Home Power System

Welcome to the Precious Metals Bug Forums

Welcome to the PMBug forums - a watering hole for folks interested in gold, silver, precious metals, sound money, investing, market and economic news, central bank monetary policies, politics and more. You can visit the forum page to see the list of forum nodes (categories/rooms) for topics.

Please have a look around and if you like what you see, please consider registering an account and joining the discussions. When you register an account and log in, you may enjoy additional benefits including no ads, market data/charts, access to trade/barter with the community and much more. Registering an account is free - you have nothing to lose!

benjamen

Yellow Jacket
Messages
1,574
Reaction score
9
Points
0
Location
Migratory
For those of us that are not experts in the field, here is a thread dedicated to home power systems. Hopefully our resident mad scientist chimes in on the subject.
:cheers:

General article:
http://www.survivalblog.com/2013/07/home-power-systems-batteries-by-lko.html

Choosing the best battery:
http://www.homepower.com/articles/solar-electricity/equipment-products/choosing-best-batteries

Battery university:
http://batteryuniversity.com/learn/

Batteries for alternative energy set ups:
http://www.altenergymag.com/emagazine.php?art_id=1513

Magazine on the subject:
http://www.homepower.com/

Wind power:
http://www.makeenergynow.com/home-wind-power-systems/
 
Obviously, I have some odd mix of opinion, experience, and philosophy here, having done this (and made a few mistakes along the way), and there's a lot to know.

Having been burned on the "cheap stuff", I no longer even consider it. YMMV, as well as your opinion. I avoid the "puff sheet" mags on the topic, as they rarely have more than gee-whiz info, just press release kind of stuff. I'm much more interested in the vendors, what they have and recommend - especially if they also install - they know what makes customers happy better than anyone - even if you're going to do the work yourself - and make a bunch of the parts (racks, sheds for batteries, etc), it's nice to talk to those who have been there and done that over a period of years, rather than some johnny come lately.

I've been using Xantrex for the electronics almost exclusively, the stuff is built, if anything, better than things NASA wants to put in orbit, or the Navy under the poles (old cold war joke). This outfit used to be called "Trace", but has been sold to Schneider, and is now Xantrex. A little pricey - but only once. I've got some of their gear now 30 years old and never so much as a burp.

Solar controllers - these are high efficiency DC switching supplies that "match" the output of the panels to the batteries - no matter where the voltages sit, within reason, and are good for about 30% additional power over just hooking say, a 24v nominal panel to a 24v nominal battery pack. Way worth it - they outperform when you need it most, dim light and low batteries. This is called "maximum power point tracking".
Solar panels have a higher max-power voltage when cold (in winter or just in the morning), just when your batteries are at their lowest point - the DC-DC switcher adjusts the "turns ratio" automatically to extract the most power under that situation.
Think - if you need a few hundred feet of wire - would you rather be buying #2 or larger, or #10? There's a lot of money in that copper in a real system.

They also allow you to run higher panel voltages so you can save big on wire sizing.
I used to think that was bad - things in series fail when just one fails, in general, but the truth is, after switching to HV/series connection, it's so much better it ain't funny.
Part of the reason for that, I suspect, is that the newer panels (250w class) already have a couple strings of cells in parallel, so shade on just one cell still lets the panel perform pretty darn well. I'm running most of mine at 90v nominal, into a 24 volt battery system. If you want to go big - use a 48v battery system, it's less amps in and out for the same power (half the amps - cheaper wire, less troubles).

I have NOT found trackers or other "gimmicks" to be worth it, just something else that tends to need fixing just when you need it most, and they are confused on cloudy days, of which there are all too many. One thing about solar - you'll become very sensitive to what the weather is doing, and perhaps adapt a bit on your power use depending - and maybe adapt a lot.

After years of living with L16's - a good choice for learners as they point out above, since they are "light" and "cheap" and you WILL likely ruin your first batch if you don't pay enough attention, I'm fully in the "industrial" camp now - Rolls-Surrette batteries come with a 20+ year warranty that means it. With extreme care and some tricks, 8-10 years is end of life on L16's. You can work out the costs...the good stuff is cheaper in TCO. Note, if you use the Xantrex electronics, it goes a long way toward making batteries live longer with the 3 stage charging, and warnings when you're about to run them too far down (including not letting you really run them flat - it shuts off).

I go with the philosophy that the more coming in, the less everything else matters, so I went space-limited with panels - as many as I could fit. The upside of this is that even when it's kind of dark and rainy, I get about a kilowatt out of mine...enough to run my home in a slightly hunkered down mode (in that mode, I draw ~300w, most of that this computer and a couple small DC fans for home ventilation). This is much more practical than it used to be, as panels are super cheap ~$1/watt, compared to when I started - $6/watt.

I really don't run anything off the batteries direct, and haven't for a long time. There was a time I was running 12v, and using some auto accessories. These are all dreadfully ineficient compared to good 120v (or 240v) stuff, and the inverters are plenty efficient on a decent sized system (20w tare load), it's just not worth it to fool with that unless you're doing things like using mil surp hydraulic power packs and such (in which case, the required wire size kills you and you don't save anyway). OK, I do run a couple things straight off batteries, I have LED night-lights here, like a string of Christmas bulbs run around the cieling upstairs, and a few higher power ones downstairs to blind an intruder as part of my defense system.

Instead, I run 3 inverters in this two-building system. I have an old DR2435 square wave inverter that makes the motors in my machine shop sing and put out more torque than on sine waves, and two 4kw (nominal, they'll do 70kw for a few minutes under peak loads) for everything else - I use one primarily for 240v stuff - car charging and welding, and a 120v one for the rest. All 3 can be hooked to the grid, or a backup generator, or both and do wondrous things like be a great battery charger, or grid tie (load shaving, only using the grid when rates are low if you get a TOU plan, and so on).

You WILL need a backup generator of some sort, and you should be able to run it wide open (don't oversize here) to get the best BSFC out of it. I use a tiny Honda inverter-generator or my Volt (with an inverter in it) for lower power sustaining backup, as my 3300w one is currently "down". Yes, you will have backups on your backups, all hot and ready to go if you want my magic "infinite 9's - no unplanned failures ever - performance. These days that includes a PM schedule on the generators to make sure they don't sit so long as to be hard to start when needed.

I got a little bit of serendipity out of the latest upgrade. Since my panels sit away from the roof a bit (I did my own racks), they shade the roof and keep it cool, which reduces the need for AC (big load, bad to need) in summer.

I did a bit of a "dirty sneaky trick" as well - since I have panels at two angles - one ideal for summer, the other winter - I can "over use" my controllers, since the sun is never at the ideal angle for both at once in a given lashup - it will have some ideal for whatever season, and all putting out best they can in diffuse light, when you need it most, but still stay under the controller ratings (the controller will protect themselves at some max amps, but that's not a problem - it means you have more than you need anyway).

You will also become an expert in judging battery condition reading volts versus net amps to the pack (you may have to install a net amp meter, I did). That way you'll know how to adapt to what nature is giving you without putting extra wear on them, and since they aren't cheap and are the only thing that fails in general - it matters.

You will also lean to conserve - even now, it's far cheaper to be efficient than to just put up more gear. Everything I own is on a power strip - and not the kind of strip that has "surge protection" which wastes a couple watts just sitting there off. You'd be shocked at how many things are "vampire loads" that draw significant power even when apparently turned off - anything with a remote, most things with power noise filters...it can come to 30w per thing. All those little clocks in microwaves, VCRs and always-on network connections - you have to decide what you want on at all times and be EXTREMELY picky about that. I have one always-on DC fan, about 200 cfm, that pushes air into the basement, and some LED nightlights. That's it for always-on, for example.

There's a lot more here on my alt-energy forum: http://www.coultersmithing.com/forums/viewforum.php?f=48&sid=742bb3e1e6f55b42563be4e72cf62e36

But of course, I'll gladly answer any questions. A point I'd make is that if you want to do this kind of thing - get going now, the learning curve is longer than you'd think, and you won't be able to do it well at the last minute. While great improvements have been made, it's still not fully automatic - being the power company IS a job, even if it's not too much work - the problem is, the work always needs to happen at inconvenient times. Better to find that out, and the preps/workarounds to make it better before you really depend on it.
 
As I plan to purchase a new piece of property to live on within the next couple of years, I turn back to this idea of a home power system.

Electricity prices in the U.S. are marching to historic highs.
http://www.cnsnews.com/news/article/terence-p-jeffrey/price-electricity-hit-record-october-42-decade
"The price of electricity hit a record for the month of October, according to data released Wednesday by the Bureau of Labor Statistics. That made October the eleventh straight month when the average price of electricity hit or matched the record level for that month."

Due to new EPA regulations, 35% (204 out of 580) of all U.S. coal power plants are slotted to close in the next five years. I shudder to think of what this is going to the do the cost of electricity!

http://www.environmentalleader.com/...4-coal-power-plants-to-close-in-next-5-years/
http://www.americaspower.org/sites/default/files/Coal_Unit_Retirements_Sept_2012.pdf

I may be bugging Mr. Fusor for more information soon!
 
This is a wet dream for Obama. He will have destroyed what remains of he middle class after Obamacare.
 
As I plan to purchase a new piece of property to live on within the next couple of years, I turn back to this idea of a home power system.

My dream would be a fast flowing stream or river running through the land ...

but if you dont mind the environmental paperwork then you could buy an old coal mine and quietly rework the spoil heaps

Here in blighty weve still got ancient mining rights to dig for coal in the Forest of Dean.

http://www.clearwellcaves.com/freemining.html

and theres more than a few still rummaging around the old coal workings in Wales.
 
Even better is a source of water with some drop or pressure on it. But that has maintenance issues, at least with the ones I've worked on. Flash floods carry all sorts of junk into your system. If you try to screen the big pieces out, they clog the filter - you have an active maintenance requirement, much more than with solar.
On the other hand, if you live as far north as UK, then solar isn't as great, due to low sun angles - "full sun" there has to go through more air, which makes it less, it doesn't stay up as long, and all that.

The ideal case would have all 3 - sun, water, wind. Then almost no matter what the weather, you'd be smiling...

It takes more water than you think to make enough power to be worth all the work. To get 500w or so, you need about a horsepower's worth of pound-feet/second through your turbine (which is actually an optimistic number, assuming a pretty efficient turbine/generator setup).
This: http://en.wikipedia.org/wiki/Horsepower shows you need about 33,000 lb/ft/min per HP.
That's a *lot* of water if the drop isn't far.

I tried this on a small stream here and with 5 ft drop (built a small dam), got about 50w, and it basically wasn't worth it to push that back half a km to the house and keep digging the sticks out of the banki turbine I built. It's defunct now, I've even pulled down the wiring, since the sun and weather were starting to make it useless. Glad I never invested in that much weather proof wire, as that stuff is really expensive, and not truly weather proof anyway (good for burial, though).
 
Back
Top Bottom