[MLB-WIRELESS] Solar power for nodes

[Michael Nardella]

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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