# Solar Power Off Grid - Help w/ excess power



## turbodog (Jun 30, 2013)

I'm the stateside point of contact for some friends in Haiti. They are off-grid. (waaaaaay off!) We have intermittent contact as they are able.

They've got a pretty nice solar setup, but are 'panel heavy'. Ideas from people w/ experience on what to do with the excess power? They are hitting 100% charge by noon each day. And that's having gone through bulk, absorb, and float to get there.

Adding batteries is not an option. They would cost too much, and they have no need for extra loads at sundown/evening/night.

Electrical water heating is not a big concern, because they have no running water. Most useful thing they need water-wise is more of it, and CLEAN water.

Panel output is around 4kw. Battery bank is around 900AH @ 48v (single string). Inverter is a magnum4448. Midnight solar charge controller. Other assorted stuff... temp monitors, bmk SOC meter, etc.


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## MikeAusC (Jun 30, 2013)

How about donating the excess panels to a community that that doesn't have basics like lighting ?


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## CMAG (Jun 30, 2013)

You mentioned the need for clean water, Send the extra power to a UV light water purifier or rig a UV light in water storage tank


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## turbodog (Jun 30, 2013)

MikeAusC said:


> How about donating the excess panels to a community that that doesn't have basics like lighting ?



Panels are only usable during the day. We are dealing with people (community) that don't have shoes. They would not know what to do with panels (and related) materials if you gave them a tractor-trailer load.


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## turbodog (Jun 30, 2013)

CMAG said:


> You mentioned the need for clean water, Send the extra power to a UV light water purifier or rig a UV light in water storage tank



First, they need water (in any form) for this to work. Only water source I know of is a local river. Too far to pump it though. Besides, people would steal the pipe/wire/etc.


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## turbodog (Jun 30, 2013)

Only answer may be to do nothing.


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## bfayer (Jun 30, 2013)

Just a thought, but could they run a dehumidifier on the excess power?

I have to empty mine everyday, and Haiti is a lot more humid than my house. I pull a couple gallons out every day.

I am just talking about an experiment here, but find a small efficient dehumidifier and send it to them. See how much water they can pull out of it.

If it works then you can start looking into a more sophisticated set up that will run more efficiently.

I would think rain water collection would serve their water needs, but I guess it doesn't.


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## CMAG (Jun 30, 2013)

turbodog said:


> First, they need water (in any form) for this to work. Only water source I know of is a local river. Too far to pump it though. Besides, people would steal the pipe/wire/etc.


No need for plumbing if they carry buckets of water back to camp a UV light will kill any parasites and other nasty things google steripen a pocket version of what i am saying you put the tip with a UV light in a glass of water turn on and wait 90 seconds. a larger solar powered UV bulb could be simple as mounted to the inside cover of 5 gall pail or whatever they use ( burning there excess power) would save them from boiling water to kill germs 
Just a thought that is why I said "or rig a UV light in storage tank"


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## turbodog (Jun 30, 2013)

bfayer said:


> Just a thought, but could they run a dehumidifier on the excess power?
> 
> I have to empty mine everyday, and Haiti is a lot more humid than my house. I pull a couple gallons out every day.
> 
> ...



If you are talking about using it to generate drinking water, that's a new idea we had not though of.

If it's to dry out the house... sorry. The house is open air. The sun they get makes it waaaay to hot to close up. Even if you had grid power, I don't think you could cool that house.


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## turbodog (Jun 30, 2013)

CMAG said:


> No need for plumbing if they carry buckets of water back to camp a UV light will kill any parasites and other nasty things google steripen a pocket version of what i am saying you put the tip with a UV light in a glass of water turn on and wait 90 seconds. a larger solar powered UV bulb could be simple as mounted to the inside cover of 5 gall pail or whatever they use ( burning there excess power) would save them from boiling water to kill germs
> Just a thought that is why I said "or rig a UV light in storage tank"



Missed that, but the UV killers I have don't work well in nasty (brown/dark/etc) water. And that's what they have there...


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## CMAG (Jun 30, 2013)

bfayer :thumbsup: good thinking drink the humidity hit it w/uv light to be safe


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## CMAG (Jun 30, 2013)

turbodog said:


> Missed that, but the UV killers I have don't work well in nasty (brown/dark/etc) water. And that's what they have there...


water just has to be strained thru a old T shirt or sock first


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## CMAG (Jun 30, 2013)

worst case if they still have power to burn run a bug zapper


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## turbodog (Jun 30, 2013)

CMAG said:


> worst case if they still have power to burn run a bug zapper



Spare power disappears @ dark. After batteries are charged, any power not used is lost. So from noon till dark... there's a very significant amount of power available, but no good thing to use it on.


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## SemiMan (Jun 30, 2013)

The thing with solar is you think you have too much till you don't, and when you don't is when you really need it. They have a 40KW battery bank and a 4KW panel bank. It really comes down to what their drawn down is per day. In some ways they may have both too much panel and battery. There are certainly advantages of having lots of battery and little daily draw down ... unless the batteries are hot in which case they are going to die quick anyway.


If you have excess power you can:

- Move something
- Pump something
- Electrify something


1) Pumping for a community available well
2) Running a community water purifying system
3) Providing charging capacity for their neighbors (phones, small batteries, etc.)
4) If you have a pump, the you can consider swamp coolers.

Where in Haiti are they? I have friends doing medical work down there.

Semiman


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## HarryN (Jul 1, 2013)

There is a useful short article on wikipedia under the search title "atmospheric water generator" and some links at the bottom of the page. Some versions are based on cooling condensation (like a dehumidifyer) and some on compression.

If they really have that much excess power, perhaps they can conider to start a light manufacturing process of some kind, such as a small cnc machine shop or wood working operation.

It might be possible for them to drill a fresh water well and pump water for farm animal use into a small pond ?

If I remember correctly, Haiti is one of the original locations where mosquitos were native. If excess electricity is available, perhaps setup some kind of electrified wire grid to keep out insect pests, both for the garden and for lowering the rate of infection.


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## turbodog (Jul 1, 2013)

SemiMan said:


> The thing with solar is you think you have too much till you don't, and when you don't is when you really need it. They have a 40KW battery bank and a 4KW panel bank. It really comes down to what their drawn down is per day. In some ways they may have both too much panel and battery. There are certainly advantages of having lots of battery and little daily draw down ... unless the batteries are hot in which case they are going to die quick anyway.
> 
> 
> If you have excess power you can:
> ...



Camp Coq

No community wells. They already charge many many cell phones.

Their draw down is ~15% a day.

They have 3 honda inverter generators as backup and for portable power for construction projects.

Batteries are in a purpose-built outbuilding and are around 80-82F or so.


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## SemiMan (Jul 3, 2013)

Do they have a well? Any idea what the water temperature is?

If they could cool the batteries, they will last a lot longer. That is warm enough, especially with charging heat, to shorten the life. I am not aware of any small variable speed air conditioners, but if there was one, cooling the battery room would be a good use of excess power.

Charging battery powered lanterns (In addition to the cell phones). 

Another cool idea, budget dependent, would be a hydrogen generation system to be used for cooking gas, etc.

Camp Coq is near a river so charging a very low cost electric vehicle for daily water runs if there is no well could be a priority in conjunction with the ideas above for purification.

Semiman


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## jtr1962 (Jul 3, 2013)

Do they have some form of reliable transportation? If not, here's an idea. Buy a few electric bicycles, and use the excess solar power to charge them during the day. You could use the bikes to bring water back from the river, bring in supplies, whatever. E-bikes aren't all that expensive. And if you buy a decent one, they're pretty reliable.


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## bfayer (Jul 3, 2013)

turbodog said:


> If you are talking about using it to generate drinking water, that's a new idea we had not though of.
> 
> If it's to dry out the house... sorry. The house is open air. The sun they get makes it waaaay to hot to close up. Even if you had grid power, I don't think you could cool that house.



No not drying out the house 

Pulling water out of a continuous supply of humid air. The warmer and the more humid air the better.

A dehumidifier is just a small portable air conditioner. The refrigerant cools a coil, and the fan blows the hot humid air over the cold coil. A bucket catches the condensate (fresh water).

Not the most efficient, but if there is excess power, why not?


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## ganymede (Jul 4, 2013)

The service organization that I am with has completed many simple water supply systems for rural areas around the world. Water and sanitary are probably the main priorities there in Haiti. I am not too sure what kind of water source they have there, if they have a spring water source, they could dam it up and water could be piped (using gravity or pumps powered by PV) to elevated storage tanks closer to the village. If elevated storage tank is not an option, you could install pumps to deliver the water either to individual houses or to a central location. The model is more or less the same if the village is close to a river or a lake. If the water is deep under ground, then you would need to drill a well and install pumps to draw out the water.

Adding a simple water filtration/purification system is a great idea as well, as access to clean water can be a major issue in rural areas.

Good luck!


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## Illum (Jul 4, 2013)

turbodog said:


> Panel output is around 4kw. Battery bank is around 900AH @ 48v (single string).



Did they not size the domestic load before investing or did someone give them a good deal on the PV?

My guess is to throw a bigger inverter on there and put up a community hall that's air conditioned only during the day. An air conditioned room could be used for anything from weddings to schools to prayer halls to morgues.


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## turbodog (Jul 5, 2013)

SemiMan said:


> Do they have a well? Any idea what the water temperature is?
> 
> If they could cool the batteries, they will last a lot longer. That is warm enough, especially with charging heat, to shorten the life. I am not aware of any small variable speed air conditioners, but if there was one, cooling the battery room would be a good use of excess power.
> 
> ...




No well.

Cooking is propane, which is reasonably easy to get if you will make the multi-hour trip to town.

Haiti stuff must be servicable in-country.


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## turbodog (Jul 5, 2013)

Illum said:


> Seem okay, the battery bank is a little small. Did they not size the domestic load before investing or did someone give them a good deal on the PV?
> 
> My guess is to throw a bigger inverter on there and put up a community hall that's air conditioned only during the day. An air conditioned room could be used for anything from weddings to schools to prayer halls to morgues.



Are you kidding? That's one HUGE bank. It's close to the largest PV battery bank I have ever seen. Shipping weight for batteries alone was over 4000 lb.

The locals don't care about a/c. They want clean water, septic facilities, medical care, and enough food to eat. We would like to be able to turn the excess solar capacity into some of these.


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## inetdog (Jul 5, 2013)

turbodog said:


> Are you kidding? That's one HUGE bank. It's close to the largest PV battery bank I have ever seen. Shipping weight for batteries alone was over 4000 lb.
> 
> The locals don't care about a/c. They want clean water, septic facilities, medical care, and enough food to eat. We would like to be able to turn the excess solar capacity into some of these.



If they use kerosene or other fuel for light in their homes at night, the excess PV energy during the day could charge a lot of small battery powered lamps. Lithium battery technology is too dangerous and expensive, but NiCad or NiMH batteries can be pretty rugged and inexpensive. Don't go for the super cheap cells used in solar landscape lights. 

If nothing else, the energy would give good light for kids doing school work.


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## Illum (Jul 6, 2013)

turbodog said:


> Are you kidding? That's one HUGE bank. It's close to the largest PV battery bank I have ever seen. Shipping weight for batteries alone was over 4000 lb.
> 
> The locals don't care about a/c. They want clean water, septic facilities, medical care, and enough food to eat. We would like to be able to turn the excess solar capacity into some of these.



Yeah, that is quite big, and I didn't retain where it says 48VDC. 

I'm not sure how to clean water using surplus electricity beyond using it to boil water and collecting the condensate by circulating cold sea water in a chill loop. All in all very expensive and likely impossible to build on site


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## mesa232323 (Jul 7, 2013)

How about some incandescent Christmas lights in the shape of a dollar sign?


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## SemiMan (Jul 7, 2013)

It sounds like a big battery bank but to those who do off-grid its not so big and not nearly big enough for air conditioning.

Lithium lifep04 is more than safe enough FYI and best for hot climates. 

Heating water using PV is a waste. Solar thermal is far more efficient and with evacuated tube collectors easy to get high temps for boiling. 

Unless you solve the water supply issue not much to be done besides charge things and maybe set up a small classroom.


Sent from my Nexus 4 using Tapatalk 4 Beta


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## turbodog (Jul 7, 2013)

SemiMan said:


> It sounds like a big battery bank but to those who do off-grid its not so big and not nearly big enough for air conditioning.
> 
> Lithium lifep04 is more than safe enough FYI and best for hot climates.
> 
> ...



Yeah. If there was a well, the excess power could go to running the well pump. As it is, you can't do much useful.

Then there's the whole theft problem. They are close enough to the river that it's possible to run wiring and pipe and pump from the river. The water is not clean, but at least everyone would not have to go get it in buckets. The darn locals (that these people are helping) would steal every bit of it the second your back is turned.

Perhaps a well will be drilled in the future.


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## Lynx_Arc (Jul 7, 2013)

Too bad you can't use an refrigerator to pull moisture out of the air and make water with the extra power.


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## Ken_McE (Jul 7, 2013)

Lynx_Arc said:


> Too bad you can't use an refrigerator to pull moisture out of the air and make water with the extra power.



You can, it's just that when it's set up that way they call it a dehumidifier. Not sure how it tastes.


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## Lynx_Arc (Jul 7, 2013)

Ken_McE said:


> You can, it's just that when it's set up that way they call it a dehumidifier. Not sure how it tastes.



they could always run the water through a filter afterwards


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## Ken_McE (Jul 7, 2013)

turbodog said:


> Ideas from people... on what to do with the excess power?



You need something the locals can turn into cash.

If you can't store it then you need some kind of work that can be done during the day. The basics are either turning a wheel or running a pump. You could electrolize water to make cleaning fluid, or use electrolysis to make Hydrogen and Oxygen, or electroplate metals, but those are probably too complicated to do out in the back country.


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## Ken_McE (Jul 7, 2013)

Lynx_Arc said:


> they could always run the water through a filter afterwards



You have to remember that Haiti is staggeringly poor. They are rapidly working their way towards having an entire island of nothing but mud. They can barely afford rice and beans, never mind filters. Dehumidifier water should have an unpleasant metallic taste from the aluminum condenser. It would also be low in minerals (people need minerals), and you would have to watch for mold and mildew growing in the machine and contaminating the water.


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## turbodog (Jul 7, 2013)

Ken_McE said:


> You have to remember that Haiti is staggeringly poor. They are rapidly working their way towards having an entire island of nothing but mud. They can barely afford rice and beans, never mind filters. Dehumidifier water should have an unpleasant metallic taste from the aluminum condenser. It would also be low in minerals (people need minerals), and you would have to watch for mold and mildew growing in the machine and contaminating the water.



Exactly. The CIA considers Haiti a failed country.

https://www.cia.gov/library/publications/the-world-factbook/geos/ha.html

https://www.cia.gov/library/publications/the-world-factbook/geos/ha.html


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## Ken_McE (Jul 8, 2013)

turbodog said:


> Exactly. The CIA considers Haiti a failed country.



I agree with them, but did not want to insult you or your friends. If they can turn that excess power into some useful enterprise, then more power to them. To you or me a few hundred watts is too small to notice, but if some local can use it to cut or grind, plate or polish, water a garden, come up with something salable, then to them it's (potentially) a big deal.

The nice thing about electroplating would be that you could toss in a June Bug, or a starfish or coral or anything, copper plate it, glue a pin on the back and sell it for jewelry.

The bad thing about it is that you are working with strong acids, and I seem to recall that you have to keep the solution inside a certain chemical range for it to work.


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## Badbeams3 (Jul 8, 2013)

Great ideas here. Way better than the 3D home theater set up I was going to suggest for the community to gather round in the evenings.


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## turbodog (Jul 16, 2013)

For now, they will hang tight with what they are doing.

Single biggest thing that would benefit them and the community would be to find someone that w/ drill a well. We've had someone searching for over a year with no luck. Drillers (in country) simply don't want to drill a well for them, and no amount of money seems to change that. Guess *some* in Haiti are not that poor.


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## Ken_McE (Jul 19, 2013)

turbodog said:


> Single biggest thing that would benefit them and the community would be to find someone that w/ drill a well.



A lot of Haiti is just limestone. How about men working in shifts with pick and shovels, dynamite if it's available? My ancestors dug wells by hand. Maybe they can too. They can even use that surplus power to send light and air down the shaft.


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## turbodog (Jul 24, 2013)

Ken_McE said:


> A lot of Haiti is just limestone. How about men working in shifts with pick and shovels, dynamite if it's available? My ancestors dug wells by hand. Maybe they can too. They can even use that surplus power to send light and air down the shaft.



I don't want to be too negative, but the haitians have no clue about sanitation. I would take about 1 day for someone to send a bucket down the well for water, a bucket that was just used for a toilet.

Would have to be a well with a sealed top to prevent aquifer contamination.


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## Ken_McE (Jul 28, 2013)

_
Would have to be a well with a sealed top to prevent aquifer contamination.
_
Is hand digging at all possible? If so you could dig by hand, run a pipe, mount a hand pump on it, and brick the opening closed.


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## turbodog (Aug 2, 2013)

Ken_McE said:


> _
> Would have to be a well with a sealed top to prevent aquifer contamination.
> _
> Is hand digging at all possible? If so you could dig by hand, run a pipe, mount a hand pump on it, and brick the opening closed.



The current intel we have is that the wells in the area (if any) must be drilled quite deep to overcome the mountains. And that nrings in the need to drill through rock, real rock.


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## turbodog (Aug 28, 2013)

Drilling company has been found that w/ drill a well there. They are conducting a geological survey currently.

Now if we can just get the battery problems resolved. Apparently, the solar company didn't do all they should have on pre-programming the charge controller. Batteries are under charged, and a cell has died.

On the good news of that, we find that rolls/surrette batteries come apart and it's possible to replace a single cell. Right now, the bad cell is out, and it's been jumpered. This is very good news. A whole battery is >350lbs, whereas a cell is only ~95. Shipping costs, customs, and strained backs...


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## Hooked on Fenix (Sep 1, 2013)

Seems like your best bet might be using the excess power for transportation. If you use the power to charge up some electric bikes, scooters, or maybe a small plug in hybrid car, you can transport water and food to the property without having to worry about guarding a system to pump water against theft. Transportation to and from work for any locals you can trust will help the local economy as well. I think some sort of electric or hybrid car might be best overall as you can transport more water and food and drive people around without having to loan out single person bikes and scooters that might not come back. The drawback to this idea is that most likely, gasoline powered vehicles are probably already in use and the fuel may be cheaper in the long run than buying electric powered vehicles. Also, servicing or purchasing these vehicles might be difficult in Haiti. If you can use the electricity to produce hydrogen through electrolosis, you might be able to have fuel for cooking, transportation, and have distilled water as a byproduct, but you still have the problem of transporting the water to the property. If you can do this cheaply, this might get you the most bang for your buck.


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## broadgage (Sep 1, 2013)

I would consider some small scale electric cooking during the day, thereby reducing propane consumption.
A microwave oven, electric boiling ring, or table top sized conventional oven should be withing the system capacity.
It would seem that several KWH a day is spare, that could run a kettle, a microwave oven, and a boiling ring for several hours a day in total, though probably only one appliance at a time.
As the propane has to be fetched from a considerable distance, there would be a saving in time and trouble and road vehicle fuel, as well as money.


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## turbodog (Sep 2, 2013)

Hooked on Fenix said:


> Seems like your best bet might be using the excess power for transportation. If you use the power to charge up some electric bikes, scooters, or maybe a small plug in hybrid car, you can transport water and food to the property without having to worry about guarding a system to pump water against theft. Transportation to and from work for any locals you can trust will help the local economy as well. I think some sort of electric or hybrid car might be best overall as you can transport more water and food and drive people around without having to loan out single person bikes and scooters that might not come back. The drawback to this idea is that most likely, gasoline powered vehicles are probably already in use and the fuel may be cheaper in the long run than buying electric powered vehicles. Also, servicing or purchasing these vehicles might be difficult in Haiti. If you can use the electricity to produce hydrogen through electrolosis, you might be able to have fuel for cooking, transportation, and have distilled water as a byproduct, but you still have the problem of transporting the water to the property. If you can do this cheaply, this might get you the most bang for your buck.



Haiti has NO infrastructure to support or sell these vehicles. It's a 5 HOUR drive by 4x4 to get to town.

All of you guys, please go read the CIA factbook on Haiti.

There known kidnappers that live in the local community that just walk around like anybody...


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## turbodog (Sep 2, 2013)

broadgage said:


> I would consider some small scale electric cooking during the day, thereby reducing propane consumption.
> A microwave oven, electric boiling ring, or table top sized conventional oven should be withing the system capacity.
> It would seem that several KWH a day is spare, that could run a kettle, a microwave oven, and a boiling ring for several hours a day in total, though probably only one appliance at a time.
> As the propane has to be fetched from a considerable distance, there would be a saving in time and trouble and road vehicle fuel, as well as money.



I'll mention these to them. Currently, cooking is done in a cook house out back over fire. I think the source is propane, in about a 100 gallon tank. The cook house is doubling as a shared cooking place for several families.


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