Mudflap's Solar Adventure

[mudflap]

Seems like I could dig through and find answers, but maybe someone else can benefit from my dumb questions....

The world is crazy.

I'm reading about folks in Asheville NC who wish they had a lot of things right now after Hurricane Helene, but one thing they are wishing for echoes what prompted my "log home journey" in the first place: they want ice.

Which is a weird place to start for a log home journey, I know....

Back in April 2011, there was a supercell tornado outbreak here in the South - over 300 tornadoes tracked across the region in one day. I made some mistakes that day like, "let's go home and ride this one out - I'll go fill up the cars with gas in the morning." The power went out around 3 in the afternoon, and didn't come back on for about a week. School was cancelled, my job was cancelled. There was no news (similar to what I've heard from Asheville). There were opportunist burglaries (you cannot imagine how dark a city can be at night with no streetlights). Luckily, we had an ornery dog and fence that encircled the yard and our cars at night. Like everyone else, after about 3 days, we had cooked all the stuff in our freezer. We avoided gas lines (and fights). We avoided getting burglarized or murdered, too. But we mostly missed ice and refrigeration. That storm is what prompted us to make a plan to get out of the city. I finally took the LHBA class in 2014, bought some land outside the city, and you know the rest of the story.

A couple years ago, I was gifted some solar panels (24 actually): They are 200W / 7A / 28v evergreen solar panels a guy gave me for the price of shipping them here from Texas ($300). They are brand new, but have "slight defects" in the manufacturing process - I guess that means they are slightly less efficient than brand new ones.

I wanted to get the garage built with a roof at the correct angle for our area (I found out that is 29 degrees), but like I said, the world is crazy, so I think I should get going on at least part of this project and get my fridge hooked up to solar. I think I can just move the wiring off my main panel and onto a sub "solar panel somewhere still inside the house.

I planned my breaker box so I can put a transfer switch underneath it if I ever go "full solar". I assume I could legally switch the whole house over to solar if I want to - probably some laws I have to follow, but only in a "not grid down situation". But that's not my current project.

I just want to get the fridge hooked up.

It looks like I need 3 panels (so I'll do 4). I think a 24v system makes sense since my panels are rated for 28v. I'm guessing I should connect them in parallel to keep the voltage the same going into my charge controller. I assume I can use a PWM controller since I don't really care about efficiency at this point.

I'm still researching the charge controller and inverter, so chime in if you can point me in the right direction here.

For batteries... I guess I should keep it simple and do either sealed Lead Acid batteries, but should I do 2 @ 12v or 1 @ 24v? pros and cons? Or Lithium? And actually, I found the (what I'm going to call) Skip's Butt and Pass Battery: an Edison / NiFe battery. Edison invented these batteries back in 1901. The reason I'm calling them LHBA batteries is because they are stupid simple, you can make them out of off the shelf parts, they don't use any exotic materials (just steel / nickel / some kind of wafer insulator / and drano (potassium hydroxide). a cell of plates gives off 1.2 v (or microvolts?), so if you stack 10 plates together - that's 12v. They offgas hydrogen, but that's about the most dangerous thing about them - they are apparently unbreakable (you can't overdischarge them?), and renewable, and will last darn near forever - which is why nobody makes or sells them here in the USA. See why they are the LHBA of batteries? DIY. yeah. Anyway, I think I should start with "the usual" and test out the edison batteries on the side. Then if I get confident enough, swap them in in a few years...

Ok, I guess I need to get going with this project - should I mount it on the porch roof which is South-facing, and run wires to a little battery hut somewhere? Any good resources? I've already looked all over the internet - there's a ton of info, but haven't bumped into anything "comprehensive" -what do you got? books? websites?

[donjuedo]

I wanted to get the garage built with a roof at the correct angle for our area (I found out that is 29 degrees)

"correct angle" is subject to interpretation. Typically, that would be the location's geographic latitude. But when seasons change, so does sun angle, so latitude is a convenient compromise between summer and winter. Is that good? Yes. Is that best? No, not really. In this context of solar energy, it does not take into account that summer delivers more sunshine. My preference is to aim directly at the sun during winter, and when summer comes, the angle is less efficient, but the sun is delivering more energy. At some point, though, it's just splitting hairs.

I just want to get the fridge hooked up.

It looks like I need 3 panels (so I'll do 4). I think a 24v system makes sense since my panels are rated for 28v. I'm guessing I should connect them in parallel to keep the voltage the same going into my charge controller. I assume I can use a PWM controller since I don't really care about efficiency at this point.

24 VDC is fine. Here are other factors to consider:
12 VDC components are the most common and readily available so you get the most options to choose from.
A fridge and freezer are not big power hogs, so spec'ing the system to 24 VDC or even 48 VDC won't provide the most common benefit people look for -- lower resistive loss, because of lower DC current in a higher voltage system. The difference is technically still true, but the amount is not significant for the fridge and freezer.
Since this is a temporary arrangement, which components do you want left over after it's torn down?

I'm still researching the charge controller and inverter, so chime in if you can point me in the right direction here.

I'd recommend excluding all but "pure sine wave" inverters, Modified sine wave and other designs are cheaper and simpler to design, but the output waveform only crudely resembles the sine wave supplied by the power grid. In effect, the output is a sine wave PLUS a whole lotta noise making it not a sine wave any more. Many things don't care, but some things do, and when I build something, I don't want to have to keep precautions in the back of my mind for how not to ruin something later.

For batteries... I guess I should keep it simple and do either sealed Lead Acid batteries, but should I do 2 @ 12v or 1 @ 24v? pros and cons? Or Lithium? And actually, I found the (what I'm going to call) Skip's Butt and Pass Battery: an Edison / NiFe battery. Edison invented these batteries back in 1901. The reason I'm calling them LHBA batteries is because they are stupid simple, you can make them out of off the shelf parts, they don't use any exotic materials (just steel / nickel / some kind of wafer insulator / and drano (potassium hydroxide). a cell of plates gives off 1.2 v (or microvolts?), so if you stack 10 plates together - that's 12v. They offgas hydrogen, but that's about the most dangerous thing about them - they are apparently unbreakable (you can't overdischarge them?), and renewable, and will last darn near forever - which is why nobody makes or sells them here in the USA. See why they are the LHBA of batteries? DIY. yeah. Anyway, I think I should start with "the usual" and test out the edison batteries on the side. Then if I get confident enough, swap them in in a few years...

I was most impressed by a video of Jay Leno motoring around his neighborhood in his 1908 Baker Electric car, powered by the ORIGINAL NiFe batteries (over 100 years old at the time of the video). For lead acid batteries, I've never heard rumors, folklore, or legends of such durability.

I love NiFe and bought 24 KWH ($8,000 batteries + $1,000 shipping) from CiYi battery in China. These are well made and I'm glad I got them, even though they're not yet installed.

NiFe can be reconditioned as capacity fades, so their lifespan is indefinite. I care less about upfront cost and more about cost per year. Cheap batteries are not cheap if they have to be replaced regularly.

Conditioning/reconditioning is important, so here's documentation on how to do exactly that:
http://www.autocutresearch.com/nife/

Still, car batteries are everywhere. A YouTube channel, "Sweet Project Cars", has a video on how to rejuvenate car batteries. I haven't done it, yet, but plan to. I've collected 4 car batteries for free, since they were considered dead. I'll try out the rejuvenation technique from the video and if any succeed, I'll keep doing that until I have 4 restored (free) batteries, then proceed with the project they're for.

Ok, I guess I need to get going with this project - should I mount it on the porch roof which is South-facing, and run wires to a little battery hut somewhere? Any good resources? I've already looked all over the internet - there's a ton of info, but haven't bumped into anything "comprehensive" -what do you got? books? websites?

A great resource for learning about practical solar is Will Prowse, a YouTuber. His earlier videos are very hands on, but they're all useful and done well.

[mudflap]

"correct angle" is subject to interpretation. Typically, that would be the location's geographic latitude. But when seasons change, so does sun angle, so latitude is a convenient compromise between summer and winter. Is that good? Yes. Is that best? No, not really. In this context of solar energy, it does not take into account that summer delivers more sunshine. My preference is to aim directly at the sun during winter, and when summer comes, the angle is less efficient, but the sun is delivering more energy. At some point, though, it's just splitting hairs.




24 VDC is fine. Here are other factors to consider:
12 VDC components are the most common and readily available so you get the most options to choose from.
A fridge and freezer are not big power hogs, so spec'ing the system to 24 VDC or even 48 VDC won't provide the most common benefit people look for -- lower resistive loss, because of lower DC current in a higher voltage system. The difference is technically still true, but the amount is not significant for the fridge and freezer.
Since this is a temporary arrangement, which components do you want left over after it's torn down?



I'd recommend excluding all but "pure sine wave" inverters, Modified sine wave and other designs are cheaper and simpler to design, but the output waveform only crudely resembles the sine wave supplied by the power grid. In effect, the output is a sine wave PLUS a whole lotta noise making it not a sine wave any more. Many things don't care, but some things do, and when I build something, I don't want to have to keep precautions in the back of my mind for how not to ruin something later.



I was most impressed by a video of Jay Leno motoring around his neighborhood in his 1908 Baker Electric car, powered by the ORIGINAL NiFe batteries (over 100 years old at the time of the video). For lead acid batteries, I've never heard rumors, folklore, or legends of such durability.

I love NiFe and bought 24 KWH ($8,000 batteries + $1,000 shipping) from CiYi battery in China. These are well made and I'm glad I got them, even though they're not yet installed.

NiFe can be reconditioned as capacity fades, so their lifespan is indefinite. I care less about upfront cost and more about cost per year. Cheap batteries are not cheap if they have to be replaced regularly.

Conditioning/reconditioning is important, so here's documentation on how to do exactly that:
http://www.autocutresearch.com/nife/

Still, car batteries are everywhere. A YouTube channel, "Sweet Project Cars", has a video on how to rejuvenate car batteries. I haven't done it, yet, but plan to. I've collected 4 car batteries for free, since they were considered dead. I'll try out the rejuvenation technique from the video and if any succeed, I'll keep doing that until I have 4 restored (free) batteries, then proceed with the project they're for.



A great resource for learning about practical solar is Will Prowse, a YouTuber. His earlier videos are very hands on, but they're all useful and done well.

perfect! exactly what I was looking for!
Thanks!

on the "perfect angle" - I was just posting what some "enter your zip code" website told me - but it also had seasonal angles and monthly angles. I think I agree -probably best to maximize the angle in the winter since that's when you get the least sunlight. or somewhere closer to it anyway.