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UPS ideas etc

Z

Zebedee

Jan 1, 1970
0
I have a small 12v solar panel. I'm quite interested in solar power and as
an experiment, did manage to charge my mobile phone battery using the solar
panel although it did take 3 weeks to charge enough to allow 15 minutes
conversation instead of the normal 3 hours.

Obviously the site and orientation of solar panels are very important. I'd
be very interested in running my PC totally from solar power. I already have
a UPS, which is what put the idea into my head. It struck me that as
sunlight is free and inverters are relatively inexpensive as are car
batteries, it would be a nice idea to combine some larger solar panels plus
diodes together with car batteries and an inverter. I'm not sure how much
power my PC uses but from the mains I'm currently running: UPS, halogen
desklamp, a server (standard PC case and PSU), a PC (standard PC case and
PSU), LCD monitor and a modem. For the sake of argument, let's assume that
the two PSUs are 400w and the modem is 100w and about the same for the
halogen lamp. We'll ignore the UPS as that can be retired when solar power
is assured.

Given that car batteries do not like to be fully discharged and that the
PC/Server get 18 hours daily use (the server is switched off 90% of the
time. The halogen lamp is on between sunset and about 3am on average) then
I'd assume I'd need to be able to accommodate 1000w for 9 hours of no
sunlight. Assuming I could get sufficient batteries to provide me with 9kwh,
how large an area would I need to cover with solar cells in order to
generate that amount of power:

a. on a summer's day
b. on a midwinter day

No need to be brutally accurate as it's an interest question only.


--
Yours

Zebedee

(Claiming asylum in an attempt
to escape paying his debts to
Dougal and Florence)
 
Z

Zebedee

Jan 1, 1970
0
Hmm. It does seem that green though it is, the case for solar power is not
really that strong. If every roof in the land were fitted with solar tiles
rather than ordinary tiles, it would probably yield a reduction in energy
generation from other sources of maybe 10%?

Location: Britain. MidWinter we have sunlight from about 9:30am until
4:30pm. Midsummer, from 4am until 11pm.

Weather tends to be cloudy 25% during summer and 75% during winter.

What use would you suggest solar power is best for, given its minimal
contribution? I've seen solar-powered garden lights available although I
doubt they'd produce more than minimal illumination.

--
Yours

Zebedee

(Claiming asylum in an attempt
to escape paying his debts to
Dougal and Florence)
 
B

Bernd Felsche

Jan 1, 1970
0
Zebedee said:
Hmm. It does seem that green though it is, the case for solar power
is not really that strong. If every roof in the land were fitted
with solar tiles rather than ordinary tiles, it would probably
yield a reduction in energy generation from other sources of maybe
10%?

Depends on the time of year. During summer daytime, such an
arrangement may provide more than what is required for domestic use.
In Germany, there are many houses with several square metres of PV
on the roof, connected to the grid, and they have enough to spare to
feed something back on a lot of days of the year.
Location: Britain. MidWinter we have sunlight from about 9:30am until
4:30pm. Midsummer, from 4am until 11pm.
Weather tends to be cloudy 25% during summer and 75% during winter.

Try http://homer.ssec.wisc.edu/~insol/euinsol.html

Gives you insolation onto a horizontal surface. You can fiddle with
the numbers depending on roof angle and orientation.

Early this year, the readings were off-scale; probably close to
zero. Depending on which part of Britain, you could now be soaking
up between 10 and 25MJ per horizontal square metre at ground level.
What use would you suggest solar power is best for, given its minimal
contribution? I've seen solar-powered garden lights available although I
doubt they'd produce more than minimal illumination.

You could move somewhere where the sun shines. :)
 
B

Bill Darden

Jan 1, 1970
0
Actually car batteries are designed for a 5% Depth-of-Discharge;
however, if you could limit the DoD to 10% the available number cycles
would go way up. The heavier the batteries or more Reserve Capacity,
the better.

Kindest regards,

BiLL.......

www.batteryfaq.org
 
F

Fred B. McGalliard

Jan 1, 1970
0
Zebedee said:
Hmm. It does seem that green though it is, the case for solar power is not
really that strong. If every roof in the land were fitted with solar tiles
rather than ordinary tiles, it would probably yield a reduction in energy
generation from other sources of maybe 10%?

I suggest that if this were in fact true, and given no other information
about the relative cost, this is a very big deal, since this 10% can be
increased to 20% by the unpleasant option of loosing around 10% of one of
our other major fuel sources, or the more desirable, increased conservation.
It might, in the end, be enough alone to permit an extremely advanced
society to continue watching TV for entertainment.
 
Z

Zebedee

Jan 1, 1970
0
Fred B. McGalliard said:
I suggest that if this were in fact true, and given no other information
about the relative cost, this is a very big deal, since this 10% can be
increased to 20% by the unpleasant option of loosing around 10% of one of
our other major fuel sources, or the more desirable, increased conservation.
It might, in the end, be enough alone to permit an extremely advanced
society to continue watching TV for entertainment.

Would an advanced society actually watch TV?

--
Yours

Zebedee

(Claiming asylum in an attempt
to escape paying his debts to
Dougal and Florence)
 
F

Fred B. McGalliard

Jan 1, 1970
0
Zebedee said:
Would an advanced society actually watch TV?

Good question. To which I have only one answer.
"Beam me up Scotty, there is no intelligent life down here."
 
A

Anthony Matonak

Jan 1, 1970
0
N. Thornton said:
I made it much higher than that. There was a thread on this recently.

I make it much higher as well. Covering roofs and parking lots with PV
panels could easily provide as much energy as a country like the United
States uses in all forms (oil, gas, coal, nuclear...). Just residential
roofs might only provide as much electrical power as is used today and
this is perhaps around 10% of all energy used but that is, as mentioned
elsewhere, still significant and useful.

Anthony
 
S

scott

Jan 1, 1970
0
Anyone in England might be better served by taking a look a Wind power
rather than PV...

Scott...
 
Z

Zebedee

Jan 1, 1970
0
scott said:
Anyone in England might be better served by taking a look a Wind power
rather than PV...

That's probably right. The only problem is one would needplanning permission
for a wind generator and there'd be the liability if a strong wind blew it
away.

Solar panels are much easier to handle in that way.

--
Yours

Zebedee

(Claiming asylum in an attempt
to escape paying his debts to
Dougal and Florence)
 
D

doh.CeSpamHuh

Jan 1, 1970
0
Zebedee said:
That's probably right. The only problem is one would needplanning permission
for a wind generator and there'd be the liability if a strong wind blew it
away.

Solar panels are much easier to handle in that way.

I use a PV panel to directly drive a couple of fans in a
greenhouse in the UK. It's a perfect use of PV for me,
as the fan speed is roughly proportional to sunlight. When
the sun *does* appear in the UK, it's quite capable of killing
dogs left in cars within 20 mins, let alone hundreds of (carefully
looked-after-for-several-years) plants when you forgot to
turn on the ventilation.. :/
However, there must be other similar ways to *really* utilize
PV energy, rather than going 'off-grid', with all the "inefficiences/
manufacturing pollution/short working life" that goes with charging
batteries?
 
B

Bernd Felsche

Jan 1, 1970
0
That's probably right. The only problem is one would need planning
permission for a wind generator and there'd be the liability if a
strong wind blew it away.

Nobody, except "Shonky Ted's Enguneering" would sell you a structure
that blew away in a strong wind. You wouldn't be permitted to erect
a structure that's not been engineered. Not if local authorities
have any semblance of responsibility.
Solar panels are much easier to handle in that way.

With far less, and less-reliable output.

Your house would be de-roofed well before an Engineered wind
generator tower failed.
 
C

Chuck Yerkes

Jan 1, 1970
0
Zebedee said:
That's probably right. The only problem is one would needplanning permission
for a wind generator and there'd be the liability if a strong wind blew it
away.

In college, some folks, perhaps as a school project, build a tower.
It was about 15' (5M) high. 4 steel posts set in concrete on a concrete
pad. Some cross braces and then wood over that. Sort of an
obelisk/pyramid, but ended before the point.

On the top were two steel barrels. each cut in half and offset
and affixed to a steel shaft that ran to the bottom.
/
(
\X\
)
/

(the second barrel was below and rotated 90 degrees).

The shaft went to the bottom as was attached to an alternator (from a VW
for the first three, then they actually spent $20 for one from a big car.

To stop it, there was a disk on the shaft and a motorcyle brake (and a
stick to keep it stopped once stopped by hand.

Metal stakes were driven into the ground 3M out and guy wires attached.
And eventually nylon ribbons after dogs and people kept walking into them.

The cost was under $100 or so. concrete pad mostly. Some for
the wood that framed it. The rest was scrap.

Wind turned it, the alternator made power that fed a truck battery
that powered the airator on a large fish tank (6' tall, 10' round thing
that was attached to the housing unit in a large greenhouse).

Efficient? Not really. Worked? Absolutely. And paid for itself
within a couple months. Enough that the science dept that maintained
the greenhouse sprung for the "real" alternator.


So don't tell me that wind power is particularly hard.

A real tower would not have wood sheets on it, wind would
pass THROUGH. A metal tower anchored by even a mediocre DYI'er
shouldn't move.

We're not talking Dutch Windmills or grinding grain.
Small wind turbine.
 
C

Chuck Yerkes

Jan 1, 1970
0
Zebedee said:
I have a small 12v solar panel. I'm quite interested in solar power and as
an experiment, did manage to charge my mobile phone battery using the solar
panel although it did take 3 weeks to charge enough to allow 15 minutes
conversation instead of the normal 3 hours.

I have a real panel and it makes enough power to charge my phone in an
hour or so.
Hmm. It does seem that green though it is, the case for solar power is not
really that strong. If every roof in the land were fitted with solar tiles
rather than ordinary tiles, it would probably yield a reduction in energy
generation from other sources of maybe 10%?


OR, a Jail near us put up a 50kw system. They expect that it will pay
for itself in 7 years unless rates go up (pays for itself faster).

They are county, they will not be "moving" or anything.


The Moscone Convention Center is (will be?) covered with enough panels
to power most neighborhoods. More useful, they will not be taking the
power it would take to power a neighborhood.

You drop energy usage by 10%, suddenly, there's 10% more oil or coal or
what have you. Go bigger and use more effcient things and we can stop
invading countries and we won't scan the papers for names of friends who
died in combat.
 
C

Chuck Yerkes

Jan 1, 1970
0
tater said:
Now, I have not heard of anyone doing this, but I have heard that it wasn't
practical

except.......

now car batteries are designed for very low output long time, being able to
store a lot over a period of inactivity, and be able to dump a large ammount
for a very short time.

everyone I talked to said they are the worst for a storage bank, but it
doesn't seem that way to me...
Why listen when you have a theory.

I've got a friend with an offgrid setup. He's 20 miles from grid, so it
was practical in 1979 to do it.

He was using car batteries cause he had them.
He now has a SHED full of dead car batteries that we were
trying to figure out how to get rid of (local Napa won't be
happy to get 80 car batteries).

We've also been trying to convince him to blow the money on
1) real batteries. GolfCart batteries are common, etc.
2) a post 1988 inverter. One that's a bit more efficient.
I think everyone who is sizing their settups are not generating enough
power, hence they make the storage bank take up the slack.

You HAVE to have that bank. Why? well one example.
You're running your vacuum, a big cloud comes by. You're voltage drops.
Now you're vacuum motor is shot. Sorry about that.
I was thinking of a setup where you generate enuf power to support your
needs for 90%(99%?) of the time, and when big surge loads (i.e. motor
startups) you pull off the battery bank. hence the majoity of the time, the
batteries are not supplying current, just like car batteries.
this would mean having power generation at nearly all times (not just
sunlight), integrating steam, solar, hydro, wind, and whatever else you can
Mr Fission. Just toss your trash in.

You want all RE sources, but you're too cheap to by batteries intended
for long use?
get to pull out a watt or two. Also means that at peak brownout times that
all non-essential stuff stops (water heater, fridge, freezer, HVAC) and only
the essentials remain supplied.
Because stoping and starting AC and Fridge compressors SAVES energy?
for the calculators out there, I would size things so that the car battery
bank would only drop down to 90% of capacity at discharge with a duty cycle
of maybe once an hour for 3-10 seconds.

would it then be practical to use car batteries? especialy if you can get
them cheap enough (say from the trade in at an auto shop, I assume 10% of
batteries would be good)

No. The autoshops get dead batteries to recycle the lead and other
bits. To keep them out of landfill.

Why this compulsion for car batteries?
 
C

Chuck Yerkes

Jan 1, 1970
0
N. Thornton said:
The only plus with car batts is you can pick them up for nothing and
fix them for very little. As you point out, they dont last as well.

Yeah, you get what you pay for.

How many hours do you spend "fixing them" (new acid? New lead? what)?
And is your time worth $0/hr? vs going and at least getting a boat
battery. new.
 
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