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I'd like to set up solar for my critical needs

 
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Thanks everyone for the input, especially the latest post by Sean!  I'm going to plug the Kill-a-Watt into the fridge for a few days to see what it's actually pulling.  

The furnace isn't a load I'm really concerned about since we only use it when we're on vacation.  We use wood heat most of the time...
 
pollinator
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Matthew Nistico wrote:

Phil Swindler wrote:Last March we installed a grid tied system on our roof...
The electric bill we paid for this last December was $11.53.  That was all just taxes and fees.  We haven't paid for any actual electricity since August.  If we didn't air condition, we wouldn't have paid for any electricity since April.
We don't have battery backup.  But, if you can pull that off with your budget, I would encourage you to go for it.



Yes, if you are looking for a whole-house system - very different than what the OP is proposing - then it is often very attractive to go grid-tied.  Glad that your own experience has been so good!  Batteries are great for self-reliance, but unless your power needs are very, very low, buying a suitably large battery bank can be cost-prohibitive.  Even in the best circumstances, batteries will certainly be the most expensive part of your system.  If I were to buy lithium batteries for my own small (3.8kW), whole-house system right now, enough to ensure off-grid capacity for my needs, they would cost at least twice as much as all other system hardware combined.

However, a word of warning to any newbies who might be reading this thread: your grid-tied mileage may vary!  If you're interested in grid-tied photovoltaics, then before even wasting your time researching other aspects of your system, look up what net-metering rate schedule is offered by your utility.  Without good net-metering terms, you may decide to go another way.  And those terms vary enormously from utility to utility, based on what your state government has forced them to offer.  I say "forced," because the general rule is that your utility really doesn't want you to generate power, even while you sell them the excess for cheap; they are invested in the traditional model of selling you electricity that they distribute from a centralized generation facility.

With growing federal requirements to transition to renewable energy, you'd think they might be happy for you to add grid-tied solar - for which they get to claim the federal renewable generation credits - to their system at your own expense, right?  Nope.  They are building they own solar farms.  So they intend to remain within the traditional model: they generate power centrally, albeit renewably, they control the distribution, you buy their power.

My own utility is switching from a very attractive net-metering schedule, to an almost-as-nice interim option, to just this month a new option going forward that is so unattractive it is practically punitive to the home generator.  How is that for boldly going into a renewable energy future?!  With a little luck, I should be grandfathered into the interim schedule for years to come.  But if I were to end up on the newer "punitive" rate schedule, it could be so bad that I literally would save little-to-no money even while generating most of my own power!  Yes, that bad.

The point is that net-metering can make or brake your plans for a grid-tied PV system.  If I didn't already have a solar system, and my only choice was the newer rate schedule, I might well consider investing that money somewhere else entirely.

Full disclosure: my own economic situation relative to utility bills is somewhat unique simply because I consume so little energy.  A more typical American household that consumes at least two, or maybe three, or even four times more energy than I do would likely still find at least some benefit to home generation, even under my "punitive" net-metering rate schedule example.



Matthew has some valid points.
Here in Kansas the power company has to do an even swap on what you produce vs what you use.  If you produce more than you use, they only have to give you 25 cents on the dollar and only up to what your taxes and fees total.  So, it doesn't make sense to have a system much larger than your average usage.
And, as of when we installed our system, battery backup was still prohibitively expensive.  I was cheaper for us to buy a small gas generator for when the grid goes down.
 
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Definitely check your kw requirements.

For fridge what we ended up doing was converting a full size standup 20cuft deep freeze using this:
https://www.amazon.com/Inkbird-Aquarium-Temperature-Controller-ITC-306T/dp/B07KC24CKD

This works so well because a standup deep freeze has about 3-4x the insulation of a fridge.  One of the biggest scams today with complaints about energy consumption and being eco friendly is refrigeration.  If there was actually committed concern about energy efficiency we would insulate fridge's the same as standup deep freezes and reduce electrical consumption of one of the most heavily power consuming and universal appliances in every single home by a factor of 8x.  The fact that you cannot purchase an actual fridge that is as efficient as converting a standup deep freeze is one of those indicators that corporations are only paying lip service to there being an energy crisis.

That turned our refrigeration power consumption down to around 380watts per day for fridge.

We switched to a passive propane wall furnace for heat and used dewalt shop fan to run super low speed to circulate air around the house which eliminated electricity power use for heat, sadly we had no wood fireplace option at that house.

We also swapped to propane on demand hot water heating and propane stove/oven, a special offgrid style one with pilot light and spark igniter that ran off a single d-cell battery so in one fell swoop we removed all electrical power requirements for heat, hot water and cooking.  Switched to LED lights for the house and that allowed us to run 2.8kwh per day (with 1.1kwh being the inverter's standby consumption).

Later when we went back with grid attached, I mentioned the transfer switch, which may be a good option for you, this is what was installed:
https://www.amazon.com/EGS107501G2KIT-10-7501G2-Detailed-Instructions-Flexible/dp/B005FQJD7K/

Each circuit can be individually flipped between different power sources and you connect your breakers in your main panel to the transfer switch lines individually so each switch controls a corresponding house breaker.  The transfer switch has breakers on each line, a few 20a and mostly 15a breakers.

As for batteries an expense, Canada being typically more expensive I got unbranded trojan t-105's for $200ea, they're 6v and 220amp hours, so for $3200 I got a 21kwh battery bank (useable around 10kwh).

This actually isn't the highest expense of a system although its a hefty one.  The canadian price for a 3500watt true sine outback inverter was $3700 which was actually my single highest expense.

That said I do highly recommend lifepo4.  Having used lead acid with the limited lifespan and charge limitations, you will get much more mileage and lifespan out of lifepo4 as well as allowing you to run successfully on 2hrs per day of sunshine rather than the 5 required to maintain lead acid.  Ultimately the cost per available useable kwh is about 2x the price as you can discharge much deeper with less damage on lithium.  The biggest selling point though is that you can charge in 2 hrs on a linear charge curve without the lead acid impedance as you approach full.  This is invaluable as you cannot dictate more sunshine and no amount of solar panels creates a longer period of solar activity if it just isn't there.  Being able to fully recharge your system in 2hrs of sun just can't be beat.

That said, if I were doing everything over again and didn't have access to micro hydro I would probably do a biogas system which uses a fraction of the footprint, provides gas for heating and cooking and water and fuel for generator and potentially vehicle as well and is just capturing existing methane production from biomass breakdown.
 
Sean Wood
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Also, just for some references, this is a place I've purchased some items online and tends to be one of the better priced online solar hardware resellers.

https://www.altestore.com/store/inverters/hybrid-inverters/outback-power-fxrvfxr-series-inverter-chargers-p40835/#OUTVFXR3648A1

Thats the inverter that I purchased in canada for $3700 while its $1900 in the states.

As for Lithium batteries:

https://www.altestore.com/store/deep-cycle-batteries/lithium-batteries/simpliphi-power-smart-tech-lithium-batteries-p40602/#SIMPHI3_8-48V

I believe simpliphi gives a 10,000 cycle warranty (and 10 years) so thats a useable 3kwh of battery power at a c/2 charge rate for $2500, this would require 6kwh of lead acid to get the same useable power:

https://www.altestore.com/store/deep-cycle-batteries/flooded-lead-acid-batteries/crown-fla-parent-code-p40868/#CRWCR-235FLA

Those are $170, decent price, you'd need 8 in a string to do 48v so you're looking at $1360 but you'd have about 5.5kwh of useable power, so almost 2x of the simpliphi needed bringing you to a $5k cost for the lifepo4 vs $1360 for lead acid for similar usable battery power (about 4x the price for lithium).

But you get about 3-4x the lifespan and that 2 hr charge time from the lifepo4's.



 
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WOW! Lots of informative responses. It’s interesting how everyone does a energy system differently. I’ve built them many ways from calculating carefully to winging it with what I can toss together.
Currently I have a cargo trailer with 8@200 watt panels (4 on the roof and 4 hanging in the side on hinges). It occurred to me that using one of the trailer moving dollies available I could easily move it a couple times a day for optimal solar gain. Perhaps if you don’t want to cut down the tree you could park a solar trailer. Another advantage is no electrical permit is need we at all. And it’s mobile. Do you have a sunny spot to park a trailer?
If I had grid power I’d be tempted to simply build a system with whatever I could scrap together then simply run what I could power on it. But calculating and planning carefully is fun too.
 
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Mike, we did something similar several years ago. I don't know if I can add anything to the good information you've already gotten here, other than another example. So, here's what we've got, how it works, and what I wish we'd done differently.

The goal was to put my chest freezer and a fridge on it's own solar power system. I used a Kill-A-Watt meter to measure how much electricity these appliances used so I could size my system. I found the panels on craigslist and the rest of the system we bought new. The freezer and fridge are both AC, so we needed to include in inverter in our system.

The main components:
- 3 solar panels: 345 watts each. Wired in parallel = 1035 watt array
- MPPT charge controller: Outback FM60
- 6 batteries: 235 AH 6-volt deep cycle batteries
     -- pairs connected in series to create 12-volt system
     -- strings connected in parallel to total 705 amp-hours
- inverter: 1000 watt (2000 watt surge) pure sine

These are the things people focus on first, but there are a bunch of smaller components that are just important. Here's the wiring diagram I made that helped us visualize the system as a whole.



Two notes:
 1. Some folks put the entire system on one earth-ground. We did the array separately as per manufacturer's installation instructions.
 2. We had 25 feet between panels and battery bank. Keeping this distance short helps with wire size and cost.

One thing I'm very glad we did was to set up the panels with a rack on the ground rather than on a roof.
 1. Easier to clean!
 2. Dan was able to make the rack adjustable. This has helped a lot! The following photos are from my blog.

Angle adjusted for June

Angel adjusted for January

One thing I wish we'd done differently was to invest in a larger battery bank! Budget was tight, but in hindsight, I should have scrounged the money from somewhere for batteries. We currently have 705 amp-hours, which is only about a day and a half to two day reserve in extremely cloudy weather for the two appliances. Our charge controller does great at optimizing what the panels make, so that we can fill the batteries on a cloudy day if it's bright enough. But when the weather is dark as it often is in winter, I find I sometimes have to plug the system back into the grid.
 
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Dianne Justeen wrote:
My husband is the one investigating solar.  Seems like the priciest part is the batteries.  He's doing further research on DIYing the battery bank.  Can't be super-helpful on that one yet but it may be possible and much more cost efficient.  Anyone know anything about that?  

We'll need enough to power the well pump and the bare essentials for at least several days with minimum recharging if the weather is bad.  Considering some wind powered charging since we have fairly steady wind but yet to tackle looking into that.  We're guessing it could be tied into the solar setup but could be wrong.


Scroll back to post #8 of this thread.  The 48V system outlined is what you would need to run a 240VAC well pumpl

I think anyone that thinks they can make or rejuvenate batteries is delusional.  Tried to rejuvenate a dead battery once with the EDTA method.  All I accomplished was the destruction of a good pair of pants.  Good batteries are not cheap, and cheap batteries are not good.  You get what you pay for!

Most people I've seen online have been disappointed with wind generation.  Unless you are on the beach, or a mountain top winds are not high enough to generate meaningful power.  Keep in mind that most wind generators make zero power below 10MPH, and the curve for making more power is very sigmoidal.

 
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You sound to have a good understanding! You are correct batteries and inverter would need to be housed inside. Lithium ion batts are better than lead acid or refurbs. The more batteries the better as you have more saving capacity. You’ll have to cut more trees than you think. Apparently even one small shadow reduces the capacity of the panel by quite a lot. I recommend doing a search online for your local solar supplier. Having a certified installer is better than attempting the job yourself. Also, buying new from a supplier affords you warranty and support if something comes up.
You can find details on electricity consumption on all your appliances online by typing the model number in a search. Most appliances are far more efficient than you would think.
We have 16 panels, 8 batteries, and two inverters. 3 chest freezers and a fridge run daily and overnight we loose only 10% charge in a 10 hours. We have many appliances running throughout the day and we don’t skimp out on conveniences. For cloudy days we run a generator for 1-2 hours maximum and we could go probably two days with no sun or generator help, but this is not recommended if you want to maximize the life of your batteries.
 
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Hi Mike,
You've bit off a big project. I started work on a similar system but you're quite a bit more ambitious than I was.  Others have run through most of the practicalities. I was going to mention line loss from the panels to your house but someone beat me to most of it. Same with how fast you can charge different batteries. I can, however, add a little to line loss on your runs from the barn to the house. In electrical circles it's called voltage drop and it's pretty much solely based on how many amps and what size wire. A 10A load running over 10A wire is going to lose as many volts for a 12v system as for a 120v system. But you'll get 10x the power through on the higher voltage system. That's why panels and batteries are commonly run in series.
For example your initial 6 330 watt panels on the barn all in series. (my 260W panels are 37V open-circuit so I'm using those numbers.)
First off, I'd guess you won't get a straight shot. Estimate it's probably 250' of wire. (Might be optimistic)
The panels will, under laboratory conditions make 222V @8.9A
Run that the 250' to the house using #10 wire and you'll lose 5.1V or around 45 watts
Using #12 wire you'll lose 8.2v, or 73W
Using #14wire you're at 13V or 116W
however, one leaf or patch of snow on one of those panels will cut your production significantly. Not sure if it's more or less than half.
So obviously having panels close to the house would be better if you had sun exposure.
I'm not sure how much useful sun you'll get in WI. I'm in CO and have trees running north-south on both sides of the house. I've been getting about 1kwh per day out of 520w of solar panels. You'll need more than you think.

Definitely invest in a good clamp ammeter like a fluke 275 so you can measure the startup currents on stuff. Kill-a-watt meters are good two but for two things: Neither of mine will tell me startup current and they only measure Watt-hours and not Volt-Amp-Hours. Watts don't actually tell you how much is being drawn from your panels or batteries. Watts is only how much energy is going to useful work but not how much is going toward inefficiencies. And these can be significant for anything with a motor, which is most of what you listed. Your kill-a-watt will give you power factor. Basically a power factor is the percentage of total energy that's producing work. So if your freezer has a PF of 70, which is completely within the realm of possibility, the watts you're measuring toward watt-hours is only 70% of the total power you're using. Most computer and cell phone chargers are abysmally low, as well. I think my computer one has a PF of 52.
Personally my system is completely isolated from any or my house wiring. I have to unplug an appliance from the wall and plug it into my off-grid system. I've thought of running dedicated wires from the inverter to a different-colored outlet next to strategic appliances I might want to power. If you're wanting to integrate your off-grid system into house wiring you need to invest in transfer switches and a lot of knowledge in how to set them up safely.

When I was first starting to tinker with this I was trying to come up with a system that I could expand. Unfortunately you want your batteries to be matched (no pairing old ones with new) or you run the risk of your batteries discharging each other. I'm not sure how big of a problem this really is. I wanted to go with Lifepo4 batteries since they claim a much longer lifespan and greater depth of discharge. Unfortunately in the end I decided that they were too expensive for the amount I'll use them plus they're a relatively new technology. Lead-acid is a much more mature technology. I figure when I get ready to upgrade to Lifepo4 they'll have gotten cheaper the tech will have matured. Sure they claim 8-10k cycles now but will they? Sort of like how 10yr LED bulbs burn out in a few months or a couple years now.
In the mean time I decided to go with a pair of Trojan T-105's (6V, 220Ah). They'll run my chest freezer for about a day and a half without sun. The freezer draws 68W when running but when first turned on it draws in excess of a kW. My 1200W inverter can't handle that without using its soft-start setting. Or, maybe more likely, my batteries don't like putting out 100A to power it. Putting another set of batteries in parallel to these might make it work better. I don't know.
Whenever the time comes to upgrade I'll  probably just start another system based on everything I've learned here. For instance I'd want a 24 or 48V system for anything running an inverter but I have lots of stuff that runs off 12V. If I don't have to run an inverter that's a lot of power savings.
For instance you could have one system in your barn for barn loads and one system for your house.

Charging you're wife's Prius has its own issues. I assume it has an AC charger but the batteries need DC. Going DC -> AC -> DC will have a lot of loss. If you can find a DC charge controller for it you'll be ahead of the game. The author of http://aprs.org/my-EVs.html has experimented some with charging Prius's off solar and may have some insights on how to best do that conversion.
You might be able to use the Prius as a generator for recharging your batteries when the sun isn't shining.

Personally I think I'd recommend making a smaller system to power one load and trying it out for a year or two before throwing a whole lot of money at it. Otherwise, keep doing a lot of research so you get it right (don't get it too wrong?) the first time.

Oh, one more thing. Working with high voltage DC is a bit more dangerous than working with AC. If you accidentally grab onto an AC wire there are 120 times a second when it has 0 volts on it and thus give you a chance to let go. DC gives you no such reprieve.

 
Sean Wood
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Daniel Kaplan wrote:Hi Mike,
You've bit off a big project. I started work on a similar system but you're quite a bit more ambitious than I was.  Others have run through most of the practicalities. I was going to mention line loss from the panels to your house but someone beat me to most of it. Same with how fast you can charge different batteries. I can, however, add a little to line loss on your runs from the barn to the house. In electrical circles it's called voltage drop and it's pretty much solely based on how many amps and what size wire. A 10A load running over 10A wire is going to lose as many volts for a 12v system as for a 120v system. But you'll get 10x the power through on the higher voltage system. That's why panels and batteries are commonly run in series.
For example your initial 6 330 watt panels on the barn all in series. (my 260W panels are 37V open-circuit so I'm using those numbers.)
First off, I'd guess you won't get a straight shot. Estimate it's probably 250' of wire. (Might be optimistic)
The panels will, under laboratory conditions make 222V @8.9A
Run that the 250' to the house using #10 wire and you'll lose 5.1V or around 45 watts
Using #12 wire you'll lose 8.2v, or 73W
Using #14wire you're at 13V or 116W
however, one leaf or patch of snow on one of those panels will cut your production significantly. Not sure if it's more or less than half.
So obviously having panels close to the house would be better if you had sun exposure.
I'm not sure how much useful sun you'll get in WI. I'm in CO and have trees running north-south on both sides of the house. I've been getting about 1kwh per day out of 520w of solar panels. You'll need more than you think.

Definitely invest in a good clamp ammeter like a fluke 275 so you can measure the startup currents on stuff. Kill-a-watt meters are good two but for two things: Neither of mine will tell me startup current and they only measure Watt-hours and not Volt-Amp-Hours. Watts don't actually tell you how much is being drawn from your panels or batteries. Watts is only how much energy is going to useful work but not how much is going toward inefficiencies. And these can be significant for anything with a motor, which is most of what you listed. Your kill-a-watt will give you power factor. Basically a power factor is the percentage of total energy that's producing work. So if your freezer has a PF of 70, which is completely within the realm of possibility, the watts you're measuring toward watt-hours is only 70% of the total power you're using. Most computer and cell phone chargers are abysmally low, as well. I think my computer one has a PF of 52.
Personally my system is completely isolated from any or my house wiring. I have to unplug an appliance from the wall and plug it into my off-grid system. I've thought of running dedicated wires from the inverter to a different-colored outlet next to strategic appliances I might want to power. If you're wanting to integrate your off-grid system into house wiring you need to invest in transfer switches and a lot of knowledge in how to set them up safely.

When I was first starting to tinker with this I was trying to come up with a system that I could expand. Unfortunately you want your batteries to be matched (no pairing old ones with new) or you run the risk of your batteries discharging each other. I'm not sure how big of a problem this really is. I wanted to go with Lifepo4 batteries since they claim a much longer lifespan and greater depth of discharge. Unfortunately in the end I decided that they were too expensive for the amount I'll use them plus they're a relatively new technology. Lead-acid is a much more mature technology. I figure when I get ready to upgrade to Lifepo4 they'll have gotten cheaper the tech will have matured. Sure they claim 8-10k cycles now but will they? Sort of like how 10yr LED bulbs burn out in a few months or a couple years now.
In the mean time I decided to go with a pair of Trojan T-105's (6V, 220Ah). They'll run my chest freezer for about a day and a half without sun. The freezer draws 68W when running but when first turned on it draws in excess of a kW. My 1200W inverter can't handle that without using its soft-start setting. Or, maybe more likely, my batteries don't like putting out 100A to power it. Putting another set of batteries in parallel to these might make it work better. I don't know.
Whenever the time comes to upgrade I'll  probably just start another system based on everything I've learned here. For instance I'd want a 24 or 48V system for anything running an inverter but I have lots of stuff that runs off 12V. If I don't have to run an inverter that's a lot of power savings.
For instance you could have one system in your barn for barn loads and one system for your house.

Charging you're wife's Prius has its own issues. I assume it has an AC charger but the batteries need DC. Going DC -> AC -> DC will have a lot of loss. If you can find a DC charge controller for it you'll be ahead of the game. The author of http://aprs.org/my-EVs.html has experimented some with charging Prius's off solar and may have some insights on how to best do that conversion.
You might be able to use the Prius as a generator for recharging your batteries when the sun isn't shining.

Personally I think I'd recommend making a smaller system to power one load and trying it out for a year or two before throwing a whole lot of money at it. Otherwise, keep doing a lot of research so you get it right (don't get it too wrong?) the first time.

Oh, one more thing. Working with high voltage DC is a bit more dangerous than working with AC. If you accidentally grab onto an AC wire there are 120 times a second when it has 0 volts on it and thus give you a chance to let go. DC gives you no such reprieve.



Daniel,

I myself ran some DC loads on my 48v system.  12v is definitely the easiest to get equipment for as lots of RV stuff (such as a low wattage DC water pump that I used for our water pressure boost) run on 12v.

The best thing about anything motor based thats running DC motors is you avoid that massive impedance spike from startup as well.  AC motors generate impedance when they're starting because their cycle isn't matching the 60hz necessary for them to run optimally, DC motors are linear in their power consumption that way in that you don't get insane impedance spikes when they're under load.

For example my wife had a kitchenaid AC motor mixer, 350 watts.  When making bread though, once the dough was starting to stiffen up the wattage would spike up to around 1500 watts due to the impedance that was happening because the motor was slowing down too much and not running at its optimal 60hz to align with the AC power.  We bought her a more expensive kitchenaid specifically with a DC motor.  While it runs on AC it has a dc converter for running the motor which maintains a steady 350 watts consumption straight through from start to finish, even under load.

AC motors are very clever but from a power perspective are very inefficient.

That wasn't what I started wanting to mention though.  For my system what I did was use DC to DC buck (or step down) converters for my DC power loads.  DC to DC step down converters may consume some power on standby but it is incredibly low, nothing like maintaining an AC inverter.

They're really cheap too.

Due to my system being 48v which can spike up to 62v when doing equalization charges on my t-105's I purchased this converter:

https://www.amazon.ca/Converter-DROK-Adjustable-Regulator-Transformer/dp/B08LPVWX74/

I actually configured that to run at a steady output of 48v, then you can use smaller gauge wire to run dc wire through the house to various loads and then use one of these at load sites:

https://www.amazon.ca/UCTRONICS-Numerical-Stabilized-Converter-Adjustable/dp/B01LWXAC5E/

Those are handy with a dial and output amp setting so you can get clean consistent DC power and step it down to targeted voltages at specific locations (usually 12v) but you could do things like swap out your dc adapters for TV's and laptops and just create your own DC pigtails and set your DC output voltage to match your power adapter and save alot of inefficiency in converting back and forth.

So just wanted to mention that, its a way to use the 48v setup and still power 12v loads.




 
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https://www.engineeringtoolbox.com/wire-gauges-d_419.html

https://faroutride.com/wire-calc/

https://www.nfpa.org/~/media/Files/Code%20or%20topic%20fact%20sheets/NECAmpacityWorkflow.pdf
 
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Michael Qulek wrote:[
Scroll back to post #8 of this thread.  The 48V system outlined is what you would need to run a 240VAC well pumpl

I think anyone that thinks they can make or rejuvenate batteries is delusional.  Tried to rejuvenate a dead battery once with the EDTA method.  All I accomplished was the destruction of a good pair of pants.  Good batteries are not cheap, and cheap batteries are not good.  You get what you pay for!

Most people I've seen online have been disappointed with wind generation.  Unless you are on the beach, or a mountain top winds are not high enough to generate meaningful power.  Keep in mind that most wind generators make zero power below 10MPH, and the curve for making more power is very sigmoidal.



Thanks for the insight. You confirmed what my husband thought about needing a 48V system. As will be obvious by my lack of electrical knowledge, this is me not my husband writing this.

We experienced a lengthy loss of power during Superstorm Sandy and learned some valuable lessons.  In a situation like that, unless you've stored a ton of fuel, you will be unable to get the gasoline or propane refilled to keep running a generator.  Propane fireplaces designed for ambiance not household heating will bang through the fuel and run out quickly, as our former next door neighbor can attest.  At that time we had municipal water that kept flowing, but I know water is a priority.  What I really missed when the electric was out was hot water and heat.  Even though it was autumn, the weather turned very cold.  Not cold enough to freeze the pipes but cold enough to be uncomfortable.  We had an oil furnace/water heater that would have used very little electricity to run, but was hard wired.  We've since had it adapted so it can be plugged into a generator to run long enough to warm up the house and get all the bathing and washing done without lugging pots of water from the stove.  A propane camping stove with an adequate supply of propane is a must.  Everyone seems to lose their minds about the refrigerator, but that's really not a huge issue for us.  If it's cold out - put the food outside.  In the warm weather, there's probably not a lot of bulk storage anyway.  Invite the neighbors and have a feast.  Full freezers kept closed only need to be turned on occasionally to stay frozen.  Lights aren't as big a deal for us as for some people.  We've stayed in a travel trailer off-grid for a couple of years prior to beginning the build and used battery powered lanterns.  There's no need to light more space than is currently occupied.  A bit of task light for cooking, washing up and reading, playing games, etc. is appreciated.  I'm old enough to have lived prior to being connected 24/7 so if my device of choice dies, I will live.

I believe there are well pumps that can be wired either 120 or 240?  We chose a Grundfos pump that is wired with the pressure tank 120 on its own 20 amp breaker. Our well is 113' deep so while I wouldn't want to have to hand pump it, it's not the 300'+ some people deal with. (Again, this is my recollection - my husband may roll his eyes at my stupidity.) Thought it might be easier to run on a generator or battery system that way.  Our place is very well insulated and has a wood stove for heat.  We have maybe 2 weeks max where it stays hot at night in summer.  Otherwise there's no need for a/c although running a dehumidifier might occasionally be nice. There's a propane on-demand water heater that uses very little electricity.  The cooking stove is propane but we can cook on the woodstove if we needed to conserve propane.  We have an inexpensive tiny refrigerator and plan on putting the money we saved on not buying a DC adaptable one towards building a root cellar.  When we poured the slab, we put in a large pipe for a "cool cupboard" - the idea is from David Holmgran's Retrosuburbia.  We're still in the finishing stages so the kitchen isn't done yet.

We've tried to minimize how much energy is needed to run the place because when we bought the land, there was no electricity there.  It has since arrived as we began building and we are grid-tied.  But we didn't see any reason to expand our usage and try to view the grid as a convenience, not a necessity.  Our power line powers 2 houses on a very remote rural road.  If a storm takes out our electricity, as has happened several times already, it could be some time before we get power back.  

They don't work well in our climate and are way too expensive, but I've always been fascinated by Earthships.  I can see the people reading this giving the "look" as I write that!  We kept part of the philosophy of designing not to need a ton of energy inputs in the first place rather than trying to provide enough off-grid energy to power an on-grid house. I realize this isn't the case for everyone but our concern isn't running a ton of stuff, it's more that the sun don't shine well in winter. And since we are just below a ridge in what are considered "mountains" on the east coast we do get pretty consistent wind, although maybe not good enough for any significant generating.
 
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Most of this discussion is over my head but I want to add two teeny points. One is that we put up our off-grid system in 2009, changed to bigger and better batteries about seven years later and added two panels but several months ago my husband discovered that the cables connecting the batteries to each other were not working right, and were not equal. So he bought a new set of bigger and better cables, made sure they were hooked up right and equal, and--the difference has been amazing. In how much the voltage drops after a load, in how quickly the panels recharge the batteries.
The other is that I agree that in much of the country, including here, there is not enough wind to be worth installing a windmill. But another option in some places is microhydro. I visited someone higher in the mountains here who had a hybrid solar-microhydro system; they'd spent a fair amount of money but it was a good system. Note that with either wind or water, with a turbine, you can't deflect excess power like you can with a charge controller with solar-you have to bleed it off somehow. Those people I visited had an electric heater next to the battery bank that would run whenever that happened--I guess fortunately water power is maximized in winter and no difference day/night so it would mostly complement the solar.
Another thought. There is a lot of talk about the various options and whether they are cost effective, including whether to do this at all. I say, the time is coming when the grid becomes unreliable and perhaps goes down altogether, and it will no longer be possible to get solar panels--they are not a backyard project--they're high-tech and require high amounts of power to build. So it's up to households and communities to set themselves up with minimal power systems. Here I draw on my own experience: the first five years I lived in WV, in the late '70s and early '80s, I had no electric--and really didn't mind. But I was a childless single hippie, living on nothing. For light in those days I used a kerosene lamp. Those smell, the wicks always need trimming, and they're a fire hazard. Kerosene is also a fossil fuel. Now we use LED lights that don't smell or leak and that shed plenty of light while drawing a tiny amount of power. Here's the punchline: if you decide it's cheaper to stick with grid power, and things come crashing down, you'll be using candles. On these long winter evenings... So yes, you do need to configure your system so you can add to it later, but put a small system up NOW.
 
Mike Haasl
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Sean Wood wrote:That said, if I were doing everything over again and didn't have access to micro hydro I would probably do a biogas system which uses a fraction of the footprint, provides gas for heating and cooking and water and fuel for generator and potentially vehicle as well and is just capturing existing methane production from biomass breakdown.


I don't want to take this thread off topic since it's full of awesome information.  But I am interested in this as an alternative.  Might you be able to start a new thread to describe what you'd have in mind and then we can talk about it over there?  Thanks!!
 
Dianne Justeen
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Mary Cook wrote:
Another thought. There is a lot of talk about the various options and whether they are cost effective, including whether to do this at all. I say, the time is coming when the grid becomes unreliable and perhaps goes down altogether, and it will no longer be possible to get solar panels--they are not a backyard project--they're high-tech and require high amounts of power to build. So it's up to households and communities to set themselves up with minimal power systems. Here I draw on my own experience: the first five years I lived in WV, in the late '70s and early '80s, I had no electric--and really didn't mind. But I was a childless single hippie, living on nothing. For light in those days I used a kerosene lamp. Those smell, the wicks always need trimming, and they're a fire hazard. Kerosene is also a fossil fuel. Now we use LED lights that don't smell or leak and that shed plenty of light while drawing a tiny amount of power. Here's the punchline: if you decide it's cheaper to stick with grid power, and things come crashing down, you'll be using candles. On these long winter evenings... So yes, you do need to configure your system so you can add to it later, but put a small system up NOW.



That's one of our thoughts.  Also, thanks for the feedback about wind/micro-hydro.  Our plan is for solar and batteries which can be added to later.  As I said before, my experience is that there's a minimum threshold that once met provides for enough power to live well.  Above that is a bonus but below that can be very difficult or at least a pain.
 
Dianne Justeen
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Mike Haasl wrote:

Sean Wood wrote:That said, if I were doing everything over again and didn't have access to micro hydro I would probably do a biogas system which uses a fraction of the footprint, provides gas for heating and cooking and water and fuel for generator and potentially vehicle as well and is just capturing existing methane production from biomass breakdown.


I don't want to take this thread off topic since it's full of awesome information.  But I am interested in this as an alternative.  Might you be able to start a new thread to describe what you'd have in mind and then we can talk about it over there?  Thanks!!



If you do start a thread on that I'd be interested in following that as well.  So please post a link to it here.
 
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Michael Qulek wrote:
I think anyone that thinks they can make or rejuvenate batteries is delusional.  Tried to rejuvenate a dead battery once with the EDTA method.  All I accomplished was the destruction of a good pair of pants.  Good batteries are not cheap, and cheap batteries are not good.  You get what you pay for!



Just for clarification, the idea wasn't to build the batteries, it's to put together the battery bank from the cells and the BMS.
 
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Dianne Justeen wrote:

Mike Haasl wrote:

Sean Wood wrote:That said, if I were doing everything over again and didn't have access to micro hydro I would probably do a biogas system which uses a fraction of the footprint, provides gas for heating and cooking and water and fuel for generator and potentially vehicle as well and is just capturing existing methane production from biomass breakdown.


I don't want to take this thread off topic since it's full of awesome information.  But I am interested in this as an alternative.  Might you be able to start a new thread to describe what you'd have in mind and then we can talk about it over there?  Thanks!!



If you do start a thread on that I'd be interested in following that as well.  So please post a link to it here.



I figured there must surely be existing threads on this topic.  Do searches for "biogas," "gasification," and "pyrolysis."  The last term gets you the most results, of which these threads looked like they might be appropriate to add on to:

https://permies.com/t/14425/Biomass-gassification
https://permies.com/t/29549/Gasifiers-Reviews-Compare-Expereince
https://permies.com/t/19954/Charcoal-Gasification
https://permies.com/t/142791/Lots-questions-relationships-Charcoal-Making
 
Michael Qulek
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Just for clarification, the idea wasn't to build the batteries, it's to put together the battery bank from the cells and the BMS.

OK, that is good to know.  I have seen other posts on other sites, where there were people actually advocating cutting batteries open, scrubbing plates clean, then re-assembining them.  There was even discussion about casting new plates.

One of my other hobbies is bullet casting, so I have a lot of experience with molten lead.  One of the critical warnings is that battery lead contains additives like arsenic, that upon melting separates from the lead.  If the arsenic waste gets wet, it produces deadly arsenate gas.

So, I tend to recoil away from anybody that mentions battery reclamation.
 
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Years ago I helped a friend wire in a manual transfer switch for the critical circuits (lights, refrigerator, freezer, stove, oil-heater control, and kitchen wall sockets for microwave and a cell phone charging station).  You can get those cheaply.  The automatic switchover at the time cost a lot of money, but you can check on those as well.  I liked one of the previous posters ideas about having a toggle switch so you can flip things from grid to solar, but I have never seen a UL approved circuit like that.  Whatever you do just make sure that it is approved for your area and safe so that you do not get tripped up with a future inspection.  Anyway, instead of having to yank plugs for a changeover, a single switch is a lot easier, and is why I hooked it up for a friend for his generator.
 
Mike Haasl
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I've been watching the shadows on the barn this week (when the sun is out) and I'm not feeling optimistic.  Below is a picture from the barn with my camera at the bottom edge of where a panel would be (just above the doors) at 10am.  So I think I'd have to cut down many dozens of trees to get sun on the barn.  Despite how high and sunny it seemed, it's not as sunny as I thought :(

My other option would be to attempt to attach panels at the top of my greenhouse.  This is likely pure folly and the sooner the experts tell me to drop the idea, the better.  The ridge of the greenhouse is 18' high.  The north side is a metal roof, the south side is two layers of poly film.  I could redesign the top area to support panels but once they're up there (which would be a hell of a chore), they'd be very hard to work on.  Just to get them up there I'd have to remove the glazing.  But, the greenhouse peak gets a solid 4 hours of full sun, with 1/2 hour of partial shade at either end of that.  And I could add 45 minutes of sun by cutting down the wife's favorite maple tree in the back yard.
Jan-9-sun-hitting-the-barn-at-10am.jpg
Jan 9 sun hitting the barn at 10am
Jan 9 sun hitting the barn at 10am
Maple-tree-is-the-fat-shadow-hitting-the-greenhouse.jpg
Maple tree is the fat shadow hitting the greenhouse
Maple tree is the fat shadow hitting the greenhouse
 
Matthew Nistico
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Mike Haasl wrote:I've been watching the shadows on the barn this week (when the sun is out) and I'm not feeling optimistic.  Below is a picture from the barn with my camera at the bottom edge of where a panel would be (just above the doors) at 10am.  So I think I'd have to cut down many dozens of trees to get sun on the barn.  Despite how high and sunny it seemed, it's not as sunny as I thought :(



It is for sure a necessity of PV power arrays that they get some direct sun.  Shoehorning a solar system into a marginal sunlight situation may simply not be cost effective at the end of the day.  At least during the winter, which is about when you are concerned, clearly.

While it is hard to give meaningful advice without better knowledge of your property, I can think of two (hopefully) useful things to say.  First, do the math and figure out if using your solar system to power your desired appliances 8 or 9 months out of the year is still worth it.  Perhaps it is, and you can just count on either 1) switching those appliances over to grid power during the deepest winter months; or 2) if you indeed go with a PV system incorporating significant battery storage, occasionally pulling out a gas generator to top off your batteries during those same months whenever the solar array isn't keeping up with the load.  You might find that you still end up far enough ahead, financially, to justify the capitol investment in the system.  Plus, you'll have added a degree of self-reliance to your living situation.

Second, consider what has already been suggested somewhere in this thread about building a solar cart that you could move from spot to spot on your property as the seasons shift.  There must be somewhere on your property that gets sunlight even in the winter.  Seems to me the questions would be 1) is the most desirable winter location accessible and flat enough to park your solar cart?  2) how would you move the cart around - by hand?  pulled by a small tractor?  3) are you willing to possibly kill some grass on the spot of your summer location?  or if not, are you willing to move the cart during the grass-growing months at least once a week between different locations?  4) are all potential cart locations during all seasons within reach by extension cord to the appliances you wish to power?
 
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If shadows are going to be a problem, then I'd say go with the ground mount I mentioned above.  You purchase a high-voltage charge controller, then wire all the panels in series.  The higher the voltage, the less loss there is for long distance power transmission.  Let's say you mounted six 30V grid-tie panels in series, to get 180VDC.  You could position the array almost 200 feet away with only 2% voltage drop using standard 10 gauge solar cable.  Further if you wire more panels in series.

Use this voltage drop calculator to determine what happens.
https://www.calculator.net/voltage-drop-calculator.html

The higher end controllers have Voc limits of 200V, 250V, 300V, and even 600V; the price does go up as the voltage limit goes up.  Just make sure the winter low temperature is accounted for in your calculations.  Here's a link to Midnight Solar's string calculator.  Like the voltage drop calculator above, you just plug in the panel specs and your winter lows, and the the calculator determine what is OK.
https://www.midnitesolar.com/sizingTool/index.php

Don't give up!  You just need to make some design updates to make it work!
 
Ebo David
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You might be able to estimate how much sun you get compared to how much is maximal, but I would ask -- if you got 50% of the available electricity in the middle of the winter, would that be enough for what you actually need or can use?  If you have electricity there already, then it would be simply shaving off what you actually use.   Sometimes the perfect is the enemy of the good enough.  Also, I agree it will be a PITA to work on, but how often do you think you will need to be up there working on it?  Once every 2 to 4 years?  How long will the plastic film last, and need to be replaced.  If you do add solar to it, then you can move the plastic attachment lower down (wiggle wire maybe?).

BTW, I know of folks that just assume that their greenhouses will not be functioning either in the dead of winter, or the hottest parts of the summer.  It does not have to be perfect to give you a tangible benefit.  That said, there is such a things as a cost/benefit, and only you can decide where that line is.
 
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The sunniest spot on the property is where the greenhouse is.  So if I used a cart or ground mount it would have to be in front (south) of the greenhouse.  I'll check how the sun hours are down low at that spot.  
 
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Mike Haasl wrote:The sunniest spot on the property is where the greenhouse is.  So if I used a cart or ground mount it would have to be in front (south) of the greenhouse.  I'll check how the sun hours are down low at that spot.  


Looking at your shadow pic of the greenhouse, it looks like the best position for a ground array is that left-hand corner just outside the fence.  Ideally, if the corner of the fence could be relocated, the spot inside the left-hand corner looks a bit better.  I don't believe a moveable cart is going to be able to make the levels of power that a full homestead is going to require.  I still think a ground mount is your best option.

Even if that area does not get sun until after 10:00am, what are the solar resources like later in the day?  With just one 1500W array, I'd think you could easily make ~3.5kWh of power from say 10:00am till 1:00pm.  More if you are out there rotating the array to track the sun.  Testing one of my own 1kW arrays, I found I could make 5 sunhours of power per day in February, by array tracking.  BTW, my single-pole array design does not have a motor.  I track the sun just by walking out and rotating the arrays by hand.  Hillbilly solar tracking.  Also, the light leaking through bare trees will be greatly diminished, but not zero.  You might still limp on with about 500W while bare-tree shadows are flickering across the panels.  



 
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It's sunny today so I'm trying to get an idea how good that area is every 30 minutes throughout the day.
 
Ebo David
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I wonder if there is some sort of image processing/model that would compare the area in shadow on your roof throughout the day -- and use that to estimate the degradation in PV efficiency.  I do not have time to research that now, but of you have time to dig on the net and find some potential programs I'll break away a little time to check them out.  It will of course require a series of photos all from the same place if not also orientation (but I can probably adjust for that).  Let me know if that is of interest.
 
Daniel Kaplan
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My dad has an app on his phone that you can point at the sky and will tell you the path of the sun at different times of year. I wonder if that would let you analyze different spots around the yard quickly. Probably direct observations is better, though. Direct observation with a small system is probably better yet.
 
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I've used one of those too and they work.  It is a bit tricky if you can't stand where the panels will be (like up on the greenhouse)
 
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