[nSLUG] Powering a RPi (was Re: Cellular dongles)

Joel Maxuel j.maxuel at gmail.com
Mon May 27 09:06:09 ADT 2019


I may as well add this to the greater groups at this point.

Considering what I plan to attach to the RPi, I will want to ensure all the
power I can get:

- Two Phidget InterfaceKits (an 8/8/8 and a 0/16/16)
- A RaZberry2 (https://z-wave.me/products/razberry/)
- The E303 cell dongle

What complicates the situation is that the RaZberry sits on top of P1
(covers the top ten pins) although there is a spot on the RaZberry to
solder on another header to use those ten pins covered:

https://raspberrypi.stackexchange.com/questions/11787/would-it-be-possible-to-use-both-a-razberry-z-wave-and-a-raspbee-simultaneously


 As long as enough power can pass through back down to the RPi, it should
be fine.

Additionally, I would want this battery-backed as I will be using it to
send a notice in the event of a power loss.  I could use an existing UPS,
but avoiding additional power conversion (battery DC to wall wort AC back
to DC for the RPi) would make more sense here.

I will eventually (in some years[1]) have a 12VDC lead-acid bank to work
from, so my interim solution should be setting up something that will be
easy to adapt to that as well.  (Or, since I need to add a marine
battery[2] to the basement next month anyway, maybe I should run a couple
wires and adapt from that?)

[1] As part of a future-planned solar-electric system.

[2] Whenever the power goes out during or shortly after a rain storm, my
basement starts to flood at the 20 minute mark - so getting a
battery-backed emergency sump to complement the existing one.

--
Cheers,
Joel Maxuel

"One should strive to achieve, not sit in bitter regret."
 - Ronan Harris / Mark Jackson


On Sun, May 26, 2019 at 2:11 PM Dave Flogeras <dflogeras2 at gmail.com> wrote:

>
> On Sun, May 26, 2019 at 8:06 AM Joel Maxuel <j.maxuel at gmail.com> wrote:
>
>> Interestingly, when I looked up the E173, the bands did not match my
>> provider.  However the E303 does and appears to tick the other boxes.
>>
>> So I took a risk (or two since it is a Huawei being shipped from the USA).
>>
>> Cool, let me (and the group(s)) know how this works out.   Another data
> point is always better.
>
> At the same time, I may need to borrow a RPi once I get to a specific
>> phase of prototyping.
>>
>> Unfortunately I'm probably not a great resource there, mine are generally
> fully provisioned running bits of my network.  However, I will mention
> this:  Most cell modems are _quite_ power hungry.  I know on older
> raspberry pi hardware versions, they had issues when you powered via the
> micro usb port.  Even if you had a beefy wall-wart milliamp wise, you were
> still putting everything through the little polyfuse which didn't like
> heavier drawing devices.  I'd recommend reading if they did any corrective
> measures on newer hardware (if you have access to say a 3 or 3+).  If not,
> you may need to power it via the GPIO header P1, which supplies the voltage
> after the polyfuse.
>
> I can happily help you out making any cabling necessary, or explaining
> better in the future.  Just ask
>
> Dave
>
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