OFF GRID POWER; various thoughts on...

Started by MountainDon, January 13, 2009, 02:18:39 AM

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joeshmoe

Quote from: Dave Sparks on September 22, 2015, 09:55:11 AM
Consider moving to the Southwest US if you do not want to use a generator. It really make sense if that is important to you. Pick a place in the foothills somewhere with 15" of rain or more, a blue oak woodland or similar, and property that is wide open to the sun or on the right side of the mountain.

I lived in central Arizona and northern New Mexico for a few years each. Liked both areas, especially New Mexico. Loved the mountains and the huge swaths of public land. The downsides I noticed were expensive land, particularly if water was available, and struggling schools in more rural areas. I've got a young child so that limits the places I can consider. I'm not opposed to having a generator as a backup. I just wouldn't want to rely on it constantly.

MountainDon

Yes, we love our sunshine!   :)   And very little snow to shovel. Mostly I don't.
Just because something has been done and has not failed, doesn't mean it is good design.


rick91351

Quote from: MountainDon on September 22, 2015, 01:25:03 PM
Yes, we love our sunshine!   :)   And very little snow to shovel. Mostly I don't.

Up here in the great white north we just look at it as our gym routine.   ;)   Me thinks your missing out on a great deal!    rofl
Proverbs 24:3-5 Through wisdom is an house builded; an by understanding it is established.  4 And by knowledge shall the chambers be filled with all precious and pleasant riches.  5 A wise man is strong; yea, a man of knowledge increaseth strength.

rick91351

Quote from: MountainDon on September 22, 2015, 01:25:03 PM
Yes, we love our sunshine!   :)   And very little snow to shovel. Mostly I don't.

By the way when it does stop snowing we do have brilliant sunshine  8)   in between snow storms and snow squalls........
Proverbs 24:3-5 Through wisdom is an house builded; an by understanding it is established.  4 And by knowledge shall the chambers be filled with all precious and pleasant riches.  5 A wise man is strong; yea, a man of knowledge increaseth strength.

MountainDon

I lived in the great white frozen north for most of the first 38 years, 10 months, 29 days of my life.  Latitude 49.8994° N. 

I think I have the best deal where I am now. Latitude 35.2861° N   1010 miles further south   ;D


The northern place actually has more days rated as sunny (316) than where we are now (278).  However, the days down here have more hours of sunshine, and less difference between hours of summer and winter sunshine. Back north the winter cold combined with the short days get to be a real drag. At least for me.
Just because something has been done and has not failed, doesn't mean it is good design.


rick91351

Quote from: MountainDon on September 22, 2015, 02:18:57 PM
I lived in the great white frozen north for most of the first 38 years, 10 months, 29 days of my life.  Latitude 49.8994° N. 

I think I have the best deal where I am now. Latitude 35.2861° N   1010 miles further south   ;D


The northern place actually has more days rated as sunny (316) than where we are now (278).  However, the days down here have more hours of sunshine, and less difference between hours of summer and winter sunshine. Back north the winter cold combined with the short days get to be a real drag. At least for me.


We are not very far from the 45th so I understand completely the short day cycle but so love the long day thing.....  One reason I wanted to move to the mountains was the lack of inversion (fog),  Boise valley can get bad - very bad and dreary especially on those really short day light days.     
Proverbs 24:3-5 Through wisdom is an house builded; an by understanding it is established.  4 And by knowledge shall the chambers be filled with all precious and pleasant riches.  5 A wise man is strong; yea, a man of knowledge increaseth strength.

kenhill

61 degrees and got 4 inches of snow last night.  Temp is 42 and sunny now!

Triathlete

It seems as though the amounts of snow vary widely from year to year here in Canada.  This year we got a few inches and then it rains.  Right across Canada it has been quite warm but extremely gloomy this winter so far, so there has been little to no snow on the ground.

Btw, I crunched the numbers for power use again on an off-grid solar system.  It's hard for me to live on anything less than about 4000 watts a day and to go off-grid the costs with no generator seem exorbitant and the project exceedingly large.  Depressing.

OlJarhead

Living off grid really does mean giving up a lot of power hungry items or learning to use them sparingly when the gen is running.  Unless of course you have a ton of money to spend ;)

I think it's more about independence and sustainability vs cost savings.


MountainDon

4 KwH a day is not bad for use.  That's about a third of what we use at home and about 3 times as much as we use at our cabin. Calls for a healthy sized battery bank though.
Just because something has been done and has not failed, doesn't mean it is good design.

Dave Sparks

 4KWH is what most offgrid homes use when conserving in my opinion. Cabins a little less.  Hard to do this up north without lot's of generator use. The other way to bring this number down is a propane refrigerator or something that gets away from an electric  refrigerator cycling. I have a client in Alaska doing this with 12 KW of solar and very little generator use. Anything can be done if the strategy is right.
"we go where the power lines don't"

DaveOrr

Yes, the more you can reduce your electrical dependence the easier it will be to run off grid mostly solar.
I'm planning to run propane fridge, stove, wall heater and main heat will be a Wiseway pellet stove.
Pretty much the biggest electrical draws will be my espresso machine and microwave.
Lighting is going to be 100% LED as well.
TV and SAT dish are the only other real draws on the system.
Can't miss my hockey games just because I'm in the bush now can I?   ;D
Dave's Arctic Cabin: www.anglersparadise.ca

flyingvan

Find what you love and let it kill you.

Redoverfarm

Water Well pump?   

I thought I was ahead of the consumption when I installed a Grundfos 240v pump which is a slow start using 9.8 amps.  No one ever mentioned that to attain that 9.8 amps of AC it would take 31 amps of DC.  Biggest consumption is the flush toilet.  If I could just convince the ladies to hit the woods.  Nope not going to happen.   ;)


garyc

Quote from: Redoverfarm on December 10, 2015, 01:02:19 PM
Water Well pump?   

I thought I was ahead of the consumption when I installed a Grundfos 240v pump which is a slow start using 9.8 amps.  No one ever mentioned that to attain that 9.8 amps of AC it would take 31 amps of DC.  Biggest consumption is the flush toilet.  If I could just convince the ladies to hit the woods.  Nope not going to happen.   ;)

If it's yellow let it mellow if it's brown flush it down.
If it wasn't for bad luck . I would 't have any luck at all.

MountainDon

Something that could help some with the power use would be a dual flush mechanism; low volume for #1 and higher volume for #2.  We have a couple of the kits sold by MJSI in our 2 toilets. The volume is user adjustable. We have one with the button and one with the lever control. The lever type requires less finger force that the button. But the button best suited the one tank with a side mount control.  With the current model (with a green inner flush "cable") it is possible to change from one type to the other. Ours (with a blue "cable") can not have the handles switched.  We use less water since installing them. We've had them since June 2012 and they continue to function with no attention needed.
Just because something has been done and has not failed, doesn't mean it is good design.

Redoverfarm

Don both of the toilets are dual flush low consumption.  Now whether the guest know to use them accordingly I am not sure.  Just one of those things I will have to live with until later. ;D

Dave Sparks

Quote from: Redoverfarm on December 10, 2015, 01:02:19 PM
Water Well pump?   

I thought I was ahead of the consumption when I installed a Grundfos 240v pump which is a slow start using 9.8 amps.  No one ever mentioned that to attain that 9.8 amps of AC it would take 31 amps of DC.  Biggest consumption is the flush toilet.  If I could just convince the ladies to hit the woods.  Nope not going to happen.   ;)

Use a 25+ gallon pressure tank, a pressure switch and you can flush most of the night without cycling the grundfos.
"we go where the power lines don't"

Redoverfarm

Yep got that and it works fine for the family.  But there is several occasions when there is 20-25 people there and the tank doesn't have enough capacity to keep up.  But w/o an extremely large storage capacity it can not be helped.



Dave Sparks

A couples sizes up on the pressure tank in my opinion,   but with that many people....
"we go where the power lines don't"


OlJarhead

Low flush composter works for me but I never have more than 8 or 10 people and that's rare.  Then an outhouse will do the trick which we also have ;)

old_guy

Our property is essentially one big hill, which drops 500' from the top down to the water.  We have cleared several acres at the top, and will have a barn there, but do not want our house up there.  The house will be part way down the hill (200'?), on a relatively flat area closer to the water.  The kids want cabins right down by the water.

Since the hill slopes down to the north and east, the top is really the only area where we can get direct sunshine for most of the day.  That means that the solar panels will be at the top of the hill.  How should we deal with having the majority of our consumption (the house) being a couple hundred feet from the panels?  Higher voltage means smaller wires, so I expect that we will run as high a voltage as reasonable to be able reduce wire costs.  This will probably be standard 120/240 AC, but I welcome any feedback to suggest other options.

Worse yet, the cabins will be several hundred feet farther from the panels.  I expect that I could have an additional battery bank near the cabins and charge them via AC at relatively low current, so that their local batteries can provide or augment their needs, and so reduce the wire size for that long distance.  Is this feasible?  Are there reasonable options?

MountainDon

1.  House a couple hundred feet from the PV array....  It makes sense to me to series connect PV panels and run higher voltage DC to the cabin where the charge controller and batteries are located.  That is what we did, for a 325 foot distance.  In general select a solar charge controller that can handle at least 150 volts DC input like the Outback FM.  Midnight has some that handle 200 and 250 volts, Morningstar has one that does 600 volts as does Schneider in the Conext SW series. Magnum offers one that is rated for 200 volts. Some of those are quite expensive.   

Keep in mind that when you series connect PV panels to raise the voltage, the charge controller loses some efficiency in dropping the high output to 24 or 48 volts for the battery. However, with a wire run of a couple hundred feet that is probably a good trade off, IMO.

Also keep in mind you are building a system; PV panels, charge controller, batteries, inverter.  When the equipment is all from the same family they can communicate with each other. One remote can function with the CC and the inverter.

Have you determined the probable daily consumption? That determines battery bank capacity which then allows calculation for PV capacity, charge controller. Consumption also determines inverter size of course.

2.  A further 200 to 300 feet from house to a cabin or two.... How much power capacity will be needed for a cabin or two?  Need a good estimate on that too.   On first thought it would seem that running 240 VAC from house to cabin might be the best.  ???  Then split that 240 AC in a service panel to have the usual twin 120 VAC setup.  But I am out of my comfort zone on what is best for that.


Will you require 240 AC for the house?  Like for a well pump or whatever?   

As for having a second "cabin" battery bank and charging that with an AC supply, seems like there would be a lot of total loses with all the DC to AC, and AC to DC and back again if the cabin is to use AC power for lights, etc. 

No power grid available?

Anyhow that's thoughts off the top of my head... need more capacity required numbers to get more helpful.


2 final notes:  1.... regarding series connecting panels for a high voltage DC run...  The coldest possible temperatures need to be factored in as cold raises the voltage output of a PV panel. Just thought I'd mention as I have no idea of your knowledge level. All the major charge controller players have online string size and charge controller calculators.    2....  lightning is very destructive if it strikes an array.  I'd recommend giving protection a lot of thought,   especially with a hill top array.  Been there, had that done to us.....



Just because something has been done and has not failed, doesn't mean it is good design.

OlJarhead

Why not put everything in the barn up on the hill and run AC own to the houses?  You can run AC a lot further without much loss.

MountainDon

For the distances being discussed, say a maximum of 500 feet from top to bottom, there is very little difference between AC and DC transmission losses.   It is mainly a question of volts and amps.  AC does have the advantage of lower cost disconnects and fusing compared to DC.   It could be worth a look at it. 

A detailed look at what the actual AC and DC loads in the house and the cabins needs to be done before any real planning on one system vs another, IMO.

Just because something has been done and has not failed, doesn't mean it is good design.