Solar power battery system for WRT54GS - Page 2

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Re: Solar power battery system for WRT54GS



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We have a solution for the frog problem.

http://www.LearnByDestroying.com/k6bj/K6BJ%20Repeater/2m%20duplexer2.jpg
The little green effigy on the left is "Kermit the Frog".  We
threatened to sacrifice Kermit if the frogs misbehaved.  

All of my outdoor sites are near heavily traveled hiking trails or on
mountain top destinations for climbers.  Anything not bolted down or
near the base of the tower gets disappeared.  We also seem to have a
class of hikers and climbers that fail to appreciate technology and go
to great lengths to destroy anything not deemed "natural".  The
Coleman ice chest might work for protected or fenced installation, but
not out in the open.

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Grid power is nice.  Dumb 4th hand story.  I'm sure I've scramble the
details somewhere.  

Mountain top radio site wanted to expand onto an adjacent hilltop.
PG&E wanted about $50,000 to install 4 phone poles and provide
service.  Estimated electrical work about $15,000 mostly travel time
due to the remote location.  Connection fee was about $2,000.  I'm not
sure of the dollar amounts but they're in the ballpark.  USFS and CDF
were not going to allow buried power or creative underground conduit
power wiring.  Solar power was possible but it appeared to be a
continuous loss during winter.  The size of the panels required were
larger than the building roof or marginal southern exposure.

So, the sneaky owner installed a hydraulic system.  2000 ft of dual
hydraulic hose between buildings was snuck in as part of the "signal
wire" system.  I don't know the hose types or sizes.  A pump sends the
hydraulic fluid to the remote site, where a generator converts it to
sufficient electricity to run the remote site.  Bernoulli friction
losses were horrible but not so much that something would burn or
burst.  Overall efficiency was about 20% or less with 100 watts
delivered from the generator.  That was enough to keep the remote
batteries up when solar was lacking.  It only runs at night during
overcast days.

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It's really easy to overcharge a car battery.  However, I've found
that most automobile batteries, running in stationary service, simply
sulfidate badly, short, and die from running the battery down below
the 75% capacity mark.  Some type of low battery indicator, alarm, or
disconnect would be helpful to protect the battery.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


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OMG!  Couldn't they do anything with a few amps at (say) 50 volts DC
on those "signal" wires?  8*)

Re: Solar power battery system for WRT54GS



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Worse.  There were also two #6(?)AWG wires in the signal conduit
bundle that were also snuck in as part of the "signaling" bundle.  I
think what happened was that the insurance company conducted a
physical inspection after one of the other buildings had an electrical
fire and made sure there was nothing risky in any of the other
buildings.  There may also have been some EMI generated by the charger
current and picked up by 2000ft of 50 pair telco bundle.  I don't have
the details but was assured that it was impossible to supply power
through the comm/signal conduit.  I haven't actually seen this
hydraulic abomination but have been assured by others that it does
actually function.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


Isn't the telco voltage ( 48V  DC) kosher to run without all the issues
associated with a high voltage power line?

BTW, you don't have to have PGE run your power. I've never seen
construction where PGE didn't run the power, but in theory you could
hire a contractor and PG&E inspects.

PG&E operates in a strange manner in that as far as I know, they are
the only contractors that also get to sign off on their own work. That
is, there are no futher inspections.

In regards to you other post, it is nit-picking, but if that box as a
switcher on the input, it's not really a LDO. I'm pretty sure LDO just
refers to linear circuits, though many switchers incorporate LDOs for
their own internal use, or on the output to remove some switching
ripple.


Jeff Liebermann wrote:
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Re: Solar power battery system for WRT54GS


miso@sushi.com hath wroth:

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Yes.  However, there's a total power limit on what can be considered
signal wire.  I don't have a copy of the NEC code handy to look it up.

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PG&E has to install the poles and run the wires on the poles.  The
utility drop from the end pole to the building has to be underground
and is always done by the building owner.  That's part of the $15,000
in electrical work.  The same work done on the ground would be about
1/2 of that.

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Yep.  Actually just about any utility district (water, road, telco,
CATV) can sign off their own work.  In theory, the county or state
have oversight.  In reality, they only act on complaints.

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You're right.  LDO is strictly an analog term.  Especially since it's
possible for a switcher to have a negative input to output voltage
drop, where the input voltage to the switcher is less than the output
voltage.  Sorry.



--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


miso@sushi.com hath wroth:

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The input cazapitor is inside the WRT54G.  It's a chip tantalum and
I'm unable to determine the rating.  Common voltages are 16V and 25V.
I haven't seen one blow up yet, so I'll guess it's 25V.

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Probably, but let's do a bit of thinking first.  This is suppose to be
an "isolated" location for one end of a bridge.  My crystal ball does
not envision someone sitting next to this device with a laptop.  My
crystal ball tells me that this will probably be used as a WDS
repeater, or one end of a data collection system.  If it's a WDS
repeater, then including the router section in the power drain is
required.  If it's one end of a data collector, then the router is
superfulous.  Therefore, a wireless access point would do for the data
collector application.

Just for fun, let's say someone built a solar powered WDS bridge based
on a laptop MiniPCI card and a PIC or Rabbit controller.  It's doable.
The controller draws next to nothing compared to the wi-fi card.

Ubiquiti Networks SuperRange5 802.11a 400mW
  Receive = 350ma  (1.16 watts)
  Xmit = 700 -> 1400ma  (2.3 -> 4.6 watts)
Ouch.  Ok, that's for a high power 5.6GHz card.

Senao EL-2511MP+ 802.11b only card.
  Receive = 180ma (0.6 watts)
  Xmit = 280ma (0.93 watts)
That's much better.

BCM94306MP - Broadcom IEEE 802.11b/g Wireless Internal Mini-PCI Card
  Receive = 350ma (1.15 watts)
  Xmit = 550ma max (1.8 watts)
Sorta in the middle.

Therefore, if you use a miniPCI radio, and a very simple controller,
methinks it could be done with about 2 watts average power consumption
or half of what the WRT54G consumes.

I'm not sure it's worth the effort.  It would be easy enough to
disable the ethernet switch part of the WRT54G.  The WAP54G might be a
better choice for a simple bridge radio.  The front panel LED's on the
WRT54G could be switched off.  The processor clock on the router part
could be slowed down without affecting the wireless section.  

There are companies that make low power wi-fi chipsets that target
PDA's and cell phones:
  http://www.nanoradio.com
  http://www.conexant.com/products/entry.jsp?id=900
While these chips suck only microwatts in standby, the burn the usual
0.5 to 1.0 watts when active.  In effect, they are very low standby
power, not very low operational power.

There are also chipsets that target Zigbee sensornets that could be
used for Wi-Fi.  

I blundered across this white paper from TI which explains why 802.11g
consumes less power than 802.11b (because the xmitter is powered on
for less time):
  http://focus.ti.com/lit/ml/sply006/sply006.pdf
Moral:  Don't run your solar powered repeater at low data rates.

I couldn't find anything with the features of a WRT54G that was
specifically designed for solar operation.

Article on building a solar power wi-fi data logger:
  http://www.circuitcellar.com/library/print/1104/Cyliax172 /
He uses a Compact Flash Wi-Fi card.
  Receive = 200ma (0.66 watts)
  Xmit = 300ma (1.0 watt)
A bit better than miniPCI but not much.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


Jeff Liebermann wrote:

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Yes, if it was actually generating 25 watts during the day. The 25W
ratings is based on the panel being in direct sunlight. You really want
a 50W panel to be safe. These cost about $250.

-50 watt panel
-55AH battery (fully charged when put into operation)
-5A controller

Depending on the time of year (longer, sunnier days, versus shorter
cloudier days), even this may not be enough.

It makes you really appreciate being on the grid, when you look at how
much it costs just to provide a continuous 5 watts of power!

I wonder what they're doing with all the solar powered call boxes that
are being removed from the roads (at least in California they are
increasing the distance between the call boxes due to the significant
reduction in usage as a result of most people having cell phones).

Re: Solar power battery system for WRT54GS



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Yep, y're correct.  25 watts is what's needed to replace the power
consumed by the WRT54G during 24 hours (88 watt-hrs) with about 3.0
hrs/day winter insolation.  The 3.0 hours is the "equivalent" direct
sunlight that a non-tracking flat plate collector would receive during
the winter[1].
  http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas /
You're correct that 25 watts is insufficient, but for a different
reason.  If the solar system only supplied enough energy to replace
what was consumed by the WRT54G, then the system would take forever to
replace any additional losses.  The battery simply would never catch
up and take forever to get to full charge.

That's where I found a screwup in my spreadsheet[2], in the
calculation for days to recharge under full load.  The calculation was
inverted.  Revised version at:
  http://802.11junk.com/jeffl/rf-calc/solar-repeater-207.xls
I'm was a bit optimistic at 4.5hrs/day for mid winter.  Changed to
3hrs/day.

Revised (and fixed) version specific to WRT54G at:
  http://802.11junk.com/jeffl/rf-calc/solar-wrt54g-v101.xls
Note that even with a 40 A-Hr battery and a 50 watt solar array, it
will still take about 3 days to fully charge the batteries under load
in mid winter.

[1]  It's really Kw-hr per square meter per day, based on 1000
Kw-hr/m^2/day.  The number "3" would be the same as 3000 Kw-hr/m^2/day
or 3 hrs of equivalent full sunlight per day.
  http://www.windsun.com/Solar_Basics/Solar_maps.htm

[2]  Can someone check the spreadsheet for me?  Every time I look at
it, I find mistakes.  I can't seem to check my own work.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


http://www.allelectronics.com/cgi-bin/item/SCN-2/search/DC_VOLTAGE_CONTROLLER_FOR_SOLAR_PANEL_.html

Would this be sufficient, given it's only listed as 4 amps?


FYI, this would be for use with a WRT54GS.  I have a number of them
(2.2 version, so they now have dd-wrt on them).

I'm now looking for appropriate enclosures, and debating antenna.   The
box that I need in the middle of a field to provide line of sight
between two other locations should be fine with it's original antenna,
but I'm not certain how well the original antenna will perform given
they'll be inside whatever enclosure the WRT54GS is in.


Re: Solar power battery system for WRT54GS


jamessmalljr@gmail.com hath wroth:

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http://www.stahlin.com
PVC and fiberglass NEMA enclosures.  Put the antenna inside.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


Any links to someplace whose website I can actually navigate?   The
main page had flash, and no way to get around it?   I didn't see any
reference to price or how to order from the main page.


Re: Solar power battery system for WRT54GS


On 1 Apr 2006 05:59:15 -0800, in alt.internet.wireless ,
jamessmalljr@gmail.com wrote:

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Why not navigate in - the flash is horrible, but the site can be
browsed w/  Firefox so...


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Me neither, I suspect you need to find a dealer or phone them up.
Mark McIntyre
--

Re: Solar power battery system for WRT54GS


jamessmalljr@gmail.com wrote:
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I missed what size you decided to get.
Most of the John Navas links were to bare panels.
The Harbor Freight link includes a mounting arrangement, cables, and a
couple of lights, with a poor power control box.
The Costco link to the Coleman/ICP link includes mounting, a charge
controller, and an AC inverter.

http://www.costco.com/Browse/Product.aspx?Prodid=11099458
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90599
The Harbor Freight review
http://www.northernmichigansolar.com


--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA  38.8,-122.5

Re: Solar power battery system for WRT54GS


jamessmalljr@gmail.com hath wroth:

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Yep.  The main page uses Flash to navigate.  Try:

http://www.stahlin.com/NonMetallicProducts.cfm?sublinkid=6&articleid=0&navid=1
Actually, I use the printed catalog.

This is the series that the local electrical supply house stocks:

http://www.stahlin.com/DisplaySelConfig.cfm?navid=1&sublinkid=6&familyid=3&configid=196
It's PVC, waterproof, and UV resistant.  Note that there are other
vendors of non-metallic electrical boxes.
  http://www.hoffmanonline.com
  http://www.hammonddirect.com
  http://www.hammfg.com
or for portable use:
  http://www.pelican.com

One gotcha with internal antennas in PVC boxes.  The active elements
for the antenna should be kept away from the sides and the lid. That's
because PVC is fairly transparent to 2.4GHz RF, but will detune the
antenna slightly.  You can sorta see the effect if you take a piece of
small diameter PVC tubing and slide it over a high gain omni antenna.
The resonant frequency goes down slightly.  I built a biquad inside a
PVC electrical box and ran into this problem.
  http://802.11junk.com/jeffl/antennas/biquad2/index.html
The effect should be much less with fiberglass boxes, but I haven't
tried those (yet).

Also, watch out for venting batteries.  Leak proof batteries are NOT
outgas proof.  Yo can demonstrate that to yourself by simply putting a
plastic bag around a common gel-cell and charging it.  Not only will
you eventually see some gas expansion, you'll also probably notice
droplets of liquid on the surface.  If you put the battery inside the
box, put it in a seperate sealed section and vent that section.
Otherwise, your expensive electronics will corrode.

Also, watch out for temperature problems.  They do get rather warm in
the sun.  The lack of ventillation means that small sources of heat
will tend to build up to rather high temperatures.  The WRT54G burns
about 4 watts.  That's tolerable for a small box.  Try to get some
conduction cooling to the outside, spread the heat out with a metal
plate, or give up and use a metal box with an outside antenna.

Assorted packaging attempts.
http://www.mavromatic.com/archives/000451
http://www.grynx.com/projects/all-weather-wi-lan-enclosure /
http://wireless.hackaday.com/entry/1234000730067498 /
http://socalfreenet.org (type "solar" into the search box)

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS



Some photos and ideas for creative outdoor packages:
  http://www.hyperlinktech.com/web/nema_enclosures_examples.php
They're not solar powered but it does give an idea of what can be
done.


--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Solar power battery system for WRT54GS


miso@sushi.com wrote:
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About 6W


Bad idea, since the high volume solar panels and batteries are all 12
volts. You don't want to be wasting any power through voltage regulators
or DC-DC converters.


Re: Solar power battery system for WRT54GS


Technically, you are using a DC/DC, just that it is built into the
Linksys router.

Without a manual (what kind of a company doesn't put manuals on-line in
the 21st century), I can't comment on how well the built-in DC/DC of
the linksys works. What voltage wall wart is supplied with it?

SMS wrote:
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Re: Solar power battery system for WRT54GS


miso@sushi.com wrote:
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True.


You mean schematics?  What company puts schematics online these days?

The Linksys is usually supplied with a 12V wall-wart, though IIRC
they've been shipped with 5V wall-warts in the past.  The WRTs are
pretty forgiving of input voltage, which makes the ideal for battery
power.

Re: Solar power battery system for WRT54GS


No, just a manual. There was no on-line documentation regarding the
voltage of the wall wart.

William P.N. Smith wrote:
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Re: Solar power battery system for WRT54GS


miso@sushi.com top-posted:
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That's because it can (and occasionally does) vary, depending on what
Linksys can get good pricing on.  And it doesn't matter, anything from
5-12V will work, and there's a bit of margin on either side as well.

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