[mythtv-users] Proposed future power saving networked configuration (0.22 in mind)

Jon Bishop jon.the.wise.gdrive at gmail.com
Tue Mar 10 08:59:48 UTC 2009


On Feb 18, 2009, at 7:42 PM, Michael T. Dean wrote:

> On 02/18/2009 10:40 AM, Jon Bishop wrote:
>> On Feb 18, 2009, at 4:58 AM, Chris Pinkham wrote:
>>> Sure, it will take me years to save enough power to pay for my
>>> programming time to add this feature, but if it's $5-10 less that  
>>> I'm
>>> paying the power company each month it's worth it now.
>> But it's worth it... them greedy utilities!  ... Well, actually, I
>> believe that as a people, globally, we need to stop depending so much
>> on utilities and corporate conglomerates and produce more of our own
>> energy. Electricity is so easy to make, and there's so many ways to
>> make it... it's just a shame that the inverters to take it from
>> batteries and make it a nice pretty 60hz (or 50hz) sine wave are so
>> darn expensive.
>
> Actually, taking it to a nice pretty sine wave would be a travesty.
> Computers run on DC power, so if you attach your solar/wind/home- 
> nuclear
> generator to batteries, then attach an inverter to the batteries to  
> make
> AC, then feed that AC to the computer PSU, it will take the AC and  
> turn
> it back into DC...  So, you incur an efficiency loss going from DC- 
> >AC,
> then compound the loss with a second efficiency loss going from AC- 
> >DC.

Yea, for the computer.... but the rest of the stuff in the house.... I  
will keep that in mind though. I've seen lots of off grid setups wired  
with both AC and DC - run all the lights and anything else you can off  
DC, and everything that must off ac.

<snip power supply links>

> Then, once you get a working setup, write up a page on the wiki/your
> blog/some forum and post a link here so I can do the same with some  
> nice
> Concorde Lifeline batteries ( http://www.batteryweb.com/ 
> lifeline.cfm ).
> It's charging the batteries that has me stumped, so far.

Charging batteries is easy - the most obvious answer being solar  
panels - but you can make electricity very easily. Windmills are  
common... you could convert a bicycle into a generator. There's lots  
of ways to manually make power. Micro-Hydro is becoming popular in  
areas that have from slow moving year round creeks up to large rivers  
available to tap into. You could even make a methane powered steam  
generator.

http://www.windstuffnow.com/main/
http://www.otherpower.com/
http://www.microhydropower.net/
http://www.green-trust.org/methane.htm

I intend to build a VAWT at some point sooner or later, but it keeps  
on ending up being later. Otherpower is a very good resource for home  
brew electricity.

As for batteries, I am a member of the EV mailing list, and they're  
talking about batteries ALL the time -

Lead Acid is the cheapest kind of battery in terms cost per Ah, but is  
also the biggest and heaviest battery technology (well, unless you go  
back to Henry Fords Nickel-Iron batteries). Lithium is expensive and  
hasn't been ironed out yet, but recently there was a discussion about  
the viability of using molten salt batteries, that lead me to do some  
research on them. These would seem ideal for something like a house.  
They have higher energy density, weigh less, and supposedly can handle  
more cycles. There's a downside - if you leave them unused for any  
period of time, they freeze... which makes them less than perfect for  
someone that drives less than every day, but is moot in a house where  
they are being constantly charged/discharged. The batteries themselves  
keep a nice toasty internal temperature of 300C. There are actually  
quite a few power companies starting to use these for load balancing. http://www.aep.com/newsroom/newsreleases/?Id=1397 
  Unfortunately, I have yet to find someone that will sell me these  
kind of batteries. I, apparently, am too small a fish at this time.

So, the next best thing is to find some old BB600 NiCad batteries  
(find them as surplus airplane batteries). After that you start  
looking into more expensive chemistries that yield little return (in  
terms of cost) for a home application - mostly just lighter and  
smaller - which isn't *as* important in a stationary application.  
Also, the battery life can't be guaranteed - I've heard of using  
NiCads for 30 years and still being nearly new in terms of charge  
density. Lead Acids sulphate over time (build up of crystals on the  
lead plates) which leads to decreased storage, but is mostly  
reversible, NiMH appear to have a good number of cycles, but finding a  
large format battery is near impossible, and everything else that's  
out is basically too 'new' to have really good service life data.

> (I'm fully expecting you'll actually do this as I just shelled out  
> for 4
> more 80 PLUS PSU's to decrease my power usage, so you'll figure out  
> how
> to do the project I wanted to do instead now that I've already  
> invested
> a bunch in AC->DC PSU's.  See
> http://www.gossamer-threads.com/lists/mythtv/users/371460#371460 to  
> see
> how the new PSU's are saving me $1.5/mo each at $0.10/kWh.)

I intend to work on portions of this, but hope my links will help you  
on your journey. I really want to feel less dependent on the whims of  
the idiots that seem to be in charge at any point in time - if I can  
produce my own electricity, and capture and filter my own water (which  
will in turn allow me to grow my own food) I will be a little better  
off in the future, when we stop warring for oil and start warring for  
water and power (ooh, creepy scenes from Tank Girl come to mind, of  
course not the 'roos)

And somehow I got waaaay off topic (I tend to do that when people get  
me talking about something interesting like this!) And now I will go.  
Hope this helps some though.

~Jon


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