After reading some of the comments below, I have noticed that we have some new viewers here that have not watched my other videos. Many of my efficiency and irrandiance equations are covered in other videos and my book. The video above is great for estimating how much power you need, but you can go much, MUCH deeper into these equations. My book covers various losses in a system, battery efficiency and more. If you want to calculate total system efficiency, watch this video: kzfaq.info/get/bejne/htCIoc6ZvcfdqYk.html If you want to learn more about faradaic or coulombic efficiency of batteries, watch this video: kzfaq.info/get/bejne/f9J2n8iC2LKuqmQ.html If you want to learn about cost of a battery with factoring in charge cycle life (which can make expensive batteries look cheap, and cheap batteries look expensive in the long run), watch this video: kzfaq.info/get/bejne/abyFa66knbisg5c.html I hope this helps! This video is GREAT for estimating a solar battery and array here in the united states, but if you are near the poles or dealing with local climate conditions that limit solar, you will need to watch my other videos to calculate your system. Also, the SCC needs to be rated at the OUTPUT, with the working voltage of panels or the nominal voltage of battery bank. Voltage open circuit is for sizing the SCC input voltage and headroom figures. Different equation thats covered in my other videos and book as well. In great detail. *Does off-grid solar confuse you?* Check out my DIY friendly website for solar system packages and product recommendations, and so much more! www.mobile-solarpower.com *Join our DIY solar community* #1 largest solar forum on the internet for beginners and professionals alike: www.diysolarforum.com *Check out my Book* Best-selling and beginner-friendly guide to 12V off-grid solar! amzn.to/2Aj4dX4 If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Energy! They will price out a system and get your house offgrid: ts.la/william57509 *My DIY Solar Equipment Recommendations (Constantly updated! Check here first):* 12V/48V Lithium Solar Batteries: www.mobile-solarpower.com/solar-batteries.html Complete Solar System Component Directory: www.mobile-solarpower.com/solarcomponents.html Complete 48V System Blueprint: www.mobile-solarpower.com/48v-complete-system-blueprint.html Plug-N-Play System Recommendations: www.mobile-solarpower.com/full-size-systems.html Complete "Add to Cart" 48V System Kits: www.mobile-solarpower.com/complete-48v-solar-kits.html DIY Friendly Air Conditioner/ Heat Pumps: www.mobile-solarpower.com/solar-friendly-air-conditioners.html *My Favorite Online Stores for DIY Solar Products:* *Signature Solar* Offgrid One-Stop-Shop. Best Value 48V LiFePO4, Victron and Offgrid Specific Heat Pumps: www.signaturesolar.com/?ref=h-cvbzfahsek *Current Connected* SOK, Victron, Mr.Cool Heatpumps and High Quality Components. Fantastic customer support: currentconnected.com/?ref=wp *Litime* My favorite 12V budget battery!: www.litime.com/?ref=XBIA62RFcalHns *Epoch Batteries* My favorite high-quality 12V battery: www.epochbatteries.com/products/12v-460ah-lifepo4-battery-ip67-heated-bluetooth-victron-comms?rfsn=7352625.50494d *Renogy* A classic 12V solar store that has been around for ages! DC to DC Chargers and more! renogy.sjv.io/n1VjXx *Rich Solar* Renogy's biggest competitor! Similar products, but at a better price: richsolar.com/?ref=h-cvbzfahsek *Battery Hookup* Cheap cell deals bit.ly/2mIxSqt 5% off code: diysolar *Contact Information:* I am NOT available for personal solar system consult! If you wish to contact me, this is my direct email: williamprowsediysolar@gmail.com Join the forum at diysolarforum.com/ if you wish to hang out with myself and others and talk about solar *FTC Disclosure Statement and Disclaimers:* Every video includes some form of paid promotion or sponsorship. Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these. My videos are for educational purposes only. Information is subject to change/update at any time. Electricity is DANGEROUS and can kill. Be smart and use common sense :) DIY Solar Power with Will Prowse is a participant in the Amazon Services LLC Associates Program, An affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com

I am a well educated old fart, with lots of math, computer and physics knowledge under my hat. As such, sadly I am skeptical of young folks trying to teach me anything. Your videos have completely blown that skepticism out of the water. Excellent videos. You have a huge fan and a new subscriber. Well done, thank you for this info.

I've watched literally 100's of solar videos trying to determine the size necessary for my offgrid solar needs. Will, you are the first to explain it so a noob like me can understand!! Keep up the great work son! You found your calling in life! Fantastic job!

I’m a retired marine engineer. This guy has the best , well presented instruction video about solar power for RVs I have seen. Thank you for all the great help with solar for our camper.

As a retired building contractor with decent electrical skills, your showing us great new products and how to hook them all up. The dots are getting connected now as we get closer and closer to main stream solar. Great job young man

Will, I've followed you since you lived in the Toyota RV a couple of years back. You are going places. Makes me feel good. Your not touching drugs or alcohol is paramount. Wish more young people behaved like you. Nobody owes you a thing. You did everything on your own. Respect!

I have been struggling to figure this out for months. I am a blacksmith. I make things hot and beat it into submission. Current is like a slippery snake and won't stay still long enough. Thanks for making this simple. Can finish my camper build now.

My objective is simple, set up a solar powered exhaust that will run for 24 hours a day. You have given me the know how, to select the appropriate solar array, battery, and controller. Thank you Sir!

I have been looking for a sizing guide like this for a while, and you have made it easier for me to understand what I need to do. Thank you!

Hi, i have reached the age of 62 with very little understanding of electric and the part it plays in my life. Your videos are both informative and interesting . I am inspired into new learning and will be buying your beginner friendly book. My first project is to set up a small solar powered system to give me lighting and small use of a power tool in my hand built shed on my allotment in west yorks. Thank you, you are a shinning example of your generation

I really like the way you make complicated things easy to understand. Thank-you for your video!

Dude, you are you inspired and it's awesome. It so cool to see someone who's found their mission and is living it day in and day out. Awesome job, Amigo.

Just got your book today. Read one page and instantly knew i made the right choice. I am doing research for my autonomous lawnmower project and the book along with your videos are a big help.

Your videos are so clear, organized, detailed and helpful, without being overwhelming. You are a great teacher!

I love how enthusiastic you are about this subject. I can tell you are really into it and have tons of knowledge you want to share with everyone. I’m just getting into this and your videos and website have really helped me in this.

Just in time I found this channel that I have been looking for for a long time. Thank you for your cooperation!!I glad that.

Will's explanation of sizing your solar power system is the best one that I've ever seen (or read). Thank you!

No one else on KZfaq can keep our attention with a simple white board ! Great job 👍🏻🇨🇦

Kudos kid. You are certainly beyond your years. Your explanations are so easily understood. First, thank you & second, keep up the outstanding work.

Just a shout out….i have purchased your book via amazon in the past. Between your book/ videos you have literally provided me with a zero bullsh*# education to support myself in my field for work. Appreciated

This guy is fantastic, the amount of things I've learned from a few videos compared to how many others I've watched and grasped little to nothing is amazing, your a god sent my guy. Great content.

I really appreciated your breakdown of every area. You explain each aspect so much more faster and easier than other like videos. Top job. Many thanks for your contribution. Much respect.

You are a very bright young man. I am FINALLY beginning to understand how this whole solar thing works. I might have to watch this a few times before I retain it and understand it all. But YOU have most certainly been a great tutor and a blessing. Keep on keepin' on young man.

Thanks so much for the videos Will. You are an excellent teacher. I was scared to death of electrical projects prior to your videos. Now I’m piecing my solar components for an off grid system. Totally confident it will be successful. Keep it up sir 😀

Makes me realize what an amazing job the power company does and how much we take it for granted. I was working on a project to power a small window A/C for 6-8 hours a day, so all I have to do is take your example and change the numbers. Great video.

Wow, am I glad I found this guy's videos. No one and no video I have found before explains things so well. THANK YOU

Amazing clarity of mind for such a young fellow. Respect.

YEEESSS!!!!! Thank you for the amazing video on sizing a system!!! Every one of your videos I watch gets me one step closer to going off grid- with CONFIDENCE!!!!

I think I have asked this to more people than I can remember, you are the first person to answer this intelligently, yet simple enough to be understood. Thank you for that, I love your videos❤

Will saves the day -- again! Yes, "It's so simple," when you aren't as confused as heck! We are newbies at this and have been all over the net and KZfaq till our eyes are crossed trying to property size our system for our cargo trailer conversion. We are in our 70s with limited $$ and can't afford to make a mistake... So Thank You for clarifying this so *even I* can understand it! You are a treasure... We are definitely buying your book. ~ Kir in Tennessee

Thank you for making this video. It has answered all the questions I have for what I'll need for when I go back out on the road. The math made sense, and having it all there on your white board as a visual aid was super helpful too. 😁👍

This was massively helpful! We've been operating in "guessing" mode for awhile now, trying to upgrade our 20+ year old off grid system. We have dinosaur components, only just recently discovered there were different charge controllers (PWM vs MTTP) and upgraded. Our current battery bank (lead acid golf carts) is aging, going into their 6th year, so we've been trying to wrap our heads around not only the newer tech of lithium batteries, but, really, for the first time, trying to understand our real system requirements. Again, such a helpful video, thank you! :)

Really I have been in the field for almost 10 years but from you I get some thing more especially when we come to calculations of solar panel selection, battery selection and controller selection.

I'm basically a noob for all these, but i must say you made it so easy to understand Will! Thank you so much! :D

I’m an electrical engineer and I have to say that you’re a great teacher! Have you thought about a career in engineering? Well done. Please the videos coming. I’m especially interested in RV applications.

Hi Brillent video & well explained. I am a solar licienced electrical/security contractor in ireland & it’s great to see someone that does videos like you! Well done! Rgds mg.

Great job, I’m 70 and starting an RV van build. I’ve been most anxious about having to outsource the electrics because of my lack of knowledge with these kind of systems. This one vid kicked me into a DIY mode. 🙏🏼

You never disappoint Will !! This was a VERY helpful video, thanks!!!

This is one of your best videos yet. You are extremely smart for your age. I have been working these same numbers over for probably ten plus years and having to rework them as technology changes so I can map out the system I'm going to install when I finally do go off grid "ish". I'm planning on using my latitude and summer vs winter needs to balance what the power company has to pay me for the array (20kwh) I'm going to install. Using the three day buffer for charging my house batteries I'm hoping to average $200.00 a month in income from the grid. Your videos are very informative and I love your energy. Keep it up.

Wow, you are a very eloquent person who gave me the exact answers to what I need in order to determine what load-size battery / batteries I need. Boy . . . you nailed this spot on. Thanks plenty for being of great help. Very useful indeed.

Hey Will, you should do an update video on this with the latest tech/server rack batteries. A good load to add would be a refrigerator since it's running pretty much 24/7 as well as a mini-split heat pump.

Awesome info ..love your down to earth fact based honest style and love how you have turned your passion into a revenue stream also! Thats living the American dream! Im learning a lot about solar and off grid systems...just watched a video of a tiny house using solar and bio gas for their stove lol.... and this is definitely one of the best channels....my top channel for specs and detailed info on solar and related! Keep up the great work! God bless :)

Been a while since I've needed to use Ohms Law. This was a pleasant refresher.

For a you person you are very clued up. Enjoy your passion, I'm just getting started into solar i'm 58 and its refreshing to see a young person with a positive outlook on life.

Hi Will ... new in the industry and far away in South Africa, but this has not stopped me from watching your video's :) great information you provide in the solar industry ... great stuff and thanks for all that you share with the public ... i know where to go now when requiring info in the solar world ... thanks again and keep the good work up ... greatly appreciated .. Shaughn

Dude, you broke this down Barney style perfectly! Even a Marine understood everything you went on about. keep up the good work, love ur vids

Thanks for you vids, Ive learned more here than in college from lecturers with grandiose notions. Im curious if you have ever looked at a combi pv/micro wind turbine off grid systems in order to utilize the notion of more sun in summer and more wind in winter location dependent ofc too. i would love to see how someone like you would design and implement such a system.

Thanks for putting up this resource. I'm a solar newbie and it's really helping me make sense of the basics.

Thank you so much for your videos. Particularly the beginner ones. Clear, concise and packed with information. I purchased your book as a reference. Hope you can keep going with this.

Wow: Will. I am impressed. you have a gift for Energy.. I have been studying Solar for several decades +; I also taught at a jr. college. I live next door to the Grand Canyon west rim, and everything is Solar. Your approach to instructing is ( incredible) ...Thanks' I will watch more and recommend it.

Another great video 😀 You answered some questions I had. Thank you for sharing your knowledge 👍😎

Very clean and to the point battery and solar panel sizing ever in KZfaq. This topic has been thorn on my side for long time… and here you just solved it! I’ll put these formulas on Excel and have fun with it🙃

I lost count of the times I have asked this question, and the many people who either don’t know it well enough to explain it or don’t want to, your humble intelligence is admirable, thank you for your videos, the best in youtube❤

Excellent video Will! I’ve had a solar system on my camper van for about 5 years but only used it to charge phone, tablet and other small items. I’m now considering a 12V fridge/freezer so I knew I had to upgrade. Your video gave me the knowledge I needed to make the right choices in that regard.

Thanks for making this so understandable. 👍👍

Thank you Will, I appreciate how you explain a complicated system in such simple terms, that even I can understand .

I like the clarity in explanation. Makes lots of sense especially for DIY enthusiasts venturing into solar space - keep up

Dude, nicely put. I appreciated. Like your KZfaq channel.

Another option if you want to use solar is like what I did to my house. I renovated the whole house over 5 years and as I did each room, hallway and common rooms I installed a separate wall sconce light and plug just inside each room, one on kitchen counter plug and 2 outside lights. These circuits went to a separate 8 breaker panel I installed in my utility room. The grid system was installed just like it should be and fully functional. The secondary 8 breaker panel was connected to my solar panels, inverter and batteries. These wall sconce lights and plugs are what I use primarily, I have LED lights in all rooms and hallways plus I have a plug in each room if I need to use. The one in kitchen I use for toaster and kettle. I use grid power for fridge and stove, heating and vacuuming mostly. At anytime I could add more to my solar as I expand it to accept more of what's not hooked to it. If my solar ever runs low I just simply use the grid system which is right there. Just seemed like a good way for me to control what I use. It works for me.

I've been following you from Papua New Guinea until I lost track of you. I'm glad I'm with you again now. Thanks alot for your down to earth Explanations. It is really helping me Quite alot in this part of the world. Thank-you once again.

Your knowledge is supreme and you are so fluid with the most thorough presentation of information. Respect!

I was thinking an excel spreadsheet with these formulas could make it easy to play with the numbers . I have one going for my usage on appliances after testing them with a kill-a-watt to see where the waste has been and try to scale things back. It has lead me to focus on sealing my basement foundation since my dehumidifier runs almost constantly at 600 watts.

Added this to favorites. I suggest that people bordering Canada and up, instead of bumping the solar panels by a little, they should double the amount, from 480W to 960W (1000W), because during winter, you will only get around half the sun power at most, than during summer. Also, if you live in a really snowy region, unless you are ok with cleaning the snow off your panels, you might want to invest in some panel heaters, to melt the snow and ice that will form on top of the panels, which means you might have to bump the battery bank AND your solar panels by 20 - 30%. The same calculations for the AC in the summer apply to people living in colder climates, but for an electric space heater. And with the additional costs for countering the dimmer sunshine, it could get pretty expensive to live up north. People near the equator are truly blessed (and also add the ability to grow food throughout the whole year). Edit: grammar.

I really like Will. His enthusiasm is contagious! :)

Thank you , you explain things so that the very new beginners are able to follow along! Thanks for taking the time to help!

Thank you. You made that super easy. I'll check out your other videos. Subscribed.

This video actually helped me understand better what has been difficult for me to grasp with respect to solar system sizing. Thank you!

I'm happy to see you circle around back to the smaller setups and calculations

I was looking for something like this it's really interesting 💖

Looking forward to your home based system design.

I am a retired electrical engineer from a senior position of power sector. Appreciate the video highly , best wishes for the young engineer.

Thanks for the help figuring my way through the solar industry

Hi will, love your videos you are a great person, I like the tone of your voice.regards

"5000 Wh can power a life". Classic

Your hand writing writing is Perfect ! Nice info !

You really produce some well-informed videos thank you. If you need battery cables made for a specific length you don't have the tools automotive parts for instance Napa pre make your battery cables whatever length you need and whatever gauge wire. This can be extremely helpful if you're out on the road and you need a cable don't have the tools to build one

Great stuff. Would love to see a video on setting up a system for a window air conditioner where you run it on minimum batteries. Meaning running it in the hot sunny part of the day from solar.

I love watching your videos. You made it so easy to understand. I'm building a camper van and I already have 2x 138 Ah Valence lithium batteries and MMP Solar 12v inverter. I also got dimplex 500w baseboard heater to warm up the van. Is it gonna be enough?

I am new to this channel. Omg...you blown me away. Such a clever young man. Amazing. The best tutorial ever. Thank you Will 👏

A brilliant explanation this is the first time that I’ve actually understood what is required, thank you

Hi Will, Thank you for making these videos. As a city dweller in Ohio I know lots of people who want solar power. From your videos I always recommend a grid tied 48 volt system, with as many panels as they can fit on their roof. Being in the city even with a small bit of land, theft is a factor. That makes ground mounting an issue. Any rate, I am curious, if I use 562KwH on average per my bill, and install a 10,000Kw grid tied solar array (let's assume no batteries) am I doing more harm than good? In more words. Should I try to spec my system to be all I need? Or, if I have the funds, should I set up my system to feed back into the grid? I hope my questions made sense. I am not a wordsmith. I am just a basic American human who wants a grid, but also thinks it's possible for me to over buy and feed into the grid as help, not a hindrance. I mean, electricity is only theory. Also, for myself I will have batteries for my needs, but would be feeding back into the grid during peak hours. Side Note: just as I pay in taxes and license fees for roads. I don't mind paying transmission and distribution fees to keep the grid up.

The professor is here. Class is now in session...

This sums it up for me. Read up on local jurisdictions, No restrictions on land and ready to build this really helped me, I had to measure how much Wh I use in a day and record it for a week or three to get an accurate usage for how much I need to run my home with.

Awesome speaking. 100 percent . Clear direct and no wasted words in your video... no joking. I am impressed.👍

I have one question.. Can we install this type of system, say 5kw to a home..With UL approved equipment.. Did you do a video on Ul approved equipment?

Everything sure becomes clearer when you think Watts and Watt/hours! Through out that amp/hour calculation of battery size until last. Sure makes higher battery voltages tempting.

Thank you Will, what a privilege to learn from you. Experience and presentation skills all in one!!

You have thought what I struggled for 6 years to understand. Thank you 100%

bro you are the shit !!! thanks for this plan and simple explanation !

First to comment on your happy smile 😊 Hi William!

Wow! What a great way to think about rough system size you need. Thanks!

Your videos and your explanations are the best on KZfaq. Thank you so much!

Now lets get to advanced stuff - powering your offgrid appliances from tesla or other EV! because if you have 50-100kwh battery standing in your driveway - why not use that?

This is the type of math that needs to be taught in school

Thank you very much fo your hard work and explanations of RV electrical etc.. You have made it possible for people like me to see the light at the end of the tunnel!

How to size a PV installation ? Maximum PV first for winter use, maximum battery capacity based on your budget. And that's all :) Your videos are really great !

Nooo, please dont send me down this rabbit hole of understanding! Just set up my off grid solar teardrop trailer, now I gotta do my house. Not cool man!

that system is overkill for just a laptop

Will's book simplifies all this. Don't get me wrong, his video's are GOLD, but his book adds a bunch of Platinum on top. Love it, love it, love it. Thanks for all you do, Will...!!!

Always thought these calculations were super daunting so I avoided them. U've proven me very wrong, bud. Keep up the awesome and educational content !!!