marcello608
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Joined: Fri Sep 21, 2018 2:01 pm

Suitable power bank for PI3

Fri Sep 21, 2018 2:10 pm

Dear members,

Very new to the Raspberry PI.

I am wondering, would a power bank with 6000mAh and with output 5V/2.1A, but suitable for basic (small) projects with the PI3? (I know output of 2.5A is recommended) but I happen to have a 2.1A that I like, so wondering if this would work, too.

Thank you very much in advance for your advice.

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mahjongg
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Re: Suitable power bank for PI3

Fri Sep 21, 2018 4:26 pm

Try it, if you get undervoltage warning, then your powerbank is not suitable to power what you are doing with the PI.

how much current is needed depends on what you are doing, for example adding power hungry USB devices, or running GPU intensive software will draw more current.

W. H. Heydt
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Re: Suitable power bank for PI3

Sat Sep 22, 2018 5:37 pm

You can get powerbanks rated to provide 2.4A at 5v, which would give you a better margin for a Pi3B/Pi3B+ (especially the latter as it is known to be a bit more finicky about its power supply).

This is also why I tend to favor Pi2B boards for battery powered systems, unless the extra CPU performance is really required. It's also why I have some slim hope that the required current for 28nm parts will at least stay the same and possibly go down.

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Imperf3kt
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Re: Suitable power bank for PI3

Mon Sep 24, 2018 12:59 am

mahjongg wrote:
Fri Sep 21, 2018 4:26 pm
Try it, if you get undervoltage warning, then your powerbank is not suitable to power what you are doing with the PI.

how much current is needed depends on what you are doing, for example adding power hungry USB devices, or running GPU intensive software will draw more current.
Also of possibility could be a bad USB cable or connections.
From my experience, this is the more pressing concern. The Pi will run quite happily off even 0.5A (just the Pi), but the USB connections add large impedance causing a voltage drop.

There is also the possibility of fake or misleading specs. I have seen some USB power supplies claim 2.1A, yet after inspection, the chip inside is only rated for 0.7A, so I do not know where the 2.1A comes from.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

bertlea
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Re: Suitable power bank for PI3

Mon Sep 24, 2018 5:28 am

I tried many 2.1A to 2.4A chargers on my Pi3B and they all works fine even stress tests using Recalbox to play games as long as I use a good USB cable. I found all my issues with power were caused by low grade USB cables. I have no experienced under-voltage issues after I found some reliable AWG20 rated cables.

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