[aprssig] Solar BS (Bulletin Station)

[Bill Arthur]

If you want to run your setup year round you won't really know the 
requirements until you've had it going in your backyard all winter.
I've set up a digipeater/wx_stn and have had to increase the solar 
capacity greatly.
My setup uses 380 mA for Raspi, TNC, wx setup and receiver. It has a 10W 
transmitter.
This winter I had lots of sunless days, in one instance eight in a row.
I had to upgrade my system to a 75W panel and 120Ah battery.

On 5/11/2021 6:43 PM, Ev Tupis wrote:
> Thanks to Bob and Steve for the insight I was looking for.  The math 
> is pretty simple.
>
> I'm off to give it a go!
>
> Ev, W2EV
>
>
> On Saturday, May 8, 2021, 1:04:15 PM EDT, Robert Bruninga 
> <bruninga at usna.edu> wrote:
>
>
> Beacon Power budget:
> - XCVR assume 1 amp 100% of time = 1 A
> - XMTR assume 10 amps 0.3% of time = 0.03 A
> - TNC  assume 50 mA 100% of time  = 0.05 A
> Total average current  -                        1.08 A
> Times 24 hours a day                          28 AHrs
>
> 28 AH per day divided by Avg Solar Radiance per day (4 hrs for
> Maryland) 28/4= 7 Amp solar panel
>
> But there may be cloudy days so plan on a full size car battery with
> maybe 80 AH capacity and maybe 12 Amp panel
>
> Noice that the Receiver is the #1 load by far.  Keep volume all the
> way down and measure it exactly rather than using my 1 Amp guess.
> It will make a huge difference.  Then recalculate.    TX power is 
> insignificant.
>
> Bob
>
> On Sat, May 8, 2021 at 10:37 AM Ev Tupis via aprssig
> <aprssig at lists.tapr.org <mailto:aprssig at lists.tapr.org>> wrote:
> >
> > I'd like to setup an APRS-based Bulletin station for a special event 
> to convey helpful information to attendees who are likely to be from 
> out of town.
> >
> > It needs to be solar powered for portability.
> >
> > Would someone be willing to help me with a power budget and 
> suggested panel and battery size?
> >
> > Kantronics KPC3 and 60-watt Transceiver
> > TX ID every 5 minutes with a single bulletin packet
> >
> > It will not digipeat in this application.
> >
> > Ev, W2EV
> >
> > PS: If this is helpful to the responses, in the future it may be a 
> fill-in digi for other events...but not right now
>
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