Solar power questions

 

I'm interested in trying to use Solar power, but so far don't
know anything about it. I want to charge some deep
cycle batteries during the day, and use them to run a
heater for a few hours at night. Even if it takes two days
to charge the batteries I'd be better off just paying for
the heater every other day, than every day. Of course
I'm looking for the cheapest way to do it, since the idea
is to save money. Here

1. What is involved other than the solar panels, wire
and batteries?
2. What would keep the batteries from getting overcharged
and burning out?
3. Would the inverter (Coleman PMP 2000) alone be enough
to regulate when the batteries become dangerously low and
shut down discharge, or would I need to monitor it and do it
myself to avoid damage to the system.
4. How could I monitor the charge level of the batteries?
5. Do the panels only work when there's a certain amount
of light available, or does their performance fluctuate depending
on how much light they're getting at the time?
6. How to calculate what it would take to run a 1.5 KW heater
for a certain period of time, using whatever number of 115
amp hour batteris it would take to get a few hours of use from
the heater, and what type solar panels to use, etc?

I'm sorry to be so completely ignorant, and would appreciate
any help in overcoming it.

 

dh@. wrote:

Well, there are a whole nother bunch of solutions better for heating
than pv, like solar water heating.


charge controller, disconnects, fuses ....


charge controller.


most inverters have a low voltage shut-off, but they usually will draw
more than 50% from the batteries before doing so. best thing is a kWh
meter showing input and output.


kWh meter.


fluctuates


1.5 kw x 2 hours = 3kWh's
115ah / 2 = 57ah usable x 12v = 684 wh each. 3 kWh / 684 wh = 5
batteries. Would need 1000 watts of pv and 3 full hrs of sun to recharge
in one day, or 500 watts for 2 days charge, 2 hours discharge. Some
locations get more or less sun.


Some of us are happy to help. Others will insult you, or the answers we
give.


--
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html

 



From what little I've learned, it would be much more cost effective to use
the power of the sun to heat water. Then use that hot water to warm your
house.

PV is very inefficient, and very expensive.

 



dh@. wrote:


That's the trouble. PV takes a very long time, (if ever), to see a
return when pitted against the grid.

Say your installation runs $8/watt. Now use this:
http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/
Flat panel tilted south, annual, average.

Say it is 5kwh/m^2/day. That gives you about 5wh/panel-watt/day.

In twenty years that's 36kwh, or if you buy it from the grid at
$.08/kwh, about 3 bucks. So, even if you don't have maintenance, you are
paying $8 for $3 worth of electricity with twenty years of use.

Best, Dan.

 



Why photovoltaic cells, necessarily?  The Enviromission solar power tower
looks very promising for harnessing solar energy in a very cost-efficient
way.  Solar collection arrays have shown alternate methods of converting
sunlight to steam.