Battery for the pi 3

[Karl_W_R]

Hi
I want to do a IoT hub project with my Pi 3, the problem is that I want my device to be portable.
I looked in to the specification for the pi3 and it has to have 2A current???

Is there a way to make the Pi more low current? I mean I'm probably not going to use all the gpios and neither the HDMI or Bluetooth. But is there a minimum amount of current the the Pi 3 needs at startup???

And also, is there any good batteries solution that don't cost a fortune for the Pi 3???

Thanks for the help guys

//Karl

[texy]

Hi and welcome to the forum.
The Pi doesn't HAVE to have 2A, it is just recommended. The actual amount of current the pi requires will be dependant on the processes running and the additional hardware connected to the Pi.
Texy

[darkbibble]

the simplest (and cheapest) way is 6aa batteries with a 5v UBEC and a micro usb male connector.

thou there are ups battery systems available that cost about £40 for the ups board and high capacity battery.

[Hagar]

I'm using a power booster pack for a phone, got it as a free gift from screwfix, gives 6000mAh. Will run my pi 3, headless and reading sensors on gpio for about 12 hours no problem.

[Karl_W_R]

Hi All

Thanks for all the info

The problem is that I want to build a IoT device that can Stand alone and send info to my IoT hub for days.

Im not going to run a lot of processes on it, Im only going to sens the room humidity once every 10 min and then send these 10 values every hour to the Hub and the hub is going to calculate the average temperature and then send a command back to the device telling it to turn on a fan and for how long.

So
1) I only need to run the Wifi once per hour

2) I only need power/ current to drive the humidity sensor, the wifi and one GPIO to a NpN transistor for the fan, the fan has its own power supply (12 v)

I know that I could probably do this application using a PIC processor without the WIFI but I relay what to learn how tho connect to a IoT Hub and send a package back to the IoT device. So I need a cheep battery that can power this for at least 3 days.

BR

//K

[RaTTuS]

use a Pi0 or Model A

you are not going to get a cheap battery that will power a RPI3 for 3 days

[mosespi]

Karl_W_R,

How about if you power up and down? I've got a UPS that will do it for you, see "UPS Timer Control Settings" in the manual..

http://www.allspectrum.com/mopower/

You can figure other ways of running it on a timer too. Some calculations for you, hopefully they are in the ballpark!

- Assuming about 5 watts running power.. powering up every 10 minutes for 1 minute gives us 10 times less power or 0.5w power usage.
- We have 18 watt hours in a 6xAA NIMH pack, take 80% for converter losses gives us 14.4wh usable.
- 14.4 watt hours / 0.5w gives us 28.8 hours running time for AA batteries
- Go up to C cells doubles (5AH vs 2.5AH of AAs) our run time to 57.6 hours
- Again up to D cells gives us 115.2 hours or 4.8 days.
- Switch up to a 7AH 12v SLA battery gives us 168 hours or 7 days.

My Pi3 *with* a running 7" display takes 5 watts, so I'm using that as a baseline calculation, I'm guessing your setup will likely be a bit less and you will get a bit more runtime. Model A will likely double all the runtimes.

Regards,
-Moses