Al salaam a'alaykum Bob

28 Dec 03 09:13, Bob Lawrence wrote to David Drummond:

 BL>> With a 150 AH battery, you don't have to worry about saving a
 BL>> few lousy amps.

 DD>> 150AH? I was sure I'd said 450AH..

 BL>  It's so far outside my reality that Ican't bring myself to believe
 BL> it. How about I just write "huge"?

Huge? How about just big. By RAPS standards my system is not huge.

 DD>> It does seem like a lot but a few overcast days and it sure
 DD>> pulls down with the fridge running 24hrs. 

 BL>  The greedy electricity users are hot water, heating, the fridge,
 BL> cooking, and air conditioning... all in the 1200W+ range.  Lighting,
 BL> TV, computer, etc are in the 100W range. Hot water is a solar
 BL> certainty (unless you use a fuel stove with the hot water tank),
 BL> cooking and heating can be wood-burning, and air conditioning is out
 BL> of the question. That leaves the fridge, and I'd have gone for LPG 
 BL> and bring the weekend meat with me.

It is most unusual (according to all of the literature I've read) for solar
powered systems to use electricity for hot water, heating or cooking. I've
not seem much mention of air-con either, obviously because it's an
electricity hog too.

I use the electriciy primarily for the refrigerator, lighting, and running
the little audio system. Eventually I'll have a "composting"
toilet. That requires a little 12v fan (think computer PSU) running 24/7

 BL>  You're still stuck with a few hundred watts for the electrics, but
 BL> they're only intermittent ( a few hours at a time).

When I'm in residence the fridge is turned on 24 hours. In the warmer
weather its duty cycle is about 40%. I'm thinking of putting an extra layer
of insulation around it....

All of solar powered blurb sites on the web write of not expecting more
than about 6 hours of usable sunlight per day. I have some tall trees on my
property which shade the panels for some of the day. It seems I cannot have
shade and sun at the same time (maybe I'll have cake and eat it instead).

At this time of the year I can see a charge rate of 20amps going into the
battery during the middle of the day. In the cooler months when the sun is
lower it's only about 3-5.

I could cut down the trees - but that would make it a whole lot hotter (and
the fridge duty cycle would get worse). The anti-tree clearing laws may
have something to say too...

A thirty metre tower with the panels near the top (and a space for a wind
turbine - it's breezy at the top of the canopy) would see more production.
Towers of this nature can be a tad expensive.

Regards,
David

--- Msged/LNX TE 06 (pre)