# Off Grid Power, Batteries, PV Panels, Generators...



## JeepHammer

Battery Basics,
Things you MUST know if you are going to use Batteries!

BATTERY MYTHS,
1. Batteries Discharge Faster When Sitting On Concrete.
*FALSE!*

This was true when Thomas Edison was making 'Radio' batteries, but they are no longer made in metal cases.
Modern batteries will actually benefit by being in contact with a concrete floor, helping to stabilize the temprature better.

Batteries WILL discharge if you let the tops collect dust and moisture! Dust and moisture will actually 'Short' the terminals out and discharge the battery!
..................

2. Batteries Work Better When They Are Hot.
*FALSE!*

Batteries will give optimum output around 62°F to 68°F.
Warmer will shorten the life of the batteries, 
Colder will reduce effective output of the batteries.
...................

3. Any Water Will Do.
*FALSE!*

EVERYTHING in that water will adversly effect your battery!
Chlorine will neutralize the acid, 
Fluoride will build up on plates,
Calcium will cause scale on the plates,
Metals will cause corrosion and shorting between plates,
The list goes on!

*USE DISTILLED WATER ONLY!*
Distilled water will NOT adversely effect your battery and will readily mix with the acid in the cell.

DO NOT USE 'DRINKING' WATER that might have salts or other things added for 'Taste', just plain old Distilled water!
.................

4. You should add 'Acid' to the cells.
*FALSE!*

Your battery comes with all the acid it should ever need!
As the water evaporates away, the acid simply concentrates in the cell.
You should add DISTILLED WATER to the cell to dilute the acid/water electrolyte mixture back to a proper concentration.

*IF YOU OVER FILL A CELL...
Don't panic!
And DO NOT suck the water out because you will be taking acid out with it!
Simply skip over that cell until the excess water evaporates naturally, then maintain the proper electrolyte level from that point on.*
.................

5. You can check a batteries' health by testing for voltage.
*FALSE!*

You can check a batteries' health by one of two methods,

A. With a hydrometer. 
Check the specific gravity of the individual cells to see if they are 'Fully Charged' or not.
This is easily accomplished with the battery/cells still hooked up in the battery set or bank.
You simply sample the liquid from each cell with a 'Hydrometer'.
Hydrometer - Wikipedia, the free encyclopedia

B. By doing a 'Load Test'.
Take the battery out of it's battery 'set' and check it's state of charge,
Then load that battery over a period of time to see if it will carry the specific load for a designated period of time.
..................










REMEMBER!
The larger the amperage, the larger the cables have to be to carry that amperage,
The farther apart the terminals have to be to keep arcing from happening, and generally the more expensive everything will be to install Parallel battery systems.


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## JeepHammer

.
*Basic PV array & connections.*

There are a lot of things you should consider when installing PV arrays.
Again, The golden rule is,
*'APPLICATION, APPLICATION, APPLICATION!'*

If you intend to charge batteries directly from a PV array, then you will only need enough batteries to reach the charging voltage limit... Or use a 'Charge Controller'.

Small PV panels have been used for years to directly 'Trickle Charge' batteries in seldom used vehicles or for seldom used appliances.
For us country folk, we use PV panels to charge batteries for electric fence 'Chargers'.
I use one to keep the two deep cycle batteries on my car trailer winch charged for the weeks/months I might not use the car trailer for anything...
Many people use small PV panels to keep boats, RV's, or what ever charged up when not in use...

The next step in direct PV solar battery charging is larger scale...
I use two large (but wrong voltage for my home system) to charge batteries in an electric vehicle.
Lots of batteries make up a 'Battery Bank', and since there are plenty of batteries, I need a larger solar panels to charge them up.
In my case, the two panels make up 24 volts, and I use a small charge controller to keep them from Over Charging the vehicle's battery bank.

*PV BATTERY CHARGING,*









The next step would be batteries for an 'INVERTER'.
http://en.wikipedia.org/wiki/Inverter_(electrical)
Emergency batteries, like an emergency battery backup for computers, or for your refrigerator, freezer, maybe a low current consumption light or two, would be handled in this same way.
An inverter would convert the battery power from DC (Direct Current) to AC (Alternating Current) so your household appliances will function from battery power.

Now, we are up to having several *Solar Panels, Charge Controller, Batteries & Inverter.*
I will cover 'Inverters' in a later post...
This is a basic, Modern, Solar PV system!

Your PV array should be as many panels as you can afford!
You can mix and match panels if you have the correct inverter (Multiple Inputs for DC).
There is no such thing as 'Too Much' production capacity, since larger panels are $500 to $1,500 each, it's a self limiting proposition!

You CAN start with just two or three, and buy & add on as you go!
I suggest you do this!
This allows you to size your system to your needs as you go, so you aren't 'Too Big' and waste money.

In my particular case, we have 'Net Metering', which means when I'm not using the current I produce, I send it back to the electrical 'Grid', and turn my meter backwards...
Building credits for when it's dark, or an appliance too big for my panels kicks on and I have to buy electricity...
My bill usually reads "Amount due $0.00" and I REALLY like that part!

I DO NOT get money for overproduction! 
Any extra production I made at the end of the year is NOT paid to me,
SO,
That means I'm right about where I need to be, with a 'NET' of $0.00 cost to me.

Some states require the electric utility PAY YOU for the extra production,
And some states even require they pay you EXTRA, above the 'Consumer' rate, for the 'Carbon Free' production! A GREAT IDEA!

In my case, When the air conditioner runs long and hard, I have to pay a little in, and I can live with that...
If I had electric stove, electric heat, or electric hot water heater, I'm sure that bill would be MUCH more, and I'd add extra panels to recover some of that money!
But, as it stands, I come out about even if the summers aren't too hot for too long, and that is about all a guy can ask for!
---------------------------------------------------------------------

*PV ARRAY WIRING FOR HOUSEHOLD CURRENT PRODUCTION.*

FIRST AND FOREMOST!
*CHECK THE DC INPUT VOLTAGE OF YOUR INVERTER! *
Doesn't matter if you have Grid Intertie Synchronous Inverter, or just a stand alone DC to AC Inverter!
You DO NOT want to overpower your inverter and burn it up!

Inverters _USUALLY_ have a WIDE RANGE of input voltages, and you need to know the limits before you start sizing the PV arrays for them!

SERIES, one wired into the next one, will raise voltage.

Series Strings wired in PARALLEL will raise the AMPERAGE while keeping voltage constant.

*PV HOME PRODUCTION ARRAY BASICS,*


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## JeepHammer

*PV Panels, Grid Intertie and Non Grid Wiring*

.
Grid Intertie Systems.
Depending on the number of PV Panels, 
(Photo-Voltaic Panels)
You can significantly reduce or eliminate your electric bills.

Small PV systems will power about everything in the house as long as you keep a eye towards energy efficiency.
Compact Florescent light bulbs,
Energy efficient refrigerators, freezers, ect.
Turning of the power to parasitic loads like 'Stand-by' on TV's, VCR's, DVD's, Stereo Equipment, Computers, ect.

You will need a MASSIVE PV array to power things like,
Electric Hot Water Heaters,
Electric Cloths Dryers,
Electric Furnaces,
Electric Stoves,
Air Conditioning Units,

That is were a grid 'Intertie' system comes in,
With small panels, you power the 'Normal' running loads of the house in the day time.
If nothing is on, then you turn the meter backwards and gain credits.
If a heavy load comes on, like the Air Conditioner or Furnace, then the grid takes over and runs the appliances until that large drain device kicks off.

You can easily accumulate enough credit through the day to run the heavy drain devices and still maintain a credit.

In my state, you don't get paid back the 'Excess' current you return to the grid, but you CAN cancel your bill out by turning the meter backwards.
It's called 'NET METERING'.

In some, more 'Enlightened' states, the Electric company not only has to pay you for your extra production, but they have to buy the 'Carbon Free' current at a premium price!

Anyway, this shows a typical Grid Intertie system,
With, and Without Batteries.










REMEMBER!
Batteries WASTE about 70% of the electricity you throw at them!
They waste it as resistance in the terminals,
They waste it as heat both charging & discharging,
They waste it in the electrical to chemical storage process,
They waste it in the chemical to electrical discharge process...

Batteries just aren't very efficient, but if you intend to live 'Off Grid' they ARE a 'Necessary Evil'.
You simply can't afford to run a generator every time you want to use the microwave or watch TV!...

SO, With that said,










I DID NOT include the battery charger you will need to recharge the batteries from the generator when there has been clouds for several days, or if you don't have very many batteries or very many PV Panels...

With a generator supplied Battery Charger (Consider A Generator With Starter/Alternator the same voltage as your battery banks... In this case, 24 Volts.


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## JeepHammer

Just saving space for next variation.


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## Erika123

*About off grid energy*

If you would like to make good use of the sun, it is very doable without costing a lots amount of money. See this Solar Panels and System. Hardy Solar Home Stezader 4 kW off grid energy generator system.1,500 Watt off grid Solar Panel System.
_______________________
 off grid


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## Iron_Bran

*This is impressive*

I really like this forum - y'all clearly know what you are talking about. I appreciate your conclusions that batteries are really inefficient - people get so hung up on one little spec, and decide one size battery will work perfectly and another is total garbage.

In reality, batteries need to be sized to the system, but there are more inefficiencies throughout the system that you could ever imagine accounting for.


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## MrSfstk8d

This is a really great primer on PV and intertie Jeep Hammer. Great set of posts, and good visuals, especially for those who may not be at all familiar.


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## ZoomZoom

Great series of posts.

I will toss something out though. When connecting DC batteries, particularly in parallel, it's best to match their size, age, output. If you connect 2 mismatched batteries, the weak battery will draw from the strong and generally make a mess of things. Think of when you connect jumper cables from a good to a dead battery. The bad battery will draw from the good until they're equal. Basically, you end up with 2 half-dead batteries when now renders both of them inadequate.


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## AzDesertRatMarine

*Great job!*

This is a GREAT post! Well Done!


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## rhrobert

*Build your own battery*

Don't know if any of you will find this useful, however it might make for some good experiments:


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## UncleJoe

Very cool. Well worth saving. :thankyou:


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## YouNeedBatteries

You can also buy a sealed, maintenance free, factory activated battery. It has less of a shelf life, but you won't have to deal with constantly refilling the acid.


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## Davarm

Some more affordable Solar Pannels and Wind Charger

Solar Panels, PV Systems and Inverters Distributor
products_id_760 | 500W Max/12V Hybrid Wind Turbine 5-Blade 400W Rated - 1000W Inverter Included - Applied Magnets & WindMax Wind Turbines


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## GaryS

Just want to share a thought about being independent of the power grid.

Last spring I installed a 20kw whole house generator that automatically starts and takes over supplying power if commercial power is out for a couple of minutes.

We recently had a power failure when a car hit a transformer. My generator did exactly what it was supposed to, and within minutes my house was the only one in our development that was brightly lit. That's the rub. I stood out like a sore thumb, and even though I went to the neighbors and told them they could run an extention cord if power was off for long, I sensed some resentment that I had something they didn't.

I turned all the lights off and sat in the dark while the generator was burning propane at the rate of two gallons an hour. If power had been off for days, as it sometimes is, I would have been the most hated person in the development.

I guess what I'm saying is that if you prepare, you might not be very popular when your preparations become the center attraction.


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## LincTex

GaryS said:


> I guess what I'm saying is that if you prepare, you might not be very popular when your preparations become the center attraction.


There have already in this country cases of people getting killed over a generator dispute. In that one case it was the noise, but others will very easily want your power as well.


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## Nadja

I live so remote, that running a gennie doesn't count. But 99% of my off grid house power comes from my solar system. But, living in the city, if you flaunt it, you may just lose it. Like driving a rolls royce to the really bad part of town. Not good


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## GaryS

Nadja said:


> I live so remote, that running a gennie doesn't count. But 99% of my off grid house power comes from my solar system. But, living in the city, if you flaunt it, you may just lose it. Like driving a rolls royce to the really bad part of town. Not good


That's what is really bothersome. I live in a small, rural development four miles from a very small town and a hundred miles from a city. Even rural folks don't have the same mindset that prevailed when I was young. Sad to think that being prepared puts a target on your back no matter where you live. Apparently the only difference between living in a city or in the boonies is the number of people drawing a bead.


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## oldvet

GaryS said:


> Just want to share a thought about being independent of the power grid.
> 
> Last spring I installed a 20kw whole house generator that automatically starts and takes over supplying power if commercial power is out for a couple of minutes.
> 
> We recently had a power failure when a car hit a transformer. My generator did exactly what it was supposed to, and within minutes my house was the only one in our development that was brightly lit. That's the rub. I stood out like a sore thumb, and even though I went to the neighbors and told them they could run an extention cord if power was off for long, I sensed some resentment that I had something they didn't.
> 
> I turned all the lights off and sat in the dark while the generator was burning propane at the rate of two gallons an hour. If power had been off for days, as it sometimes is, I would have been the most hated person in the development.
> 
> I guess what I'm saying is that if you prepare, you might not be very popular when your preparations become the center attraction.


This may sound completely cold hearted but, they could have done the same as you or at least purchased a smaller gas powered gennie for emergency power. I would not loose a seconds worth of sleep worrying about them resenting or hating me just because I had some foresight and planned for the worst.

Don't get me wrong I have compassion and show it when it is needed or warrented, but the folks that get bent out of shape just because you are taking care of your own can BITE MY SHORTS!


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## Nadja

Old Vet, I am an old vet myself and agree with you. But, not everyone would be set up with the type of mindset's we have. Plus, although he says he is mostly rural, having neighbors tells me he is not as rural as I am for instance. Everyone has different circumstances in life and they all need to be delt with differently.


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## AzDesertRatMarine

*How remote is remote enough?*

Like Nadja, I live in a very remote part of Az, and all my power comes from solar and wind. I see my neighbor drive by about once-a-week (yes, just one neighbour in about a 3 mile radius, maybe 5 in 10 miles, etc). Town is about a 20 minute drive down a dirt road, with the city being about another 15 past that.

that said, if my better-looking-half has the lights on before I drive in, I can spot our ranch about 1/2 a mile away. Being the only light in a remote area can be just as bad as being the only light in the 'burbs.

Food for thought.


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## oldvet

AzDesertRatMarine said:


> Like Nadja, I live in a very remote part of Az, and all my power comes from solar and wind. I see my neighbor drive by about once-a-week (yes, just one neighbour in about a 3 mile radius, maybe 5 in 10 miles, etc). Town is about a 20 minute drive down a dirt road, with the city being about another 15 past that.
> 
> that said, if my better-looking-half has the lights on before I drive in, I can spot our ranch about 1/2 a mile away. Being the only light in a remote area can be just as bad as being the only light in the 'burbs.
> 
> Food for thought.


Not being able to see the cabin light or the cabins is exactly why my future SIL picked the place he did.

It is 33 acres set back on a secondary road several miles from a Farm to Market road. 
The Cabins or their lights cannot be seen from the road that passes by the front gate. The clearing containing the cabins is surrounded by dense woods that extend to the road. We have several Feed and garden plots located in the wooded areas that are also not visible to the public.

Getting back on subject we are planning on going totally wind and solar, as we can afford it and "IF" we have the time left us to do it. We have a shallow well that produces some fairly "nasty" iron laden water, but we are planning on having a deep well put in that will be powered by wind with solar as backup.


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## Tirediron

GaryS said:


> That's what is really bothersome. I live in a small, rural development four miles from a very small town and a hundred miles from a city. Even rural folks don't have the same mindset that prevailed when I was young. Sad to think that being prepared puts a target on your back no matter where you live. Apparently the only difference between living in a city or in the boonies is the number of people drawing a bead.


you aren't kidding we are surrounded by acreages where the whole place needs grid power to function , how many have a generator , not many. My sister drives a school buss and she hears kids talk about the things that their parents run out of, even though one or both parents just commuted home from their job in the city. We live a 4000 + ft @ 52* latitude, we can have some weather but people just don't pay attention.


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## AzDesertRatMarine

_*OldVet said = but we are planning on having a deep well put in that will be powered by wind with solar as backup. *_

If you already have your plans for this - I for one would like to hear them as I am trying to work out the same issue of how to power a DEEP WELL pump with wind and/or solar.


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## Expeditioner

AzDesertRatMarine said:


> that said, if my better-looking-half has the lights on before I drive in, I can spot our ranch about 1/2 a mile away. Being the only light in a remote area can be just as bad as being the only light in the 'burbs.
> 
> Food for thought.


Blackout the windows - shutters, shades, drapes, paint the panes black, etc.


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## Calista

Thanks to the OP for those incredible visuals and easily understandable text about off-grid power. 

Here in the Pacific NorthWET (and the forecast tonight is for 4 inches of rain, followed by 3 inches tomorrow and the next day -- followed by "areal flooding" -- gee, ya think??? -- I can only dream about solar power, as the sun in the sky for us is usually just a brighter spot against the gray clouds nine months of the year.

So DH and I, having leased a house on two acres that came with a half-filled 500-gallon propane tank, want to purchase a PORTABLE PROPANE GENERATOR for the expected power outages usually caused by all those downed tree branches when the winds get frisky. (Our landlord will not allow a transfer switch.)

It seems that all the information online concerns propane gennies for RVs, and I'm floundering here about what brand and KW rating I should purchase for reliability, quality, and usage in a HOUSE, not an RV.

I'm mostly concerned with our two packed freezers and two fridges usually full of perishable food. Any advice and tips would be gratefully accepted!


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## LincTex

Check Craigslist, I bought a 4Kw Onan from an old RV that was dual fuel (gasoline/propane) for $150. Old RV generators are the best deal, always. The older Onans ran at 1800 RPMs, which mean they last 20 years instead of the 3600 RPM generator which last 1-2 years.

4Kw is way too big for what I really need....but I plan to charge batteries with it for the 2-3 hours it would be run each day. I am going to try to convert it to Woodgas, if I can get 2Kw out of it on woodgas that will be plenty of electricity for me for 3-4 hours at a time.


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## oldvet

AzDesertRatMarine said:


> _*OldVet said = but we are planning on having a deep well put in that will be powered by wind with solar as backup. *_
> 
> If you already have your plans for this - I for one would like to hear them as I am trying to work out the same issue of how to power a DEEP WELL pump with wind and/or solar.


Not yet, it is still in the "gum bumping" stage until we can get the funds together for the well and solar/wind power, sorry I couldn't be of more help.


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## Nadja

A couple of people I know, put in deep wells operating off of a Jack Pump. Looks like an oil pump. That is powered by solar panels only. Starts pumping water when the sun comes up and shuts down when there is no more sun.


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## Tirediron

Nadja are you talking about the system that lets you run a deep well hand type pump with a motor of some kind . they are called pump jacks here
Monitor Baker ZA pump jacks and Dempster pump jacks for pumping livestock water from wells

that system, would prolly be the best idea as far as reliability goes, and could easily be returned to hand pump.


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## LincTex

We had one exactly like this on our farm:










Our well was 80 feet deep, and with a 3/4 HP motor it was working. I don't know how big of a motor you can put on one (if a very deep well) until you start stripping gears or shearing keys.


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## Nadja

Sorry, our wells start at about 300 feet and then get really deep here. Those won't work around here,.


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## oldvet

Nadja said:


> Sorry, our wells start at about 300 feet and then get really deep here. Those won't work around here,.


Is it then even possible to power a deep well (300 ft. or more) pump with wind or solar or a combination of both. Sorry but I guess my ignorance is showing.


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## LincTex

Nadja said:


> Sorry, our wells start at about 300 feet and then get really deep here. Those won't work around here.


In Polson, Montana where I lived and worked for a while, my boss's water well was 800 feet deep. They used compressed air that had a line down to the bottom and used rising air bubbles to push the water up. The flow rate was pretty low (ran 24 hrs a day), and the water was silty. It was dumped into a 2000 gallon concrete cistern that had to have all the silt cleaned out once a year. Despite all that, it was good water and had good taste.


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## Tirediron

A person would have to contact the manufacturer but here are a couple of sources Hand Well Pump Shallow Water Well Deep Wells Solar Adaptable
and deep solar Solar Powered Deep Well | Surface Mount Water Pumping Systems

the problem that I see with a deep well solar powered pump is the sheer weight of the water column, this could be off set some what by pumping into a cistern ,to avoid line pressure but it is still a head ache

air pump link (may be more for dirty water than depth) How Buffalo Pumps Work | Air Lift Pump | Air Compressor Pump


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## Meerkat

Hello to all my helpful posters on this thread.Yall have helped me so much with solar and mechanic work.
We have a well but not sure if an affordable hand pump will work on it. Tried that with well co.made an enemy fast when it did'nt work right. So gave up but always open to new suggestions.


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## LincTex

oldvet said:


> Is it then even possible to power a deep well (300 ft. or more) pump with wind or solar or a combination of both.


Yes, with the right set-up



Tirediron said:


> the problem that I see with a deep well solar powered pump is the sheer weight of the water column, this could be off set some what by pumping into a cistern


Yes, correct - - the use a normal pressure pump (or gravity if on a hill) for delivery from there.



Tirediron said:


> air pump link (may be more for dirty water than depth) How Buffalo Pumps Work | Air Lift Pump | Air Compressor Pump


That must be how the guys in Montana did it.

Meerkat, how deep is the well?

Is the casing big enough to drop a standard Shur-Flo pump from an RV/camper down inside it?


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## BlueShoe

Nice thread.
Battery cases also used to be made of glass so setting them down and scooting them on concrete often chipped/broke them, and could cause leaks/failure.


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## Nadja

oldvet said:


> Is it then even possible to power a deep well (300 ft. or more) pump with wind or solar or a combination of both. Sorry but I guess my ignorance is showing.


Yes it is. Around here they use jack pumps to work the well, powered by solar panels. When the sun comes up, the pump starts. And of course if your tank is full, then you can walk out to it and manually shut it off. Type in "solar jack pump" into google and it should bring you up some. If not , you can contact this guy, as I framed his house about 12- 13 years ago, and that is what he does. Solar , Wind, and solar jack pumps. He goes all over the world installing for the govt in really remote areas.

Solar Exchange, Matt Hamilton, 928-536-4026 or email at: [email protected]. He is Mormon so, don't expect to reach him before weekdays


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## Nadja

oldvet said:


> Is it then even possible to power a deep well (300 ft. or more) pump with wind or solar or a combination of both. Sorry but I guess my ignorance is showing.


I just answered this, so skim through the posts for the info. The answer is Yes by using a Solar powered Jack Pump. They work great.


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## Redbone15367

Very nice and simple. Thank you for putting it out here....


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## Tex

Nadja said:


> Yes it is. Around here they use jack pumps to work the well, powered by solar panels. When the sun comes up, the pump starts. And of course if your tank is full, then you can walk out to it and manually shut it off.


You can use a float switch to shut off the pump or just pipe your overfill to feed a garden or stock tank.


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## RodUSMC

Thanks for the great post!


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## PFCHAWK

This is great post I'm saving money now for a " off grid " system. How complicated is to hook up a generator to back up solar and to charge batteries????


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## MadMartiggan

Quick Question: If I already have an array setup would it be affected by an EMP? or would it be best to set it up, test it, then disconnect it and store it in a Faraday Cage till I need it as a Backup? (even if it is grounded)?


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## LincTex

MadMartiggan said:


> Quick Question: If I already have an array setup would it be affected by an EMP? or would it be best to set it up, test it, then disconnect it and store it in a Faraday Cage till I need it as a Backup? (even if it is grounded)?


I wish I really knew.

I have both - - a small set-up for experience working with it/experimenting, and to see what the system really does - - and then also stored spare components.

Not big enough to run a whole house though.... just enough for LED lights at night and a few kitchen appliances when making meals.


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## jsriley5

Hey Mad I have recently spent over a week reading everything I could find on EMP and how to protect against it. There were a couple articles that said you could set up your panes and surround them with a mesh cage to protect them but the problem I have with that is that the wiring running from it would still act as a accidental antennae to pick up the emp and take it to the panels, charge controller. Inverter ETC the only way I see it working is if all that was in the cage including the storage bateries. All I could find about sheilding the wiring made it seem like a expensive and daunting experience and likely to fail. I may try to do it with a small test set, but will keep the bulk of my stuff put in storage till after the fact. My head is still spinning from all the diferent ideas suggestions and what will and what wont work looks like the experts really aren't all that positive sure what works and what doesn't. 

OK now for what I started in the thread for. Does anyone know a good source for never filled or pre charged deep cycle batteries for storage. I thought I"d get them through my cousins shop from interstate but my cousin says the interstate man says he can't get em un filled, just the empty but pre charged. Kinda bummed me. So back to the drawing board. Also while reading this article to see if it was alrady discussed I noticed someone mention how inneficient batteries were. And that each connection was a loss. I guess I knew that but never really thought of it. So using that reasoning am I better off then getting one really large battery in 12 volt rather than say two 6volt large batteries that would supposedly equal the same ap hr. I notice most or many of the systems I see seem to run towards multiples of the 6v batteries rather than fewer of the larger batteries is there a justification for this? OK done bending your ears for now. If you have read this far thanks very much.


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## helicopter5472

AzDesertRatMarine said:


> Like Nadja, I live in a very remote part of Az, and all my power comes from solar and wind. I see my neighbor drive by about once-a-week (yes, just one neighbour in about a 3 mile radius, maybe 5 in 10 miles, etc). Town is about a 20 minute drive down a dirt road, with the city being about another 15 past that.
> 
> that said, if my better-looking-half has the lights on before I drive in, I can spot our ranch about 1/2 a mile away. Being the only light in a remote area can be just as bad as being the only light in the 'burbs.
> 
> Food for thought.


Might be a good idea to get black-out curtains for the windows/rooms that your using lights at nite for...just sayin


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## Iron_Bran

*Batteries in AZ?*

We have 2 batteries like this running systems near Snowflake, AZ... is that close to your area?


helicopter5472 said:


> Might be a good idea to get black-out curtains for the windows/rooms that your using lights at nite for...just sayin


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## talob

Whats the general rule on minimum solar panel watts to battery watts, in other words say a 100ah 12v battery= 1200w? How many panel watts?


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## cowboyhermit

100ah 12V battery=1200Wh(watt hours)
It really depends on the load and the amount of reserve capacity you want to have (length of time you can run without sunlight). In places with long nights in the winter like we have more battery bank per panel is recommended.
In a theoretical situation a 100 watt panel would take 12hr to charge that 100ah battery however charging is not 100% efficient (not even close) but that is balanced by the fact that you never want to discharge a battery far enough to get that full 100ah out.

For most cases I would say 100 watts/100ah battery but I have set up systems with 2x100ah batteries for every one 100W panel and conversely 2x100W panels for every 100ah battery depending on the circumstances. Of course most full sized panels are over 100W now, just makes for easier calculations.


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## talob

cowboyhermit said:


> 100ah 12V battery=1200Wh(watt hours)
> It really depends on the load and the amount of reserve capacity you want to have (length of time you can run without sunlight). In places with long nights in the winter like we have more battery bank per panel is recommended.
> In a theoretical situation a 100 watt panel would take 12hr to charge that 100ah battery however charging is not 100% efficient (not even close) but that is balanced by the fact that you never want to discharge a battery far enough to get that full 100ah out.
> 
> For most cases I would say 100 watts/100ah battery but I have set up systems with 2x100ah batteries for every one 100W panel and conversely 2x100W panels for every 100ah battery depending on the circumstances. Of course most full sized panels are over 100W now, just makes for easier calculations.


As far as reserve isn't it the unwritten rule like 50% at least battery after three days autonomy what I'm thinking is 7020W of battery thats six 6v 195AH and 750W of solar panels as far as load thats really hard to figure would just have to watch and manage it.


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## LincTex

I have more solar capacity than battery capacity right now. 

I don't do a lot of long, drawn out (lights-on-all-night type of thing) power usage - - well, at least no heavy loads, I do run some LED lights all night but they do not draw much juice.

My main loads are heavy for short periods of time, like the Flour mill for 10 minutes, Radial arm saw for 10 seconds every few minutes for several hours, 4.5" hand grinder for 10 minutes per hour, etc. The battery bank draws fast and also charges fast. 

If I have no sunlight, I might have to run the diesel 12 volt generator (homemade) for a little bit, but if it gets that bad I make sure I have lots of other loads ready to go to making starting the engine and warming it up worth the trouble. Since I have an air compressor mounted on it I will typically also fill a big air tank with compressed air while charging the batteries.

Eventually I will have to add more deep-cycle batteries if I want to run a fridge (converted from a chest freezer) for any period of time, which is a future goal.

For now, one hours worth of diesel is a LOT cheaper than more solar panels and/or batteries (neither is cheap). Eventually I will add more, though.


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## Iron_Bran

*Good Advice*

I agree with this, and would like to add a little more theoretical thought...

In a full off-grid situation, like in a remote cabin, you are going to use a significant portion of the sunlight to power your electrical loads - with the leftovers going to battery charging.

Just because you generate 1200 Wh per day does not necessarily mean you are going to have that much energy in the battery when the sun goes down.

I often recommend that people OVER-size the solar array and UNDER-size the battery... and I'm a battery guy. The idea here is that your off-grid batteries are not like the AA cells you get at Walgreens, in that they only hold the energy you give them.

Solar is getting cheaper every day - so don't be scared to go big with the solar panels!

Check out these details on kWh usage for some common appliances (attached).



cowboyhermit said:


> 100ah 12V battery=1200Wh(watt hours)
> It really depends on the load and the amount of reserve capacity you want to have (length of time you can run without sunlight). In places with long nights in the winter like we have more battery bank per panel is recommended.
> In a theoretical situation a 100 watt panel would take 12hr to charge that 100ah battery however charging is not 100% efficient (not even close) but that is balanced by the fact that you never want to discharge a battery far enough to get that full 100ah out.
> 
> For most cases I would say 100 watts/100ah battery but I have set up systems with 2x100ah batteries for every one 100W panel and conversely 2x100W panels for every 100ah battery depending on the circumstances. Of course most full sized panels are over 100W now, just makes for easier calculations.


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## Iron_Bran

*Generator PTO*

Great plan here. One thing to consider is that your battery charger / inverter is going to be limited to about 80 Amps at the given battery voltage. Even if you have a 20 kW+ generator, the inverter can only pass through so much current. Size your battery based on the 80 amps per hour (at 12, 24, or 48V) so that you don't have to run your generator for more than 4 or so hours at a time!

Check out this inverter and system design that uses a balanced approach (solar, battery and generator working together)



LincTex said:


> I have more solar capacity than battery capacity right now.
> 
> I don't do a lot of long, drawn out (lights-on-all-night type of thing) power usage - - well, at least no heavy loads, I do run some LED lights all night but they do not draw much juice.
> 
> My main loads are heavy for short periods of time, like the Flour mill for 10 minutes, Radial arm saw for 10 seconds every few minutes for several hours, 4.5" hand grinder for 10 minutes per hour, etc. The battery bank draws fast and also charges fast.
> 
> If I have no sunlight, I might have to run the diesel 12 volt generator (homemade) for a little bit, but if it gets that bad I make sure I have lots of other loads ready to go to making starting the engine and warming it up worth the trouble. Since I have an air compressor mounted on it I will typically also fill a big air tank with compressed air while charging the batteries.
> 
> Eventually I will have to add more deep-cycle batteries if I want to run a fridge (converted from a chest freezer) for any period of time, which is a future goal.
> 
> For now, one hours worth of diesel is a LOT cheaper than more solar panels and/or batteries (neither is cheap). Eventually I will add more, though.


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## cowboyhermit

talob said:


> As far as reserve isn't it the unwritten rule like 50% at least battery after three days autonomy what I'm thinking is 7020W of battery thats six 6v 195AH and 750W of solar panels as far as load thats really hard to figure would just have to watch and manage it.


When it comes to alternative energy systems there are SO many factors like whether or not you have other means to charge the batteries, different usage patterns (some places I have setup have a near constant load others vary tremendously), what type of weather, latitude, etc. 
LincTex mentions a system with more solar than batteries, that makes a lot of sense especially if you have a reliable generator. Batteries will degrade much faster than panels so he can add capacity at a later time with less cost.
Iron_Bran makes good points too, time of day, efficiency of charging all play a role in making it more complicated
I have also had good luck with the reverse though, setting up a battery bank that can be charged multiple ways with no or minimal solar and then adding more solar later.:dunno:
Basically I think you have to figure out what you want in terms of load, reserve capacity in hours or days, etc and go from there. That is the best thing about these systems imo they are expandable and customizable

However, having said all of that your 6 batteries for 750 watts of panels falls somewhere in the range of most installations I worked with 100-150watts/battery


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## LincTex

Iron_Bran said:


> One thing to consider is that your battery charger / inverter is going to be limited to about 80 Amps at the given battery voltage. Even if you have a 20 kW+ generator, the inverter can only pass through so much current.


I don't charge through the inverter... 

I am using two LARGE Leece-Neville "555" alternators belt driven from a small diesel engine, with externally located rectifiers and regulators. Each is controlled independently, and can be run either as 12 volt or 24 volt units as needed, one or both.

See here for ideas on how I am doing it (mobile_bob is my hero) since it is easier to copy-and-paste links than to type:
http://www.microcogen.info/index.php?board=12.0

http://www.microcogen.info/index.php?topic=2930.0

http://www.microcogen.info/index.php?topic=2898.0

http://www.microcogen.info/index.php?topic=2924.0

I also have (on this rig) the ability to easily add a 6-rib (serpentine) belt-driven Harbor Freight 10KW generator head (3600 RPM) that I can remove or install in just minutes. The diesel engine runs at 1600 RPM when the HF head is spinning at 3600.

No, not the full 10KW - more like 4KW max from this small diesel, but I don't need that much power, just the clean 60HZ sine wave when I don't want to mess up my "capacitor run" induction motors (that don't like modified sine wave very much). Eventually, a "pure sine wave inverter" will handle those loads, but I don't have one yet.

I'm only burning about a pint/500ml of diesel per hour at a light/moderate load (usually) and about a quart/liter per hour under a heavier load (pretty seldom).

I also have an Indian-built "Listeroid" 6/1 diesel that will be a stationary plant sometime this next year. I still have lots of fencing to do first, though 

The only 24 volt inverter I have is a Trace DR1524 (1500 watts). Most of what I do runs from 12 volt inverters. (I have a bit of 24VDC powered equipment, though) The Listeroid will be making 24VDC power as well spinning a Marathon 120/240 60Hz gen-head at 1800 RPM.


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## unbill

Very well done.


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## LincTex

What ever happened to JeepHammer?


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