[MLB-WIRELESS] Solar power for nodes
Michael Nardella
michaeln at telstra.com
Sat Mar 29 10:12:37 EST 2003
I found batermaster quite good on price and range. Cheaper than
batteryworld. www.batterymaster.com.au tel: 03 9563 8460
Whilst jaycar is cheaper, I think you'll find they are cheaper quality
as well.
Michael
AA Michael Nardella Real Estate P/L
118 Maroondah Hwy
PO Box 4229
Ringwood, Vic 3134
(03) 9870 0111 Fax (03) 9870 0088
General Email: office at nardella.com.au
----- Original Message -----
From: Clae <clae at tpg.com.au>
Date: Saturday, March 29, 2003 6:29 am
Subject: Re: [MLB-WIRELESS] Solar power for nodes
> >Hi Does anyone have any good references for sites about how you
> go about
> >sizing the solar pannel and batteries so that you can reliably
> power an
> >access point using 1-2 watts? Have not had much luck finding good
> sources>for this material.
>
> Check out the website of the Alternative Technology Association
> http://www.ata.org.au and the Solar working group
> http://melbourne.wireless.org.au/wiki/?WGSolar
>
> The Australian standard for sizing a battery bank is to run for
> five
> days with no charging input, and to discharge lead-acid batteries
> only 30% of capacity over that time. Lead-acid batteries will
> suffer
> reduced lifespan if they are fully discharged. NB this only
> applies
> to deep-cycle batteries, normal car batteries are designed to be
> constantly topped up.
>
> NiMH batteries will handle a full discharge without complaint, so
> even though they are more expensive per watt-hour, it's worth
> looking
> into them. Jaycar seem to have the cheapest ones (cheaper again
> for
> 10+ quantities), but try Battery World as well.
>
> I would personally aim for at least two or three days without a
> top-up - this will account for a string of cloudy days.
>
> Multiply the power draw (1 -2 watts) x 24 hrs x no of days to get
> a
> size in watt-hours for the battery bank. If you are using NiMHs
> just
> use that number. If you are using lead acids, multiply by 3 to
> allow
> for the shallow discharge. Round up to a nice round number to
> allow
> a safety margin.
>
> ( and 1 Wh = 1000 mWh )
>
> You'll want at least twice and probably three times the device's
> current draw on your solar panels, so that there is enough power
> to
> run the appliance and charge the batteries at the same time. And
> add
> one of the low-cost solar battery regulators, in kit or module
> form,
> from
> jaycar.com.au, oatleyelectronics.com, or a solar supplier. This
> will
> extend the life of your batteries by regulating the charging, and
> stop them from discharging into the panels at night.
>
> Keeping your batteries cool and away from direct sun will help too.
>
> Clae.
>
> --
> Arthur C. Clarke wrote "Any sufficiently advanced technology is
> indistinguishable from magic" and for those who don't study
> science,
> the "sufficiently advanced" bar is low enough that scientific
> credibility can attach to unscientific belief.
> http://www.chipcenter.com/columns/rci/tesla/tesla4.html
>
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