Hi Ian
On (16 Nov 97) Ian Woofenden wrote to Alec Cameron...
 AC> Solar panels operate at about 50% efficiency, to charge a 12v
 AC> battery you use a panel with an output of about 30v.
 IW> Where are you finding PVs with this sort of output? Most panels
 IW> available here are around 20 to 22 volts open circuit voltage.
I say, about 30 volts. I run a 16v system- paralleled 12v auto batteries, the
lot in series with two industrial wet nickel alkaline cells. This gives me
generous lamp performance after sun- down, and ample performance from solder
irons and small bench grinder. A 100watt 240v inverter is able to run other
loads including the house TV and antenna booster, thru occasional power cuts.
I live in an isolated village of 1400.
The open circuit voltage is presumably dependent on sun brightness which in
turn is best in equatorial regions since at other places the sun gets
filtered by that dense dirty air, and the sun rays have a longer route thru
the air, when Sol ain't almost 90 deg overhead.
I wouldn't disagree with you on your 20/22 v values but I assure you, if a
source can only deliver 20v at open cct then it will not deliver its maximum
power at 12v, and much less at 13.8v.
No very great loss, except for those economical installations like off- the -
grid rail signals, water navigation lamps and isolated public phones. These
tend to rely on trickle charging from the panels, without the luxury [and
vulnerability] of a regulator. AUS has a very high isokeuronic level. Hell I
forget the spelling, it means lightning/ thunder frequency.
 IW> ... "Is your gas gauge broken?    Yeah, I fix it all the time."
I guess you remember the early VW beetles- low fuel consumption, no gas 
uge.
This boring guy talked ceaselessly about his- before it was delivered and for
weeks after. Reckoned he was going to travel 550 miles before the second fill
of gas was needed. I think there was a reserve compartment with a change
valve?
Anyhow the workmates got irritated by his cries of joy each day as the speedo
clocked 500, 530, 560 so they decided to punish him. On the quiet they added 

gallon without his knowledge.
You can imagine his wonder and mania.  Thru 580, 600 he would jump on every
individual and quack, quack about that remarkable auto. Until on the second
fill the "mates" secretly milked a couple of gallons, and in the months
following they kept fiddling with that tank and the boring guy became
depressed and excessively quiet and I wondered whether he suffered any
psychological damage in the process.  Cheers....ALEC ;-)
 IW> ... The difference between a developer and an environmentalist: A
 IW> developer is
 IW> building his house now; the environmentalist built his house last year.
When the environmentalist got to my age, he pulled down the hoose and rebuilt
it thar but better, with recycled materials.
... ........Good and quickly seldom meet
--- PPoint 1.92
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