Re: [Starlink] Starlink power use & satellite tracking

[Nathan Owens <nathan@nathan.io>]

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I ran a Round Dishy in my car for a long time, along with the router, using
a 300W inverter. My car is rated for 12A continuous, 16A peak. Per my
Kill-A-Watt, it drew on the order of 30-50W, sometimes spiking to 80-90W
when obstructed/booting. My inverter is 90% efficient, and never tripped my
car 12v E-fuse. The V3 dish is more efficient, and uses less power.

On Thu, Feb 16, 2023 at 3:08 PM Ulrich Speidel via Starlink <
starlink@lists.bufferbloat.net> wrote:

> In the aftermath of our cyclone here, I got dragged out for a bit of media
> comment and, downstream, a few questions came up on dishy power use. Here's
> what I know and can glean - comments welcome:
>
>    - Starlink's own specs say 50-75 W "Average Power Usage":
>    https://www.starlink.com/specifications. But that's average, not peak,
>    and peak is what matters when people start recommending that Starlink could
>    be run out of a small inverter and a car battery in a disaster.
>    - Small inverters usually come with cigarette lighter cables, and
>    cigarette lighter sockets are typically fused with 8 or 10 A fuses. That
>    puts maximum safe power outputs in the 96W to 130-something W range
>    depending on battery voltage.
>    - Our lab's "RV" subscription rectangular dishy & router regularly
>    clocks in at around 80-100 W, and I've seen it go as high as 108 W on one
>    occasion. I've also seen it go as low as 30 W for the first time last night.
>    - I have a user report from an older round dishy owner having seen up
>    to 200 W on occasion.
>    - Assuming conservatively 90% inverter efficiency, that could mean up
>    to ~120W and maybe more for the rectangular version and over 220 W for the
>    circular one.
>    - If dishy goes over cigarette lighter fuse capacity, people may lose
>    their ability to charge phones from their car - also a critical capability
>    in a disaster.
>       - Not everyone takes kindly to the suggestion that advising
>       inverter + car battery use could potentially be counterproductive.
>       - So, what's the peak power use you have seen on your version of
>    dishy?
>    - It appears that the current mode of operation here is that dishy
>    uses several satellites in parallel if these can all see a gateway and have
>    capacity to carry traffic.
>    - So for us in urban Auckland with few Starlink users in the cell and
>       three gateways in the vicinity, our dishy is spoiled for choice and usually
>       gets to use maybe three or more satellites at once. That takes a
>       corresponding amount of power but also means great data rates a lot of the
>       time.
>       - For a rural user with more Starlink users in the cell and further
>       away from gateways, the satellites that the cell can see and that  can also
>       see a gateway may be fewer in number. This means dishy only gets to talk to
>       maybe one or two birds at a time and so uses a lot less power, and you get
>       more average data rates there.
>    - If this is so, then it begs a question:
>       - If Starlink could cap the number of satellites dishy can use in
>       an emergency area, they would be able to keep your fuse intact. Should they
>       aim for that, even if it means that you might see lower data rates in a
>       situation when many people depend on one unit?
>
> Starlink is currently being touted as THE comms solution for emergencies
> as large swathes of NZ's northern and eastern North Island remain without
> terrestrial or mobile Internet coverage after cyclone Gabrielle. This is
> the outage map of one of the larger mobile phone providers just for these
> areas:
>
> Most of these are due to power outages to sites, but there are quite a few
> backhaul cable issues as well.
>
> One of the biggest problems is that electronic payment systems don't work
> without Internet. In our largely cashless society, this is leading to
> situations where emergency services can't refuel their vehicles because
> their fuel cards won't work, supermarkets and other stores can't sell
> anything because customers have no means of paying, and the air force is
> flying in hard cash in order to help the locals buy food.
>
> --
> ****************************************************************
> Dr. Ulrich Speidel
>
> School of Computer Science
>
> Room 303S.594 (City Campus)
>
> The University of Aucklandu.speidel@auckland.ac.nz http://www.cs.auckland.ac.nz/~ulrich/
> ****************************************************************
>
>
>
>
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