diy solar

diy solar

Need help and a little direction

J

johnskdyvn

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Joined
Nov 8, 2021
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Hello all, i'm new to this site although i've been watching Will's videos for about a year now. I'm a total newbie when it comes to solar. I just moved to an off grid cabin. Right now, I'm trying to piece together a system for my 400 sq foot cabin. I'm attempting to buy as much of the hardware needed as the supply chain is starting to crash and burn.
So far, I have bought a Growatt 3K all-in-one , and (4) SOK 12v 206ah batteries. I am currently trying to find a generator to top off the batteries on a low-light day. I have NOT bought solar panels yet.
I was planning on connecting the 4 SOK batteries in series to make it a 48v system. I am currently looking at the following generator to top off the batteries when needed. Is this enough generator to do the job?

https://www.homedepot.com/p/Westing...emote-Start-and-RV-Ready-iGen4500DF/314515883

I don't plan on running much at the cabin. A refrigerator, a chest freezer (10 cu foot), 2 lights, and some outlets to power my laptop and recharge my phone. If i need to use the microwave, I was just planning on running the generator for the time needed.

Any and ALL advice would gladly be accepted. Am I missing something (besides the solar panels)? I figured if I can get everything I need together, I can then plan on asking for help to make sure it is all wired correctly. Electricity is the ONE thing I do not feel comfortable working with with the exception of replacing outlets, etc. Would i need fuses for this system? Circuit breakers? I already have the cabin wired for the generator. It is one 12g wire that powers the 2 lights and the outlets in the cabin.

Thank you so much for any and all help.
Johnny
 
Solar panels are the first thing I would have bought. I would not delay that any more. Get the panels before you get the generator. BTW, I saw a 5000W Champian on the HomeDepot site for 650$. I think the unit you selected is very over-priced. Do you need dual-fuel capability? Does your Growatt model take 120V or 240VAC as it's input?

Your loads sound about what I'm running at my own place right now. Where are you physically located at? Do you know what your winter sunhours are? I'd guestimate you'll need at least 1500W of panels to get by in winter at a 3kWh rate per day. Shop locally for your panels instead of ordering online. Shipping is the killer for panels. You'll get far better deals with cash and carry locally then you will on the internet. Some of my highest quality, best performing panels I've bought to date were used panels I bought off Craigslist.

If you bought say six 250W grid-tie panels, you could wire them in a 3S2P configuration, 16A at ~90VDC. Is your's the model with the 145Voc limit? You could incrementally add additional 3 panel strings if you don't find you're making enough power.
 
MichaelK said:
Solar panels are the first thing I would have bought. I would not delay that any more. Get the panels before you get the generator. BTW, I saw a 5000W Champian on the HomeDepot site for 650$. I think the unit you selected is very over-priced. Do you need dual-fuel capability? Does your Growatt model take 120V or 240VAC as it's input?

Your loads sound about what I'm running at my own place right now. Where are you physically located at? Do you know what your winter sunhours are? I'd guestimate you'll need at least 1500W of panels to get by in winter at a 3kWh rate per day. Shop locally for your panels instead of ordering online. Shipping is the killer for panels. You'll get far better deals with cash and carry locally then you will on the internet. Some of my highest quality, best performing panels I've bought to date were used panels I bought off Craigslist.

If you bought say six 250W grid-tie panels, you could wire them in a 3S2P configuration, 16A at ~90VDC. Is your's the model with the 145Voc limit? You could incrementally add additional 3 panel strings if you don't find you're making enough power.
Click to expand...
Thank you for your reply. I bought the 3kw model that is 120v. The place I'm at is near Harriet, Arkansas. I am actively shopping for panels on CL and FB marketplace. I was thinking about 3kw of panels. I was hoping the battery capacity would be good for what little I'm running. i did forget one thing...i was also planning on running an 8000 BTU AC for 3 months of the year as I heard the heat here is brutal.
My model does have the 145Vdc limit.
As for the dual fuel generator....i was wanting one that could specifically run off of both gasoline and propane. Propane because it's easier to keep. I would probably use gasoline until the price got to be too astronomical to use. I am having 500# of propane brought up in 5x100lb tanks. This is the largest tank i can safely get to where I am. No refueling truck can make it to where I am.
 
johnskdyvn said:
Thank you for your reply. I bought the 3kw model that is 120v. The place I'm at is near Harriet, Arkansas. I am actively shopping for panels on CL and FB marketplace. I was thinking about 3kw of panels. I was hoping the battery capacity would be good for what little I'm running. i did forget one thing...i was also planning on running an 8000 BTU AC for 3 months of the year as I heard the heat here is brutal.
My model does have the 145Vdc limit.
As for the dual fuel generator....i was wanting one that could specifically run off of both gasoline and propane. Propane because it's easier to keep. I would probably use gasoline until the price got to be too astronomical to use. I am having 500# of propane brought up in 5x100lb tanks. This is the largest tank i can safely get to where I am. No refueling truck can make it to where I am.
Click to expand...
The thing about propane is that it can just sit there and it lasts forever. Gasoline is likely to go bad after two years or so. I'd agree that dual-fuel is a good choice. But, that model you showed is still pricy, even for a dual-fuel. Home Depot has some more economical choices.

Yes, personally I'd go with more panels. 3000 is a good number. Here's something you might be interested in. I designed and built these rotating single-pole panel arrays out of unistruts and schedule 40 steel pipe. Although I mounted four panels in portrait here, you could do six panels in the landscape orientation. Two of those arrays carrying six 250W panels each would equal your 3000W. Since they rotate, I can pretty much guarranty you'd be able to make 15+kWh per day of power, even in winter. So, you'd have two arrays wired in a 3S2P configuration, delivering about 32A at 90V to your growatt.

Position the arrays so you can rotate East to get morning sun, and West to get afternoon sun, and you could run your air-con without any battery drain till about sunset. The array you see in the pics below is facing due West, so I can keep the air-con running till about 6pm at my location. Past 6pm, and this array starts getting shaded by Oak trees like what you can see in the pics.
 

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Yeah lets keep this between us BUT this is the one that we use the hell out of in the oil fields ... https://www.amazon.com/gp/product/B07Q1DLKBG/ref=ox_sc_saved_image_7?smid=ATVPDKIKX0DER&psc=1 ... then again we charge our batteries with a 50A charger and do lots of other things with the generator -- BUT its a workhorse .. its inexpensive .. runs on propane and petrol ... total price delivered is about $970 ...

Now if you don't need anything that large (I like large becuase I can charge the hell out of the batteries quickly and then shut down the generator) ...

But if you want something smaller https://wenproducts.com/products/4000-watt-open-frame-inverter-generator which is about $400 .. good little generator ... not quiet .. but good ...
 
Last edited:
MichaelK said:
The thing about propane is that it can just sit there and it lasts forever. Gasoline is likely to go bad after two years or so. I'd agree that dual-fuel is a good choice. But, that model you showed is still pricy, even for a dual-fuel. Home Depot has some more economical choices.

Yes, personally I'd go with more panels. 3000 is a good number. Here's something you might be interested in. I designed and built these rotating single-pole panel arrays out of unistruts and schedule 40 steel pipe. Although I mounted four panels in portrait here, you could do six panels in the landscape orientation. Two of those arrays carrying six 250W panels each would equal your 3000W. Since they rotate, I can pretty much guarranty you'd be able to make 15+kWh per day of power, even in winter. So, you'd have two arrays wired in a 3S2P configuration, delivering about 32A at 90V to your growatt.

Position the arrays so you can rotate East to get morning sun, and West to get afternoon sun, and you could run your air-con without any battery drain till about sunset. The array you see in the pics below is facing due West, so I can keep the air-con running till about 6pm at my location. Past 6pm, and this array starts getting shaded by Oak trees like what you can see in the pics.
Click to expand...

So fuel with ETHANOL in it starts breaking down significantly after 6 months ... Putting STA-BIL in it helps allot BUT using NON-ETANOL- fuel is where its at .. in Texas its pretty easy to find ... Most QT Fuel stations have it ... well worth the extra pennies ... out here in the oil patch we fricking hate the Ethanol stuff -- just tears the hell out of our stuff that sits for a while that's only used periodically ...

I think honestly I would only use 2 year old ETHANOL fuel to start fires .... :)
 
I don’t have any problem with old fuel .
I do try to use it every year and all so keep every thing full or empty but not in between .
fuel additive works good
 
I made my roof pitch at 42o and put the panels up .
I get ok power in the winter and plenty of power in the summer .
I think you can just add a few extra panels and be a head of the game .
 
Thank all of you for your helpful information so far. I do need to buy cable to hook the batteries up in series. With the batteries being 12v 206ah, should i just go with 4 gauge cables? Also, in Will's video of the 3k Growatt setup, he doesn't mention the need for fuses in the cables. Is this correct, or should i be buying fuses to put in between the batteries and the Growatt? Sorry for all the questions. I just want to make sure i get it right. There is no fire department out here to put out a fire. :0
 
Also, will the wattage of the generator increase the speed of topping off the batteries? Should i go with a bigger generator? I have read alot about how the generator should be an inverter type generator. That is the reason i was looking at the generator i posted earlier.
Thanks !
 
I’ve been looking at that model as well. Been living in my RV for the last few months and installing a 400sf tiny home off grid. I’ve been using a generator a lot! I have several to choose from in my collection. the two I use the most is a Champion 3100 gas with remote start. The remote start is fabulous. I keep it hooked to my 100amp charger and if I need more power in the middle of the night or something just hit the button and it’s running. Uses a bunch of fuel though and with it being $4 a gallon propane option would be nice. I bought a 700w Baja propane generator that powers a 30 amp charger. I can run it for a week off one 20lb propane tank. In fact it’s running right now and has been running for the last hour. I run it until my charger says 14.2 or I go to bed. My RV furnace just eats though the power! And it’s been in the low 20’s. Everting I run off my inverter only draws about 100w unless my son’s playing video games then it’s about 250w. I have his 250sf cabin wired and plugged into the side of my RV.

I Started ordering stuff for the tiny house also because of the supply chain issues. My batteries are floating at sea right now. I chose signature Solar’s 600ah 48v battery rack system. To go with that a Magnum MS-4448-pae 240 split phase since the tiny house is already wired like that. 10 REC365w panels that are also floating at sea and a Victron 250/70 charge controller. I plan to run a 240v 9000 btu mini split system next year With this system.
 
johnskdyvn said:
Also, will the wattage of the generator increase the speed of topping off the batteries? Should i go with a bigger generator? I have read alot about how the generator should be an inverter type generator. That is the reason i was looking at the generator i posted earlier.
Thanks !
Click to expand...
You really don't want the generator to "top off" your batteries. That's really a waste of fuel. You'll get the best performance if you start the generator in the very early morning, and bulk charge past 80%. Then shut the generator down and let whatever solar resource you have finish the topping off.

What your inverter might do is want to "qualify" the power coming in from the generator. That means the inverter looks at the voltage and Hz stability and decides whether or not the generator is "qualified" to supply power to it. In real-world practice, I've found that as you inch the charging rate up, it becomes harder and harder to get the generator "qualified". That is, the inverter will accept the power at a lower charging level, but reject it if the generator is getting too labored.

I'd recommend going with a generator at least twice the capacity you want to charge at, so the generator is not being pushed so hard that quality drops. You should go into your inverter's menu and find where the charging setting are and play with them.

Inverter generators are supposed to have a cleaner sine-wave, so that most likely will help with the qualification process.
 
johnskdyvn said:
Also, will the wattage of the generator increase the speed of topping off the batteries? Should i go with a bigger generator? I have read alot about how the generator should be an inverter type generator. That is the reason i was looking at the generator i posted earlier.
Thanks !
Click to expand...
With a little generator like that you will need to turn down the built in charger two about 50%. That what my neighbor has to do with his Magnum MS-4024. If he uses a 9k he can turn it up to 80% off one of the 120v outlets.
 
MichaelK said:
You really don't want the generator to "top off" your batteries. That's really a waste of fuel. You'll get the best performance if you start the generator in the very early morning, and bulk charge past 80%. Then shut the generator down and let whatever solar resource you have finish the topping off.

What your inverter might do is want to "qualify" the power coming in from the generator. That means the inverter looks at the voltage and Hz stability and decides whether or not the generator is "qualified" to supply power to it. In real-world practice, I've found that as you inch the charging rate up, it becomes harder and harder to get the generator "qualified". That is, the inverter will accept the power at a lower charging level, but reject it if the generator is getting too labored.

I'd recommend going with a generator at least twice the capacity you want to charge at, so the generator is not being pushed so hard that quality drops. You should go into your inverter's menu and find where the charging setting are and play with them.

Inverter generators are supposed to have a cleaner sine-wave, so that most likely will help with the qualification process.
Click to expand...
This is pretty much what I believe is the owner of signature solar explains in one of his YouTube videos. He recommended a separate charger hooked to a smaller generator like what I am doing in my RV.
ill see if I can find the video and link it.
 
It sounds like you are getting some good advice. I have a 2 kw solar with growatt 24 volt on Lipo4 in a RV. Also Schneider xw6848 and 6.1 kw solar. I am near Hector Arkansas about 40 miles south of you if you need anything let me know.
 
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