Assuming a hard to get to place, higher latitude with a real winter, I would
say:
1000W of panel. (20X load)
16 kWh storage. (14 days autonomy)
So right in line with Bill's recommendation.
-----Original Message-----
From: Bill Prince
Sent: Tuesday, January 12, 2021 11:55 AM
To: af@af.afmug.com
Subject: Re: [AFMUG] Solar/Battery for Micro-PoP
If your load is 50W, then you need to deal with ~~ 1.2 KWH of energy
usage per day (50*24).
We don't know your latitude, or location, so you will have to plug in
whatever solar values are typical for your area. However, a good rule of
thumb for mid-latitude areas is to have enough battery for 10 days of
operation without sun. So you will need about 12KWH of battery storage.
If you're using lead acid batteries, double that for 24KWH of storage.
Then you will need enough solar for you to recover that in one or two
days. For example, if you have 1200 watts of solar, you can typically
expect to get back 4.8KWH per day (5 hour day at 80%).
A 48V system would be the most efficient. It will require smaller wires,
and converting from 48->24 is more efficient than the other way around.
Separately, I would suggest to examine your sanity for thinking you
might be the only one in the US to make TVWS actually work.
bp
<part15sbs{at}gmail{dot}com>
On 1/12/2021 10:42 AM, D. Bernardi wrote:
Hi,
I'm considering some fixed wireless (TVWS) trials and/or the ability to
deliver temporary service where there's no available power source. I've
done some basic solar system calculations (and there are plenty of
calculators) but I'm looking for some real world pointers from those that
have deployed off-grid micro-PoPs.
DC only, no inverters required. We may need 24v PoE and 48v PoE so would a
48v system with step down to 24v be more efficient than 12v or 24v with a
step up? Other trade-offs to consider for 12v/24v/48v storage systems?
I don't have actual load measurements yet but at this point I'm currently
sizing for a 50w load. The base station and backhaul radios combined
should be ~ 30w.
Thanks,
Dave B.
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