www.mikronauts.com/raspberry-pi/ ... review/11/

If you have any other peripherals, BT active, WiFi active, it will easily hit 1.5A

Also, most 1A outputs, especially on cheap battery packs, drop below 4.8A, and you get the lighting bolt.

Don't cheap out on power.

Nerarith wrote:

ElEscalador wrote:No. The pi3 itself takes a couple amps.

Are you sure?
According to this page it shouln't use more than a little over 1 amp at maximal stress: https://www.raspberrypi.org/help/faqs/#powerReqs.