Looking for help planning and building a Home Renewable Cell

[CONSIDERABLE SHOUTING]

Hey dudes, I want the aid of the Endless Sphere brain trust for a personal goal of mine- building a powerwall and small renewable cell. Neat goal that was hamstrung by not having much money, except I know from personal experience that there's ways around that when it comes to skill and knowledge- and now, solar panels are becoming cheaper and cheaper by the year with old systems going up for sale when the costs of new (more efficient) panels amortize the cost.

What I'm looking for is advice, ideas, pretty much anything for me to hot rod my friggin home into some kind of techo-wizard palace for renewables, and do it cheaply. I'm not worried about total Kilowatt, because my laws have near the same price of a 1Kw cell versus a 10Kw cell and my roof is "average"- I'm more than ready to erect a stand of some kind, very willing to use trackers, basically anything to become my local neighborhood mad scientist. My ultimate goal is to have a small cell combined with some kind of low-speed windmill (because I have tons of trees, and I want to make one as cheap as possible to really know how they work) and a basic powerwall to seriously cut into my energy use and maybe give me a few hours of power in an outage. In particular, I'm looking for:

• Any build threads or examples of Savonious or Lenz-style wind turbines? I have a Fischer and Paykel motor I plan to convert
  thanks to The Back Shed and I hope to make a junkyard windmill for extra juice, but I'm not sure how to convert BLDC power into something usable, let alone super cheaply. I know they're not efficient, so any power as cheap as possible is the goal, lol

• Anyone have methods of testing your yard- not your roof- for solar positioning? I wanted to build a pergola or something similar and I might as well incorporate that into my solar goals.

• Does anyone here have a thread on a basic renewable cell?

• And outside of the DIY Powerwalls forum, does anyone know of cheaply built home backup power systems? local scrapyards near me have had lead-acid cells meant for government installations that have appeared for sale in the past, but moving thousands of pounds of lead is difficult to say the least :lol:

Any ideas at all would be greatly appreciated! I've attached an image of my home from aerial view from project sunroof, which claims I could get up to 9.3Kw total; my utility bill is closer to $45, so by their metric only a ~3.5Kw total would be needed.

 

[john61ct]

"renewable cell"

Does this have a specific meaning for you apart from deep cycling storage bank?

Powerwall is a brand, but yes DIYers use cylindricals to make a version, only "cheap" usually because the cells are past EoL.

Completely separate that goal, from the solar input side, or windmills for that matter.

DIYsolar forums and the Reddit sub are good sources for the former.

Best to take a systems approach if you really want it to be effective, save up for each component in advance.

But of course just fooling around with whatever you can scrounge can be a fulfilling hobby too.

First big question, do you want it to be off-grid, standalone

mobile usage, like for a campervan or RV or remote cabin or shack?

or integrated to feed back into the utility grid?

Do you own your home? No plans to move in coming decades?

 

[CONSIDERABLE SHOUTING]

"renewable cell"
Does this have a specific meaning for you apart from deep cycling storage bank?

Just my phrasing for the entire "unit", panels + Windmill.

Best to take a systems approach if you really want it to be effective, save up for each component in advance.

But of course just fooling around with whatever you can scrounge can be a fulfilling hobby too.

Yep! Agreed.

First big question, do you want it to be off-grid, standalone mobile usage, like for a campervan or RV or remote cabin or shack? or integrated to feed back into the utility grid? Do you own your home? No plans to move in coming decades?
[/quote]
Integrated to feed back into the grid. I own my own home, but I don't know how long I'll be staying there.

 

[nicobie]

Be sure to take a long look at the grid tie agreement you'll have to sign. At times it can be quite onerous or short term. Mine will be running out in a few years. When it does I'll be going completely off grid as my $/kWh will go sky high for when I do need the grid power. Looks like I will be needing more panels and a nice big battery for when the sun doesn't shine.

 

[JackFlorey]

Anyone have methods of testing your yard- not your roof- for solar positioning? I wanted to build a pergola or something similar and I might as well incorporate that into my solar goals.

If you're in the northern hemisphere, point em south and you're good. If you want to get fancier you can use a Solar Explorer or the like to get a map of what trees will block you. But just by looking you can get a pretty good sense of whether trees to the south will block you.

If you have morning clouds point them a little bit west of south. If you have evening clouds do the opposite. If you have high air conditioning loads, point em west of south.

For elevation, use latitude+15 if you are doing grid offset only (zero export) or latitude-15 if you are doing full grid tie or battery storage. But realistically you go with whatever slope the roof is. It doesn't have to be exact.

Does anyone here have a thread on a basic renewable cell?

Like a battery? Used forklift batteries are generally cheapest per kwhr. If you are going new, Costco T105 lead acids are cheapest. If you are good electrically, conversion of a used 400V EV battery will get you a LOT of bang for the buck - but takes a lot of work to get working well.

And outside of the DIY Powerwalls forum, does anyone know of cheaply built home backup power systems?

Well first decide what you want to do.

Home backup system - easy, not much reduction of load, relatively cheap
Zero export - easy, even cheaper, works very well if you juggle your loads to use more power during the day
Grid tie - not hard but you do need a permit and sign-off from the AHJ which is annoying.
Hybrid - the holy grail but it's expensive and you still need the sign off.

Most people who word their requests like you do are going to go with backup or zero-export since they don't need sign-offs.

There are slightly different approaches for all of them, so let us know which one sounds the best.

 

[CONSIDERABLE SHOUTING]

If you're in the northern hemisphere, point em south and you're good. If you want to get fancier you can use a Solar Explorer or the like to get a map of what trees will block you. But just by looking you can get a pretty good sense of whether trees to the south will block you.

Sadly everything blocks me :lol: Which is why I'm looking to making it move with the sun as well. But good to hear I'm likely overthinking it.

Like a battery? Used forklift batteries are generally cheapest per kwhr. If you are going new, Costco T105 lead acids are cheapest. If you are good electrically, conversion of a used 400V EV battery will get you a LOT of bang for the buck - but takes a lot of work to get working well.

Yeah! My only 'adversion' to lead acids is the logistics to move them. If I could, Battery clearing house has a Sonnen LiFePO4 powerwall cell I'd buy in a heartbeat but they only allow in-person pickup. Otherwise? I'll use what's cheapest, and I've seen local Nissan Leaf packs at 50% degradation for $1,000 locally before; that's still ~12 Kw!

Home backup system - easy, not much reduction of load, relatively cheap
Zero export - easy, even cheaper, works very well if you juggle your loads to use more power during the day
Grid tie - not hard but you do need a permit and sign-off from the AHJ which is annoying.
Hybrid - the holy grail but it's expensive and you still need the sign off.

Hybrid would be the goal; but with my money that's likely not possible. I take it home backup is just, having a battery chilling in the basement ready for me to jack into when weather gets bad? Or is that Zero export? I could do that, if I ran something like say, my heat pump off of it near exclusively. Frankly, I'll...

Most people who word their requests like you do are going to go with backup or zero-export since they don't need sign-offs.

... need a clearer definition :lol: Thank you tho!

Be sure to take a long look at the grid tie agreement you'll have to sign. At times it can be quite onerous or short term.

Good to know, thanks.

 

[JackFlorey]

Yeah! My only 'adversion' to lead acids is the logistics to move them. If I could, Battery clearing house has a Sonnen LiFePO4 powerwall cell I'd buy in a heartbeat but they only allow in-person pickup. Otherwise? I'll use what's cheapest, and I've seen local Nissan Leaf packs at 50% degradation for $1,000 locally before; that's still ~12 Kw!

Leaf packs are great. Gen 1's are easy to disassemble and reassemble in whatever voltage you want. Gen 2's - not so easy (pouch cells.) But still doable.

If you can work with 400 volts you can leave them as-is. But again you'd have to be very good with electronics to make that work.

Hybrid would be the goal; but with my money that's likely not possible. I take it home backup is just, having a battery chilling in the basement ready for me to jack into when weather gets bad?

Yes. You can also run some local loads off it. (fridge for example)

Or is that Zero export?

Zero export is, at simplest, a grid tie inverter that will never output more than you are using. You can get a 2000 watt Chinese one for about $400.

At its most complex, it's a full hybrid inverter like the Sol-Ark. But they are big bucks.

No signoff needed for either.

 

[Hillhater]

. I've attached an image of my home from aerial view from project sunroof, which claims I could get up to 9.3Kw total; my utility bill is closer to $45, so by their metric only a ~3.5Kw total would be needed.

.??… are you saying your electricity usage is just $45 month ?
What is that in kWh ?…a daily usage figure would be helpful.
That 9.3kW figure is just how much solar they can fit on your roof,.. it tells you nothing about how much energy it will produce.
For that much more detail is needed, ..location, local sun days, tree shading ( especially winter), etc.
But, with the trees seen in the aerial photo, any panels would likely be best mounted as high as possible on the roof ( single or double story ?)

 

[gobi]

ROI will be on the negative side,

I use around 1000 kw of power a month on average (how that is a mystery), even for me ROI is negative.

If my grid allowed me to sell back power and I could avoid batteries to store the power, then it could be feasible. But there is NO quota remaining to sell back power.

Look into simple technology to harness solar like preheating water using a heat exchanger system that is cheap.

 

[CONSIDERABLE SHOUTING]

What is that in kWh ?…a daily usage figure would be helpful.
That 9.3kW figure is just how much solar they can fit on your roof,.. it tells you nothing about how much energy it will produce.
For that much more detail is needed, ..location, local sun days, tree shading ( especially winter), etc.
But, with the trees seen in the aerial photo, any panels would likely be best mounted as high as possible on the roof ( single or double story ?)

I'll have to do a full energy audit, but first I'll have to learn how to do that :lol:. Tree shading will be hard due to the hillside the home faces, in winter the sun quickly is blocked by the treeline. I'd rather not give my exact location because internet people are weird. I have to find some kind of test, like a simple sensor I can install in some kind of grid, that'll say how much sun I get and where I get the most of it. That reason is why I consider an array in the backyard on a rotating stand.
Home is a 2-story, but it's set into the hillside so it's more 1 & 1/2.

ROI will be on the negative side,

I use around 1000 kw of power a month on average (how that is a mystery), even for me ROI is negative.

If my grid allowed me to sell back power and I could avoid batteries to store the power, then it could be feasible. But there is NO quota remaining to sell back power.

Look into simple technology to harness solar like preheating water using a heat exchanger system that is cheap.

I have yet to see if that's the case, but that's more due to the sheer number of variables; I have pretty good rebates and I'm only looking at B-grade or used panels.
I COULD try some kind of water system, since I have a heat pump and my water tank is nearly 20 years old; but that's another massive cost.

 

[nicobie]

While it's not necessary, I found that installing a 'Sense' wifi shunt in my electrical panel (https://sense.com/) helped me figure out my needs.

It's super easy to install and kind of fun checking out the graphs it generates.

 

[gobi]

Op,

I looked into ground solar array to keep the cost low, cool b-grade panels sound good.
There is an outfit around Phoenix AZ that has great deals,

Preheating water using solar:

you can add inline to your existing system, you will not have to change anything.

Solar water coils > antifreeze fluid flows to stand alone heat exchanger > preheated fresh water runs to water hear

The 2 system never mix, the main cost is the heat exchanger. I have seen guys make a plexiglass shallow greenhouse to house the heating pipes.
If I ever have a swimming pool, definitely look into heating water this way

 

[Hillhater]

………
The 2 system never mix, the main cost is the heat exchanger. I have seen guys make a plexiglass shallow greenhouse to house the heating pipes.
If I ever have a swimming pool, definitely look into heating water this way

?..why bother with the heat exchanger for a swimming pool ?
Conventional solar pool heating just runs the pool water through a “mat” of solar tubing, and back to the pool.
You may not even need a additional pump , just redirect the filter pump through the solar circuit.
Mine runs that way and the return water is 30C hotter than the pool water.

 

[gobi]

………
The 2 system never mix, the main cost is the heat exchanger. I have seen guys make a plexiglass shallow greenhouse to house the heating pipes.
If I ever have a swimming pool, definitely look into heating water this way

?..why bother with the heat exchanger for a swimming pool ?
Conventional solar pool heating just runs the pool water through a “mat” of solar tubing, and back to the pool.
You may not even need a additional pump , just redirect the filter pump through the solar circuit.
Mine runs that way and the return water is 30C hotter than the pool water.

Good point, yes, meant the solar heating for pool,
30c hotter nice, some day!

 

[CONSIDERABLE SHOUTING]

While it's not necessary, I found that installing a 'Sense' wifi shunt in my electrical panel (https://sense.com/) helped me figure out my needs.

It's super easy to install and kind of fun checking out the graphs it generates.

Interesting! I'll look into it.

I looked into ground solar array to keep the cost low, cool b-grade panels sound good.
There is an outfit around Phoenix AZ that has great deals,

Preheating water using solar:

you can add inline to your existing system, you will not have to change anything.

Solar water coils > antifreeze fluid flows to stand alone heat exchanger > preheated fresh water runs to water hear

Swimming pools would be neat, but if I did one I'd try to make it as natural as possible for some kind of permaculture system.
As for panels, Govdeals has a university in Colorado that's getting rid of theirs that I'm keeping an eye on. I think I could use one of our families spare vehicles and load them by hand; if the price stays this good (which it wont LOL) it'll be worth the ~16 hour drive.
https://www.govdeals.com/index.cfm?fa=Main.Item&itemid=4986&acctid=3337
There's also inverters in Georgia that fit the limits my power utility sets, but I have no idea if they are even willing to ship. Most sellers aren't.

 

[gobi]

good luck on the CO deal, 16 hour drive ouch, do the math if the gas is worth it.

https://santansolar.com/

I call them satanic solar, lol, foot hills of santan mountains. They have great deals, no connection with them

 

[CONSIDERABLE SHOUTING]

good luck on the CO deal, 16 hour drive ouch, do the math if the gas it worth it.

https://santansolar.com/

Thanks! I'm not holding my breath on it, mostly because such a drive would SUCK lmao