Posted by Martin Brown on October 29, 2009, 1:46 pm
Paul Keinanen wrote:
> On Thu, 29 Oct 2009 08:12:41 -0400, "vaughn"
>
>>> For a laptop, printer and a couple of 15 watt compact florescent lights?
>>> Hardly a huge expense, with 1000watt inverters $00.00 on ebay, a couple
>>> of Sams' club deep cycle batteries ?
>> Actually for system you don't really need inverters at all. I use
>> 12-volt compact florescent lamps,
>
> Which definitely contains an inverter, thus, adding cost.
Although they are cheaply mass produced as emergency standby lights.
And pure solid state LED based units are still more expensive.
>
>> I use the lamps out in my yard, and my in-home 12-volt wiring
>> system is slowly growing.
>
> This is a good strategy if the 12 V system total cost is less than the
> cost of more common 120 V (US) or 230 V (Europe) systems added with
> the inverter cost.
Although you really need to pay attention to the current flowing in a
low voltage DC wiring system. It takes a lot more of a percentage when
you drop half a volt off 12v than the same drop on 120 or 240v.
And to deliver the same power into the load takes 10x or 20x the current
on a 12v service. Useful if you are off grid but not so good in winter
at my latitude. Not enough winter sun to keep things topped up.
Wind power is a bit better in that respect if you have the space.
Regards,
Martin Brown
Posted by Dirk Bruere at NeoPax on October 29, 2009, 5:55 pm
vaughn wrote:
>> For a laptop, printer and a couple of 15 watt compact florescent lights?
>> Hardly a huge expense, with 1000watt inverters $00.00 on ebay, a couple
>> of Sams' club deep cycle batteries ?
>
> Actually for system you don't really need inverters at all. I use
> 12-volt compact florescent lamps, and 12 volt adapters are available for
> laptops. I use the lamps out in my yard, and my in-home 12-volt wiring
> system is slowly growing.
Does a low voltage DC house supply make sense?
It's looking like it for lighting.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show
Posted by vaughn on October 29, 2009, 7:24 pm
> Does a low voltage DC house supply make sense?
> It's looking like it for lighting.
My system is mostly for lighting, with possibly a laptop and a portable
TV thrown in during power failures. The "40-watt-equiv" 12 volt CFL's that
I use draw 1 amp each. So far, the most I have on one circuit is 2 of them.
For minimum voltage drop, I wire my interior circuits with #10 THHN wire.
Vaughn
Posted by Dirk Bruere at NeoPax on October 29, 2009, 8:25 pm
vaughn wrote:
>> Does a low voltage DC house supply make sense?
>> It's looking like it for lighting.
>
> My system is mostly for lighting, with possibly a laptop and a portable
> TV thrown in during power failures. The "40-watt-equiv" 12 volt CFL's that
> I use draw 1 amp each. So far, the most I have on one circuit is 2 of them.
> For minimum voltage drop, I wire my interior circuits with #10 THHN wire.
How would one go about powering a laptop from a 12VDC supply? DC-DC
converter? The only things I would likely power from PV would be lights,
computers (laptops) and a fridge.
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show
Posted by vaughn on October 29, 2009, 9:16 pm
> How would one go about powering a laptop from a 12VDC supply? DC-DC
> converter?
Google the term "laptop auto adapter" for zillions of returns like this:
http://www.powerstream.com/ADC.htm
>The only things I would likely power from PV would be lights, computers
>(laptops) and a fridge.
My 'fridge does not like my square wave inverter (some do, some don't).
Also remember that your defrost heaters can take well over 1,000 watts. My
present disaster plan is to run my refrigerator only when my generator is
running.
Vaughn
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>
>>> For a laptop, printer and a couple of 15 watt compact florescent lights?
>>> Hardly a huge expense, with 1000watt inverters $00.00 on ebay, a couple
>>> of Sams' club deep cycle batteries ?
>> Actually for system you don't really need inverters at all. I use
>> 12-volt compact florescent lamps,
>
> Which definitely contains an inverter, thus, adding cost.