Power Generation General

[Lou Sassle]

A fun thing people always seem to forget is the disadvantages of having a generator. Generally speaking if the power is out for more than a few days it'll start to put a target on you and your home. The longer the power is out the bigger the target will be.

Great care should be taken with how loud your generator is, where you located it and any visible signs you have power.

An easy fix for noise is to buy a commercial silent generator. An additional muffler can be added to most of them. Build a heavily insulated box with no lid to stick around the generator to direct the sound into the sky. Suddenly a generator that was already 50-60db underload can't be heard 25' away. It'll be even quieter if you can hide it in the trees away from your home.

Now you have the other major problem. Looking like you have power. If your lights are on at night with your TV on and surround sound it'll be obvious you're getting power from somewhere. You'll need to blend in with the other powerless. Black out some of your windows. Unscrew the bulb in your fridge. Tape over LED indicators. You shouldn't be able to tell you have power from outside your home no matter the time of day or how quiet it is.

If you've done everything just right you'll appear to have no power. When the eventual neighbor comes by or looters wanting something neither should be able to tell. The neighbor may write you off completely as having anything useful and the looters may head straight for the home with a single light on.

 

[⚞⛇⚟]

I have been thinking about creating a large Lithium-ion power bank because 18650s/21700s/(whatever size is cheapest) are cheap and rechargeable. While I really like the idea of a Lithium-ion power bank, it seems kinda wasteful because the life of the Li-ion cells are really short.
Anyone know of alternatives to Lithium-ion or ways to repurpose them once they start to go to shit?

 

[Oxyjen]

I have been thinking about creating a large Lithium-ion power bank because 18650s/21700s/(whatever size is cheapest) are cheap and rechargeable. While I really like the idea of a Lithium-ion power bank, it seems kinda wasteful because the life of the Li-ion cells are really short.
Anyone know of alternatives to Lithium-ion or ways to repurpose them once they start to go to shit?

Use lithium iron phosphate (LFP). Lasts a very long time and contains no rare and expensive Cobalt.
Or have a look at sodium ion, those are available now and use much more plentiful materials, with less resources used to make them.

Really if you want a lot of battery for the money, look at used EV modules on eBay. They can be made to work for standby power or a small off grid system or portable power. If you’re using them lightly they pretty much last forever.

 

[⚞⛇⚟]

Use lithium iron phosphate (LFP). Lasts a very long time and contains no rare and expensive Cobalt.
Or have a look at sodium ion, those are available now and use much more plentiful materials, with less resources used to make them.

Really if you want a lot of battery for the money, look at used EV modules on eBay. They can be made to work for standby power or a small off grid system or portable power. If you’re using them lightly they pretty much last forever.

I'll check those out. thanks

 

[Alex Hogendorp]

People in Canada has been installing solar panels on the roofs of their house to combat insanely high energy bills. Our household has recently installed solar panels on our roofs, it was a bit of a hassle though but we got it to work the way it should.

 

[Alex Hogendorp]

Sorry about the double post, but people should be aware with what they are buying before buying and installing solar panels. Many solar panel companies, especially the door to door salesman have been known for doing these.

- Buy solar panels from another company.

- Jack up the price of solar panels more expensive than normal.

- Hide certain things in the contract to avoid being sued.

- Use cheaper materials which can cause the solar panels to be defective, break apart easily or in worst case scenarios catch on fire which could burn the house down.

- Incompetently install solar panels sometimes installing them facing away from the sun.

A lot of these companies make a fortune off of scamming people and putting them thousands of dollars in debt.

 

[Darkholme's Dungeon]

Modern direct fuel injection turboengines would die even faster than atmospheric carburetor engine. So you would need to butcher some vintage car, a 2002 eco-box won't do.

Yank an old diesel car engine or newer forklift engine (I think the last indirect diesel engines in forklifts were ~2017). They're still using some engines made in the 70s (indirect injections) that you can run off diesel substitutes for years.

Get good at rebuilding a mechanical injection pump though...

 

[Cirrhosis_of_Liver]

Ok, super specific question time for all you true autists.

Say I want to pump 250 GPM of water for 24 hours out of a week (I do.) I don't need to be above 30-60 PSI, and it is downhill through roughly a quarter mile of 3 inch pipe.

How big of a solar array and battery bank would I need to achieve this if I used an electric pump? I am in the arid half of Texas. How much would this cost?

 

[IdiotPlusPlus]

Say I want to pump 250 GPM of water for 24 hours out of a week (I do.) I don't need to be above 30-60 PSI, and it is downhill through roughly a quarter mile of 3 inch pipe.

A quick search says that 3 inch pipe maxes out at 130GPM so you would need to lay another one to get to at least 250GPM ?

Talking about pumping water tho, a Hydraulic Ram is cool if you have a running river or stream you are pumping from:
https://en.wikipedia.org/wiki/Hydraulic_ram

Plenty of examples on YT using standard piping, and I had a mate in Vermont make one to get water from a stream up to his garden, it's pretty cool that it uses physics to create head pressure, same how you can use a waterfall to create Air Pressure, we really need to use more methods like those that are effectively Zero power, means more power is available for fun stuff

Also a interesting watch RE: Generating power from heat sources that are used for other purposes that was mentioned earlier in the thread

 

[candlejack]

I think biotoilets are a neat idea for an off-grid cabin. The idea of easily dealing with human waste, composting it, and getting cooking fuel simultaneously is so compelling. I've spent a lot of time living off of solar power banks and using outhouses and even just sitting on a real toilet would be so nice. I don't know anyone who has actually used the system though. I also wonder how well it would work in a colder climate.

 

[Cirrhosis_of_Liver]

quick search says that 3 inch pipe maxes out at 130GPM so you would need to lay another one to get to at least 250GPM ?

That's just plain nonsense. Three inches diameter gives you about 7 cubic inches per inch, 84.8 cubic inches per foot. A gallon being 231 cubic inches, that makes it 0.367 gallons per foot. 250 gallons therefore take up 681 feet. 681 feet per minute is 7.74 miles per hour. That's not exactly hyperspeed.

Not pumping from a running stream. I'm using an earhern reservoir of very roughly 4 acre feet, refilling from wells.

 

[Jotch]

That's just plain nonsense. Three inches diameter gives you about 7 cubic inches per inch, 84.8 cubic inches per foot. A gallon being 231 cubic inches, that makes it 0.367 gallons per foot. 250 gallons therefore take up 681 feet. 681 feet per minute is 7.74 miles per hour. That's not exactly hyperspeed.

Not pumping from a running stream. I'm using an earhern reservoir of very roughly 4 acre feet, refilling from wells.

That number sounds about right, a pipe that small will have some pretty high friction if you are talking about moving at hundreds of GPMs.

 

[Cirrhosis_of_Liver]

That's the size they use for fracking. I think the increased expense of increased pipe size is important to consider. Obviously a bigger pipe will have less friction, but a 3 inch pipe can absolutely transport that volume.

The first sentence is why I'm starting from the idea of using 3 inch pipe, not that I'm set on using it if the tradeoff to bigger stuff is worth it. I don't think a sideroll irrigator is much bigger, after all.

If I'm trying to use solar power instead of an obnoxiously noisy diesel or gasoline pump, the power savings does seem to matter more.


I got an A in calculus. Boy do I wish I remembered ANY of it.

Also, sorry if my first post came off as combative.

 

[IdiotPlusPlus]

That's the size they use for fracking. I think the increased expense of increased pipe size is important to consider. Obviously a bigger pipe will have less friction, but a 3 inch pipe can absolutely transport that volume.

Not my area of expertise tbf, but looking a bit more here says that number might just be the low pressure/gravity number, so you might be able to get away with a 12v DC sump pump or something that brings it up to 20 PSI

Sorta gotta know that bit before you can work out the power side right, if you are pumping for 24hrs, you are going to need Batteries, which will have to be sized to the pump power consumption+buffer(also a theft target), which is why if you could use a no-power system it would be better, even something like using a lower GPM gravity flow to fill a surge tank closer to the end of the pipe that could store the 24hrs worth, that way in low demand periods the tank is refilling but if there are high demands periods it's covered by the tank.

Depending on your needs and where the output is from the reservoir you might already have enough hydraulic head pressure to get the pressure you need for your target GPM if it's above where it's getting used, might be worth getting a height map of the area, def worth getting the numbers before going all in on a specific type of power solution

 

[NKVD qt]

I mean, probably? I don't know shit about farming lol I was just thinking "What would be a biomass-heavy thing to grow" - you can gasify anything which has a carbon content. You can technically do it wet - you're just heating it up and insulating it to the point that it self-sustains and then limiting the oxygen intake to the minimum.

I do know that bamboo is mainly composed from atmospheric CO2 and water, so afaik it doesn't really damage the soil. Apparently it "damages" it literally, the roots are very strong and break brick - but that's not a problem.

Gasifiers are a sweet middle-ground which have a pretty wide history - they have been used, successfully, to run vehicles and made up a majority of war-time vehicles in Nazi Occupied Europe (due to the wartime petrol shortages) - advanced shit can make liquid petrol at a rate of 1:5 by mass; as in, 5kg of wood making 1kg of liquid petrol.

(yes, this is on my list of things to test)

You should look into coppicing and pollarding keeps trees alive and can even increase wood yield while making processing easier and not killing the soil.

You would still need a good source of fertilizer. Livestock and or human waste could be turned into chemically safe liquid fertilizer and even more flammable gasses using a bio digester.

 

[Scatty]

I have 7kw of solar panels and 38kwh of batteries. It's a good system but even with something that large, you still need a good wood stove in the winter.

As others have pointed out, wood gasification is the holy grail for off grid energy.

It was fridges and ACs I was thinking of in particular. Someone mentioned specifically running a generator for a fridge and window ACs in the thread.

I don't know a ton about inverter generators. My experience with inverters is with car and RV inverters. I just know a lot of inverters don't output pure sine waves which is something that could be problematic if you intend to run a fridge or a freezer off it.

Even with pure sine wave inverters you can potentially have issues (like my UPS wailing at me). I use denoisers on anything with a compressor and for my office electronics.

 

[IdiotPlusPlus]

I have 7kw of solar panels and 38kwh of batteries. It's a good system but even with something that large, you still need a good wood stove in the winter.

As others have pointed out, wood gasification is the holy grail for off grid energy.

Hmmm, If you already have the solar, I wonder if small scale hydrogen from the excess would be handy, even better if you could store it as methanol or something, if you could slowly build up more stable fuel during summer that could be used in winter to run other things.

A man can dream right xD

 

[Sperg_rancher]

Ok, super specific question time for all you true autists.

Say I want to pump 250 GPM of water for 24 hours out of a week (I do.) I don't need to be above 30-60 PSI, and it is downhill through roughly a quarter mile of 3 inch pipe.

How big of a solar array and battery bank would I need to achieve this if I used an electric pump? I am in the arid half of Texas. How much would this cost?

a 10 horsepower electric pump will be about what you want. that's about 7.5kW.
you'll need 180 kWh, but round that up to 220kWh for those times when you need more, and to increase battery lifespan.
that means you're paying ~30$ a week in electricity for this, if taking from the grid.
Lithum is 130$ per kWh, so expect about 28k$ in batteries
good panels will give you 200w/m2 in texas (even if they're rated for 230w/m2), and you only need the battery power once a week, you only need 4kW of cells, so @1$/watt, that's another 4k$.
toss in other electrical supplies (conduit, MPPTs, BMS, inverters, etc) and you'll want to add in an extra 2k$

so this is a 32k$ project for supplies, if you do it yourself.
assuming electricity increases at 5% per anum, this will pay itself off in 5 years. If you only use the batteries for 24 hours at a time, with proper cooling, you can expect the batteries to be about at the end of their usable life around this time, and the solar panels will be at 70% of their initial rating. if you increase the number of cells to 300kWh (6kW of solar needed), you'll get 2x as many charge cycles in the lifetime of those batteries.

 

[Cirrhosis_of_Liver]

Thank you!

And it would pay for itself very quickly if you consider running power out there would be like ten grand at least. The sun is more places than powerlines are.

 

[Sperg_rancher]

Thank you!

And it would pay for itself very quickly if you consider running power out there would be like ten grand at least. The sun is more places than powerlines are.

Yep! I did not include the price of the pump in there, just the electrical portion, so make sure to add those costs too in your estimates.