solar power for small server, router, and network equipment

 Hello,

I'm sure I'll get flamed by people for not searching enough for the
answer, but luckily for me, there are at least a few of you out that
that care enough to overlook that and help me anyways.

I want to "green up" my home network.  I have a desktop server that
runs 24x7 as well as an access point, router, switch and DSL modem.  I
also have an HP LaserJet 4100 that is always on (but in some sort of
"standby" mode most of the time).  My computer room is in the
basement, which helps with keeping things cool, and it is also on the
west side of my house (which gets the most direct sunlight since I
live in Kansas).

I'd like to hook up a solar panel outside my house and charge up some
batteries to power all of this equipment, as well as give me some
failover in case the power is out (this is not as important as saving
the energy, just a convenience).

I've done some reading, and I know that I'll need to have much more
electrical engineering experience to do this right, but I want to try
anyhow.  Is there a website that has good information on this, or can
anybody give me any tips as to what sort of solar panels to use,
batteries to buy, etc.

Thanks
Brandon Riffel

  On Tue, 17 Jul 2007 19:25:25 -0700, Brandon Riffel


This should get you started
http://www.homepower.com/files/promised/loadcalc.pdf  It's best to
measure your loads rather than estimate them. One of these will make
the job a snap http://www.supermediastore.com/kilwateldet1.html . The
solar hardware is probably going to cost a lot more than you expected.
For example, your total load might be about 150W. To power that 24-7
with 5 hours per day full-sun equivalent, you'd need about $5k of PV
and perhaps another grand (ball park minimum) for batteries and an
inverter.

Wayne

 On Tue, 17 Jul 2007 19:25:25 -0700, Brandon Riffel


First thing to do is realize that the more you can conserve power the
less you'll have to generate.  Unless you never sleep, there isn't
much point leaving equipment on 24-7.  I know, it is easier, but when
you generate your own power there is really no point in having to make
a third more than you need.  

Next you'll have to figure out how many cloudy days in a row you want
to be able to survive.  Get yourself a meter (they are cheap) and
figure out how much power you really need for the systems.  Multiply
the number of days by the power needed, double it since you don't want
to drop a set of batteries below 50% charge and you'll be able to
figure out how much battery power you'll need.  Once you have that you
can figure how you'll have to wire the batteries and what voltage
you'll want to use.  I'd prefer to keep it to one series string of
batteries if possible, but others will have differing opinions.  Once
you know all that it is time to find a charge controller, inverter and
panels.  At any point in the process feel free to come back here with
questions.  

 

the laserjet may be a problem.  They use a lot of power and also usually
require a true sine wave inverter -- which is spendy.  Your comp probably
won't need the sine wave inverter if you have a good PSU.

If you kept the laserjet on home power you could probably run the rest
pretty easy -- the printer will probably nearly double the energy
requirements and quadrouple what you'll need to spend for an inverter.

my 02 cents

 

z wrote:


I totally agree on that point. It simply doesn't make any sense to attempt to
power certain loads from local low power generation.

In fact, taking that further, you could say that the all of the OP's PC etc
equipment ought to stay on mains power, since the mains is best at dealing with
'difficult' less than unity power factor loads, and the solar cell output would
best be used to power less 'tricky' loads.

Take that further still and if the OP used thermal solar for water heating
instead of buying expensive low efficiency PV generation ( about 10-14%
efficient) he could reduce his overall energy requirements hugely.

Powering the PC from solar PV frankly falls into the category of (expensive and
not actually very 'green') the worst kind gesture politics actually. There are
vastly better and greener things to do with both one's money and the world's
resources.

Graham