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diy solar

diy solar

You're going to laugh...

kris1

New Member
Joined
Sep 21, 2024
Messages
6
Location
Mo currently moving to Oklahoma
So to cut it short I'm going going to be moving off grid. It's a 8'x16' fully lofted prebuilt. I want to do full solar.

Things I need to power:
Double split ac/heater
Refrigerator
2 outlets
1 instant water heater
1 light

Things I've purchased:
3-100w monocystaline solar panels
1000w power inverter
12v 1280wh type(I can't remember hot so spell it it's odd )
Controller

All from temu

Now hear me out about that in a few.


I have 1-not a great idea of how I'm calculating this or how much power the mini split (that's the name) uses because I don't have it yet. Or how much poser i need for what else.
I have no idea how many panels or watts I need or how long is to long to have backed up. I would like no less than 3 days..
This power inverter how does that exactly work?
Can i do a system for just the power and then a separate one for everything else?

There's more questions but I'm sure some will be answered anyway. I'm trying to let myself get settled but I'm having a terrible time navigating it all or finding just the mathematics for starters.

Now the temp thing...
I've got some good stuff on there for well below price point. I'm not saying it'll be good or bad but either we'll get a good laugh or a good cry when we find out.

If it does have a Chance of going good then I'm going to need some help in finding the math and the best usage of energy or for the life of me I can't picture the ways to wire and the differences so it's not making any sense which way to do it. Or how do I wire the inverter to the breaker box? Still haven't found that one yet. Like diagrams, mathematics and charts that are simple

Thanks y'all.
 
That should power the porch light. Now on to getting everything listed powered ...
Should be a link to an energy usage spreadsheet somewhere in there
 
Well you presently just jumped out of a plane without a chute but maybe we can help break your fall
You need to get the specs on the a/c heater unit and the refrigerator as far as hot water you would be better off getting a propane unit

You are going to need more panels thinking in the 1500 to 2000 watts to run a mini split and refrigerator while charging your batteries yes batteries more than one like 4 100Ah minimum assuming you have enough sun to recharge every day

Inverter wise you are going to need a lot larger to start any type of motor look for inverter drive motors easer to run
 
Blurb time!

Well, I'll start the default answer to these questions and we can work from there. Here's you To-Do list:

1: Power audit! This will give you some important information on how big your inverter needs to be as well as how much battery capacity you'll need. There is a link in the FAQ section (I think, or someone here will post it shortly) so fill in the blanks and see what it comes up with. You'll probably need some sort of Kill-A-Watt to get accurate measurements. Are you going to be running a 12v system? 24v system? 48v system? What are the specs on your solar panels? VoC? Vmp? Being as this is a new build, throw together a wish list of what you want and estimate on the high side.

1a: Where do you live? Speccing out a system for Scotland is a LOT different numbers than Arizona due to the amount of light you actually get. Someone here can post the link to the PVwatts.com or JCR Solar Uber-Sun-Hours calculator sites to help figure out how much you'll have to work with. That will be a box in the Power Audit form.

2: Parts list: You don't need a make & model list, just a parts list to start from for reference. You'll need an inverter, a MPPT charge controller, fuses, shunt, buck converter, batteries, wire, etc. Once you have a basic list it can be fine tuned to make & models after that. If you're looking at the All-In-Ones check for correct voltage outputs (120v or 240v Split Phase for North America, 220v Single Phase for European type areas) and make sure it has enough capacity for a little bit of growth and fudge factor.

3: Budget!: Steak is great but doesn't mean anything if your wallet says hamburger. :) Figure out what you're able to spend now vs what you'll have to cheap out on now and upgrade later.

4: Tape measure! Figure out where you're going to stick all the stuff you'll need. A dozen 3000AH batteries sounds great until you're sleeping on the floor because there's no room left for a bed. Is there a compartment that can house all this stuff? Will the server rack batteries fit? Are you going to have to make space? Physics can be pretty unforgiving.

5: Pencil out what you think you need and throw it at us so we can tell you what you've missed (because we ALL miss stuff the first go-round :) ) and help figure out which parts and pieces you're going to want to get.

Well that's the thing about solar systems, there is no 1-Size-Fits-All answer. Your system will need to be designed to fit YOUR needs. When you design and built the system, it's not going to be the perfect system for me, or Will or 12vInstall or anyone else, but it Will be the right system for You and that's the goal.

As for where to get started, let me throw my standard blurb in here to help point you in the right direction. There's going to be a lot of math and research involved, but that's going to be a LOT cheaper than just buying parts off of someone's list and finding out that it doesn't do what you need.

Don't panic on the Power Audit, you'll actually be doing that a few times. When you do the first pass put in ALL the Things that you might want. AirCon? Sure. Jacuzzi? Why not. MargaritaMaster-9000? Go for it.

The second pass will be the "I Absolutely Need This To Survive" list that isn't going to have much on there.

The third pass will be the "This is what is realistic" audit that you'll use to design the rest of the system.

The Power Audit is going to tell you 3 primary things: 1: How big does your inverter need to be to power your loads? 2: How much battery bank do you need to last $N number of days with krappy weather? and 3: How much solar panel will I need to install to refill those batteries in a 4 hour day (the average usable sun hours rule-of-thumb).

Once you know what you Want and what you Need and what your budget can Afford there will be somewhere in that Venn diagram where those three things meet.

After that, THEN you can start looking at parts.

Yes, it's a long drawn out process, but it's worth it in the end. Not every house has the exact same floorplan, not every vehicle is the same make & model, and not every solar system is designed the same.
 
Yup, I laughed!

OK, a few thoughts:

It's a 8'x16' fully lofted prebuilt. I want to do full solar.

OK, that's a reasonable goal. Let's take a look.

Double split ac/heater

I'm going to assume you mean a mini-split and not 2 aircon/heaters. Even if you just do a single 12k BTU (1-ton) on 120v that's still going to be about 1500w + startup surge to power. Right there you're looking at the 3000w range of inverter.

Refrigerator
2 outlets
Easy enough.

1 instant water heater
Oh gods! Now you're talking SERIOUS power. They may not use a lot of juice all day long, but when you turn on the shower they wan ALL THE WATTS NOW!!! Seriously consider going with a propane unit for that. We have a saying in the solar world, "When it comes to heat, ANYTHING BUT SOLAR!!" because electric heat requires a lot of wattage for a long time which makes battery capacity large and expensive.

Same with your stove/oven, consider just plumbing in for propane and connect your on-demand water heater to that. Then get a large tank.

Things I've purchased:
3-100w monocystaline solar panels
That's not going to provide much of anything.

1000w power inverter

That'll do lights and fridge, not gonna start an aircon unit, will just cry looking at a water heater.
12v 1280wh type(I can't remember hot so spell it it's odd )
LiFeP04? aka LFP aka Lithium Iron Phosphate? 1280w sounds like a lot but that's a bog standard electric heater for about 45 minutes.
Controller
MPPT? PWM? Does it have USB ports on it?

I have 1-not a great idea of how I'm calculating this or how much power the mini split (that's the name) uses because I don't have it yet. Or how much poser i need for what else.

When you're looking at the specifications of different models, there will be a list saying something like 115v AC @ 5a or maybe 5a Run, 15LRA. Those numbers mean something. Take the voltage (115v) and multiply by the current (5a) and that will get you running watts (575w with this example). That will tell you how hard your inverter needs to work. Next guesstimate how long you want to run it in a day (6 hours) and multiply again (575w running X 6 hours = 3450watt-hours a day to run it.) As you can see, even this little example aircon wants 3x what your battery holds for a single day.

I have no idea how many panels or watts I need or how long is to long to have backed up. I would like no less than 3 days..
The power audit form in the Resources section will help calculate all that. Don't panic.

This power inverter how does that exactly work?

The inverter takes your DC power batteries and automagically converts that to the 110v AC power that you're used to getting in your home. An inverter can only do so much based on how large it is, so part of the power audit will tell you how big your inverter needs to be sized for to supply all the loads being turned on at once.

Can i do a system for just the power and then a separate one for everything else?
Everything is the same power, not understanding what you're trying to say.


If it does have a Chance of going good then I'm going to need some help in finding the math and the best usage of energy or for the life of me I can't picture the ways to wire and the differences so it's not making any sense which way to do it. Or how do I wire the inverter to the breaker box? Still haven't found that one yet. Like diagrams, mathematics and charts that are simple

Start with figuring out what you need to make everything happy. Then you pick out the parts. Then you figure out what size wires go where. The size of your system is going to determine what wire sizes and fuses you need.

Read through my blurb a few times, make a few passes through the Power Audit form, and we'll go from there. Most importantly, DON'T BUY ANYTHING until you've got a plan and a budget.
 
So to cut it short I'm going going to be moving off grid. It's a 8'x16' fully lofted prebuilt. I want to do full solar.

Things I need to power:
Double split ac/heater
Refrigerator
2 outlets
1 instant water heater
1 light

Things I've purchased:
3-100w monocystaline solar panels
1000w power inverter
12v 1280wh type(I can't remember hot so spell it it's odd )
Controller

All from temu

Now hear me out about that in a few.


I have 1-not a great idea of how I'm calculating this or how much power the mini split (that's the name) uses because I don't have it yet. Or how much poser i need for what else.
I have no idea how many panels or watts I need or how long is to long to have backed up. I would like no less than 3 days..
This power inverter how does that exactly work?
Can i do a system for just the power and then a separate one for everything else?

There's more questions but I'm sure some will be answered anyway. I'm trying to let myself get settled but I'm having a terrible time navigating it all or finding just the mathematics for starters.

Now the temp thing...
I've got some good stuff on there for well below price point. I'm not saying it'll be good or bad but either we'll get a good laugh or a good cry when we find out.

If it does have a Chance of going good then I'm going to need some help in finding the math and the best usage of energy or for the life of me I can't picture the ways to wire and the differences so it's not making any sense which way to do it. Or how do I wire the inverter to the breaker box? Still haven't found that one yet. Like diagrams, mathematics and charts that are simple

Thanks y'all.
Laugh! I about choked when I read instant water heater, 12 Volt and Temu. 😬

Wait till @sunshine_eggo sunshine reads this he's gonna have an IBS flare up. :poop: :ROFLMAO:

Maybe you can find some clever way of putting that equipment together sell it make a little bit of money do some more "research" on solar/electric and then buy some real solar equipment emphasis on research. :unsure: Before spending $$$ on solar equipment.
 
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Yes, like wow, what everyone else said. One thing I noticed is that you have a refrigerator listed, but no mention of what you will cook with. If you are getting propane anyhow for cooking, that might be a good reason to use propane to heat the water. If you are wanting to be totally fuel free i.e. all solar, you would be better off powering a heat pump water heater. The only issue there is space. Regardless, a 12v system is likely not to cut it even without hot water requirement.
 
12v is just fine. You just need 10 separate 3000 watt inverters and $3000 in wire,$800 in bus bars, and $400 in lugs, $2000 in fuses, plenty of space and a love for roasting marshmallows on warm cables..

Just remember, just because the insulation melted off doesn't mean the cable doesn't still work. After all that is exactly how a toaster works. You certainly can take a couple ideas out of the old knob and tube playbook and use them. :ROFLMAO:
 
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We have a tiny system like this in our shed. 1000 watt inverter and 300 watts of solar, but 2 100ah LiFePO4 batteries. It works great for the shed, but would need a lot more solar and battery if we wanted to live in it.

We run lights, radio, sewing machine and a box fan. Just leaving the inverter on over night uses 8% of the battery capacity. Running the fan all night uses 30% to 35% of the battery. The 300 watts of panels are enough to replace about 30% of the battery capacity on a good solar day. If we use more than 30% of the battery we need a couple of days to recharge fully, or we have to supplement from the grid or a generator. It would take 3 days of good sun to recharge a fully flat battery, but only if we don't use any loads while charging.

I would say build what you have, but realize you are gonna need at least double the solar and battery just to run the refrigerator. And a generator whenever the smallest clouds drift by.
 
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Woah hold up time out.... OK some of y'all are thinking mansions and tons of things.... cooking is done outside really because it's off grid so no stove. Am looking into a wood stove as backup or main use. Instant water heater not a must I have pots. So that's out. It's a low watts I believe but not necessary. I'm using rechargeable solar lights that can be used in a dual manner and recharged and have several to change out to save the other energy. I have several power banks to charge my phone that solar and battery charge. There's an 8w diesel heater for backup as well. There's nothing inside it I'll build around the solar needs. I'm going off grid and trying to live off the land. No washer I do have a plug in dryer thing but not necessary if there's heat. I have plug in censor lights that charge and can be turned off and on if needed and backup of those if needed. Solar lights are all around the house already. I do need heat tape to run for the water tank. And I put not a single paragraph... yeah
 
Things to know:

Watts = Volts X Amps
Watts delivered over an hour gives you watt-hour. Example: You want to power one 60W incandescent light bulb at 120vAC. If you run it for 1.5 hours you used up 90Wh. It uses .5 amps. Say you want to power it with a inverter that runs from a 12vDC battery?
60W/12v=5 amps. For the 1.5 hours you will use up 7.5ah from a battery. This of course does not take into account losses occurring in conversion but it gives you a starting point.

So lets look at your comment about a heat tape. These are often 5 Watt per foot or for a 25 ft tape you can figure 125 watts. Lets say it cycles on and off for a total runtime on a frozen day/night of 10 hours. That is 1250wh. Or the equivalent of a 100ah 12v battery capacity. If it is a lead acid battery you would need 2 due to the need to not use more than 50% of capacity.

So the math is pretty simple when it comes to loads and supply. The difficulty comes in with getting an accurate daily load versus solar power ability to meet it.
 
So to cut it short I'm going going to be moving off grid. It's a 8'x16' fully lofted prebuilt. I want to do full solar.

Things I need to power:
Double split ac/heater
Refrigerator
2 outlets
1 instant water heater
1 light

Things I've purchased:
3-100w monocystaline solar panels
1000w power inverter
12v 1280wh type(I can't remember hot so spell it it's odd )
Controller

All from temu

Now hear me out about that in a few.


I have 1-not a great idea of how I'm calculating this or how much power the mini split (that's the name) uses because I don't have it yet. Or how much poser i need for what else.
I have no idea how many panels or watts I need or how long is to long to have backed up. I would like no less than 3 days..
This power inverter how does that exactly work?
Can i do a system for just the power and then a separate one for everything else?

There's more questions but I'm sure some will be answered anyway. I'm trying to let myself get settled but I'm having a terrible time navigating it all or finding just the mathematics for starters.

Now the temp thing...
I've got some good stuff on there for well below price point. I'm not saying it'll be good or bad but either we'll get a good laugh or a good cry when we find out.

If it does have a Chance of going good then I'm going to need some help in finding the math and the best usage of energy or for the life of me I can't picture the ways to wire and the differences so it's not making any sense which way to do it. Or how do I wire the inverter to the breaker box? Still haven't found that one yet. Like diagrams, mathematics and charts that are simple

Thanks y'all.
You can see the system i have in my signature below.. I run in an RV

2 Mini Splits
1 120v Refrigerator
TVs Computers
Lights and stuff

But to be reasonable the solar I have can not alway recover in 1 day .. I can run off grid for a time, but grid/gen are still necessaties from time to time..

All this is w/o hot water coming from electric.. Now, i did do that when I do not need mini splits as much .. When i traveled up north and the weather was 50-70 everyday .. Sure .. I could heat water with electric (BUT NO WAY ON DEMAND!) I have 6000XP that give me 240v split into 2 3000watt lines.. and there is little to no chance I could power anything ONDEMAND that would come close to my little 10gal tank heater in the RV that can do GAS and/or Electric ...

Your goals are achivable .. But the path forward is going to require a MUCH larger system ..

I can get you numbers for most of the stuff you have listed if you want to start building some kind of energy audit to get a real idea of what you need..

Matt
 
1. Do the Audit - learn what the total daily weekly monthly power requirements are going to be for you.
2. Then use PVWatts - plug in your location - see what PV it will take to get the total monthly power needed from step 1 - for off grid use December.
3. Then you can start the planning of a system - how much battery to hold 3-5 days of daily energy use. Will your batteries be in a warm place - LFP can't be charged below freezing point. Should avoid being over 30C/86F too. (FYI).
4. What inverter to output the required Max instantaneous output * the inverters use power just to be on, you need to add this into step 1 & 2.
5. Panels, fuses breakers, safety - we can help you with this part, when you get to this stage.
 
Woah hold up time out.... OK some of y'all are thinking mansions and tons of things....
My perspective is from the simple RV life. Takes a lot to run a compressor. Six hours of good sun needs to run the fridge the full 24 hours.
Propane absorption fridge takes far less electric power to run the controls.
 
Hey good luck on your build! I don't know much, and no way could I ever figure out an energy survey. I do know I have 1500 watts of panels with a really great Outback FM 80 charge controller going into 3 x 100 ah 24 volt LifePo4 in parallel, with a cheap {but very good} 4000 watt 24v inverter.
I run my entire house except hot water heater on this.
1.) full apartment size Refrigerator / freezer
2.) lights, tv, Swamp cooler & misc. electronics
3.) 1 hp shollow well pump

I wired all my heavy loads directly to the inverter and out through an ac distribution panel.

Even on very cloudy days a couple in a row, my batteries are never below 25 -30% just before sun up and most mornings they are closer to 40% - 50% at first light.

It's pretty easy to figure it all out if you focus on the best quality you can afford and knowing what you can pinch a few pennies on and what you can't. I spend the bulk of my $ on decent batteries and a good charge controller which has stood the test of time by lots of users for many years!
Panels are cheap and if you spend the time I did researching you can find a great less expensive inverter for under $500.

You will get out of this what you are willing to put into it as far as study and understanding what and why you do what you do in building a system. If you don't spend much time studying and just spend $ slapping something together, you will get what ever you end up with.
Quick and fast = troubles that last
Take your time and learn as you go = Stuff that last and won't make you go broke
 
Instant water heater
There are some that are in a reasonable range. The draw on these goes somewhere around 3000 watts to 18,000 watts.
If you are fine with luke warm, low flow showers, or just hand washing, This isnt as crazy as many think.
Its about expectations.

I have my 50 gallon water heater on solar. I took out the 4500 watt elements and put in 1500 watt ones.
It is working perfect for me. As hot as it was before.

So if you got space, a regular tank water heater is the best idea for solar IMO.
 

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