Re: A different approach to saving power with solar panels.

[Simon Haslam <simon_haslam@xxxxxxxxxxx>]

I had a similar kind of debate a while back on the navitron.org.uk
forum. A=
pparently "common" UPS's (from APC etc) operate in a
"direct" mode whereby =
under normal conditions the AC is used to power the equipment directly
(alb=
eit with some mains conditioning), and not via the 12V batteries. You can
g=
et "indirect" UPS's where mains is converted to 12V (or whatever)
and then =
converted back to 220/240V. Also there were debates about whether a normal
=
UPS would be capable of running for long periods on batteries without
early=
component failure (as compared to solar inverters which are designed for t=
he task). Finally working inside the UPS with high voltages would mean
you'=
d need to be very careful about safety.

Your second approach sounds easier and more efficient (as it saves the
conv=
ersion from 12V to 220/240V to 5V or whatever). It would just be a solar
in=
stallation charging a battery bank which has been tried and tested for
year=
s. You'd need to work out what devices you could most easily make power
sup=
plies for (ideally choose several of the same DC input voltage). I haven't
=
looked this up, but can imagine some green people will have done this kind
=
of thing before.


Simon

--- On Mon, 31/5/10, Neil Wrightson <neilw@xxxxxxx> wrote:

From: Neil Wrightson <neilw@xxxxxxx>
Subject: [ukha_d] A different approach to saving power with solar panels.
To: ukha_d@xxxxxxx
Date: Monday, 31 May, 2010, 10:44







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Hi All,

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Here in Australia the government is encouraging us to install solar systems

either electrical and or hot water.

To this end they are subsidizing the cost but it is still quite a large
som=
e

of money.

I.e. $10,000 over ten years. By then the cells are probably cactus and you

put your hand into your pocket and start again.

=20

These systems use inverters that feed straight back into the electrical

grid. So no batteries are used.

=20

I'm very much a handyman, so I have no problems in installing my own solar

panels (that I can buy at wholesale prices) but trying to get the rebate on

these and having a licensed electrician connect it to the grid, could be a

problem.

=20

So how could I save a few electrical dollars and satisfy my geeky urge to

have something like this. Hmmm.

=20

I, like many of you have a Node0. Mine has the usual array of UPS's
servers=
,

switches, video overlays, I/O, callerid, cameras etc etc.

=20

So basically, what I was thinking was putting some solar panels onto the

roof and at least power my Node0 for some of the day.

Make me feel warm inside that I'm doing my green bit ;-)    (Switching half

of it OFF would be greener but not as much fun)

=20

Option 1

So considering that Node0 has a 1000VA UPS with additional battery packs.

I thought I could monitor the solar panels and when there is enough power

available switch the incoming mains power to the UPS off and feed the UPS

from the Solar panel inverter.=20

When the light starts to fail, say mid afternoon and the panels don't work

as well, switch the incoming UPS back to mains power.

Twice a day the UPS would see the power turned ON/OFF/ON for say a 30
secon=
d

change over period.

Apart from that, Node0 equipment would know no differently.

=20

Option 2

Feed the 12/24VDC connection from the solar panels to a battery and
directl=
y

power the lower voltage stuff in Node0.

=20

=20

Has anybody thought of trying to do this kind of thing?

=20



Regards,=20



Neil Wrightson.=20

N.W.Electronics=20

ABN 76 768 513 867=20

Embedded Controllers and Home Automation Products=20

Skype : Neil_Wrightson=20

Web     : www.nwe.net.au=20



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