WilliyPW
Posts: 1
Joined: Fri Jul 13, 2018 5:52 pm

Rasberry pi 3 b+ battery

Fri Jul 13, 2018 5:59 pm

Hello !

So here, I intend to buy the Raspberry Pi 3 for its built-in wifi.
I just need to know what kind of battery I would need, knowing that I intend to use it only for its wifi and launch some remote scripts.

My question is:
Which external battery could allow my Raspberry to work more than 2 weeks without having to recharge it?

If you have advice on which batteries to avoid (I have seen that amperage and volts are very important data to consider).

Thank you in advance !

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neilgl
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Location: Near Aston Martin factory

Re: Rasberry pi 3 b+ battery

Tue Jul 17, 2018 9:41 pm

I would get a pizeroW rather than a pi3plus as the pizeroW has wireless and uses a lot less power.

drgeoff
Posts: 8633
Joined: Wed Jan 25, 2012 6:39 pm

Re: Rasberry pi 3 b+ battery

Tue Jul 17, 2018 10:03 pm

Back of fag packet calculation:

Take a ballpark figure of 1 amp for the current consumption of a RPi3. That's 5 watts. For two weeks means 1680 watt-hours. For a 12 volt battery that would equate to 140 amp-hours. A typical 12 volt car battery (medium size car) is in the 40 to 60 amp-hour range.

For a USB power bank type of thing the labelled capacity would need to be in the region of 500 amp-hours. Don't think I've seen any above about 20 or 30 amp-hours.
Last edited by drgeoff on Tue Jul 17, 2018 10:17 pm, edited 1 time in total.

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Imperf3kt
Posts: 1386
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Location: Australia

Re: Rasberry pi 3 b+ battery

Tue Jul 17, 2018 10:06 pm

There is no current battery technology that can run a Raspberry Pi for two weeks, without charging it.

Get a solar setup, and prepare for some learning.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

W. H. Heydt
Posts: 9113
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Rasberry pi 3 b+ battery

Wed Jul 18, 2018 1:58 am

Imperf3kt wrote:
Tue Jul 17, 2018 10:06 pm
There is no current battery technology that can run a Raspberry Pi for two weeks, without charging it.

Get a solar setup, and prepare for some learning.
Sure there is...a bank of Lead Acid batteries. Preferably "deep discharge" marine batteries. Not very portable, I'll grant you, but it could be done.

PhatFil
Posts: 530
Joined: Thu Apr 13, 2017 3:55 pm

Re: Rasberry pi 3 b+ battery

Wed Jul 18, 2018 2:17 am

whats the intended job? sounds basic a pi may be well over specified? you might find a less powerful and lower specified soc with significantly lower power demands, possibly esp8266 or esp32

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Imperf3kt
Posts: 1386
Joined: Tue Jun 20, 2017 12:16 am
Location: Australia

Re: Rasberry pi 3 b+ battery

Wed Jul 18, 2018 8:39 am

W. H. Heydt wrote:
Wed Jul 18, 2018 1:58 am
Imperf3kt wrote:
Tue Jul 17, 2018 10:06 pm
There is no current battery technology that can run a Raspberry Pi for two weeks, without charging it.

Get a solar setup, and prepare for some learning.
Sure there is...a bank of Lead Acid batteries. Preferably "deep discharge" marine batteries. Not very portable, I'll grant you, but it could be done.
Fair enough, you have a point. Highly impractical, and probably extremely expensive, but you are technically correct that it is possible with today's technology, or rather, lots of it.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

W. H. Heydt
Posts: 9113
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Rasberry pi 3 b+ battery

Wed Jul 18, 2018 4:17 pm

Imperf3kt wrote:
Wed Jul 18, 2018 8:39 am
W. H. Heydt wrote:
Wed Jul 18, 2018 1:58 am
Imperf3kt wrote:
Tue Jul 17, 2018 10:06 pm
There is no current battery technology that can run a Raspberry Pi for two weeks, without charging it.

Get a solar setup, and prepare for some learning.
Sure there is...a bank of Lead Acid batteries. Preferably "deep discharge" marine batteries. Not very portable, I'll grant you, but it could be done.
Fair enough, you have a point. Highly impractical, and probably extremely expensive, but you are technically correct that it is possible with today's technology, or rather, lots of it.
Much of that solution depends on a possibly unstated requirement. To wit: Does the solution need to be portable (and that in the sense of not requiring a vehicle to move it). Basically, the OP needs to provide more information about exactly what he is trying to do.

It is, of course, possible that a reasonable sized battery system would work if the Pi only has to run intermittently. In that case, an add-on processor that can fully shut down the Pi between active intervals and reboot it when needed. Specifically, an add-on that uses very little power and has a "wake on event" (timer or some signal) capability. Such a scheme (if it meets the needs of the project) could massively reduce the required energy storage requirements. Another alternative *might* be PoE, depending on the project requirements.

The basic problem is that we don't have a full description of the project. We can't evaluate the full scope of the requirements and suggest alternative solutions. This is actually pretty typical of "request for help" posts. Only part of the situation is specified and people ask for further details (not always forthcoming) or guess as to what the *real* requirements are. And when one has to guess, the suggested solution may be kind of...odd.

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