Complete LiFePO4 Solar Battery System Design (Updated Blueprint in Description) 

This video is outdated!!!! DO NOT USE a battery protect in this system. Updated schematics can be found here: 12v: www.mobile-solarpower.com/design-your-own-12v-lifepo4-system.html *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 best-selling, beginner-friendly 12V off-grid solar book (affiliate link): amzn.to/2Aj4dX4 If DIY is not for you, but you love solar and need an offgrid system, check out EnergyPal! They will price out a system and get your house offgrid: energypal.com/diysolar/ *My Solar Equipment Recommendations (Constantly updated! Check here first):* 12V/48V Lithium Batteries: www.mobile-solarpower.com/solar-batteries.html 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 Systems: www.mobile-solarpower.com/full-size-systems.html Complete 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: currentconnected.com/?ref=wp *Ecoflow Delta* My favorite plug-n-play solar generator: us.ecoflow.com/?aff=7 *AmpereTime* Cheapest 12V batteries around: amperetime.com/products/ampere-time-12v-100ah-lithium-lifepo4-battery?ref=h-cvbzfahsek *Renogy* A classic 12V solar store that has been around for ages! 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 always love after I'm completely amazed at the complexity of what you do, you end it with "See, that was easy!" You have a gift, and I'm happy you share it with the world. Keep doing what you do!

I have 25 years in the 12 volt industry and have been doing projects like you my whole life and in my opinion you do an excellent job explaining everything in an easy to understand way. Thank you for also introducing me to products I didn't know about. Keep up the great work!

You crack me up, I’m old enough to be your grandfather and I can only get 75% of what you’re talking about but I love you’re enthusiasm

I am an electrician for thirty years in a steel mill, I do have DC experience on overhead cranes. You are not hard to follow I have doing this a long time learning terms is the hardest thing. I'm going to keep watching to get familiar with components and terms. Thank you for doing this, I think it's great.

For newbies there is always going to be something they don’t understand and there is only so much you can say trying to keep the instructions and explanations concise. What could be helpful to newbies is to draw boxes with descriptions on your plywood to help them visually digest the big picture of what you are doing and building as they continue watching the video e.g. For the voltage step down converter, draw a box or an outline of some shape or form around the step down converter and write a description of the device in the box, something like: Converts 24v input to 12v output to use for 12v load For the Victron Battery Protect, draw a box around it and write: Low voltage disconnect to protect battery from over discharge (disconnect load at 24v - option 8) For the Victron mppt charge controller, draw a box around it and write: Regulates solar input voltage to safely charge the battery. You get the idea. I know you don’t have much space to work with but some people learn better with visual clues. If you are used to playing around with DC circuits and solar in particular, we all know what a voltage step down converter, a relay and a Victron mppt charge controller looks like but a newbie might be listening and watching but then forgets what the blue device is for or what the other blue device is for or what the grey device is for etc.

I learn more with Will than I ever did in high school. I love the way he explains everything. Thank you Will awesome videos.

"It's very simple guys" Love your optimism

Thanks for your enthusiasm, never loose it! I had the same feeling when I built my portable 550W 18650 pack last year - ‘wow - I did it, this is amazing’. Planning for a new lifepo4 pack, for winter use, -40 outdoor temp. Your input here is invaluable. Thanks a thousand times.

I love the way you do a real video. Things go wrong and you show it and then you show how to fix it. Great video. I'll be building this soon.

Building it in front of us makes us feel that we can do it. Great videos, Thanks!

Will, I love the way you edit out pauses. All business and I appreciate that.

Thanks Will! I am a 78 YO solar student who thoroughly enjoys your tutorials!

Well, I'm so new, my green is even greener!!! You seem like a very intelligent young man! And also seem to know exactly what you're talking about!! Kudos to you!! If I were to build one myself... I'd definitely start from square one with your videos and on up to this one. (56 year old mom and grandma.. lol) My goal is to have at least a used RV and full time in it. Travel as much as I can while I'm able to. So solar power is definitely part of the equation!! Thanks for popping up in my suggested videos!!! 😁😁😁😁 Keep up the great content!!

Love the enthusiasm and energy you bring to your videos. Still got a few years of life left in my old lead acid solar system (off grid 13 years in Spain) but thanks to well explained video feel fairly confident I could convert system at some point in the future. Many thanks (ex telecoms tech. retired).

I'm watching your videos over and over - just ordered my first setup. Thanks a lot!

Can't find someone who can explain this better. This guy is smart and the best teacher. Thank you for your always brilliant videos.

I love how excited you get... This really will make more powerful systems flexible and somewhat affordable.

I can’t tell you how valuable your content is! Incredible wealth of knowledge! I’ve been searching for a good in depth way to understand solar setups and for so long. All of your tips on lithium batteries, BMS, and how to set everything up is worth it’s weight in gold. Thank you so much for the information and keep up the great videos!

Hello Will, many thanks to your video. The explanations were spotless, loud n clear and had Professorial gravity. The amazing fact is that, you did not even refer to scripts and the lecture was flawless with no haas, errs and ahem like what we generally are accustomed to; from XYZ! Bravo, my friend. One other thing that I was hunting for was; a solar powered LiFePo4 BMS. Trust me, No ONE , spoke about it during my entire search for the eluding item, The BMS for PV cell Charger. Now, I’d gather all the pertinent info of all the parts and description, compile it and start a new venture. That said, I thank you, once again for all the efforts you put in to make this video a great success. Sincerely, SK

I've seen a couple of your videos before but really gets me is your enthusiasm over all of this. You can tell it's something you love , passionate about. So thank you for the education. I've got to build me a solar power system for my motorhome and I had thought about buying BATTLEBORN BATTERIES. Then a close friend told me about SOK batteries. So I want to learn more about then and found you. And found I may go with the DIY BATTERIES. It's the cost that keeps me from having this system . But the DIY may fit my budget, thanks to you.

William, you are the most adorable teacher. Thanks for your videos....

Love your enthusiasm and getting all giddy when you're setting this up!

You just earn an honorary PHD in explain step by step with very clear detail. You are a genius.

Thank you for making these videos. Not many people will spend the time explaining and showing how to build these solar systems

I've been watching you for a while, and I'm still a beginner, but I feel that once I determine which direction I want to go with my system your instruction will be invaluable! Keep the vids coming, please!

Thanks that one was fun. once (retired) an industrial mechanic - engineer followed most all of it! Been off grid since 85.

So yesterday I took delivery on my BMS and started to think about how to hook it up, possibly using my Victron Battery Protect. So today I find your video telling me how to hook it up. How perfect is that. Thank you so much Will, you are the best.

The relay idea to bypass the bms was awesome, you are truly genius

It's awesome watching your excitement and passion for building these systems. Keep up the great work, we love it!

I'm a little too beginner to truly understand everything but it certainly looks really cool. You're a hell of an electrician my dude

Hello, I am French and congratulate you for all of your popularization videos on this topic which are really very well done and which explains all the monitoring parameters to take into account and their roles (better than all professionals in the sector). As far as safety is concerned, I would like to advise you to insert circuit cuts in your assemblies in order to be able to isolate the generators in case of necessity or simply maintenance for example (battery, solar panel and load) and finally, when handling with a current of this order of magnitude, do not forget to wear insulating gloves because the direct current is even more dangerous than the alternating current for the heart! Good luck and congratulations.

You explaining precisely "ONE from Thousands"God Bless you!!!!

Nice job,Will! To be honest, I did get a bit lost a couple times. It is a lot to absorb. But the system you built in this video seems to be very close to what I will need for a sailboat system that I envision. So I need to watch the video a few more times. And finish reading your book!

This is one perfect example of a solar generator system. I love this setup esp. the use of a relay. Brillant!

I would recommend rechecking the torque setting on each battery terminal at least every 60 days. They can loosen over time due to the battery going through charge and discharge cycles. This can happen with any rechargeable battery. Who hasn't installed a car battery and a year later the terminals were abled to wiggled. A loose connection will become a heat source under load and can damage the terminals.

I love how he actually enjoys what he is doing. Makes me want to go wire stuff up.

Will explains everything really well. Of course it's not always "super simple", as evidenced by the changing guidance on his website and all the comments in this video. Apparently technology is still maturing in this area, there's new BMS devices that change the way things should be done, in less than two years since this video was posted. I'm willing to learn, perhaps Will could replace this video with the new 'mo better "super simple" method.

You are amazing at what you do man, keep it up learning a lot, the basics can never be too much.

I've been trying to learn solar power and actually bought a short course at Udemy. Today your video on sizing just played on RU-vid and I got hooked. Thanks for the great tutorials. And yes I finished this video and will watch it again.

Will, I love your channel but I Amat a very basic level of solar power and I never worked on a system before. I really want to learn because I watch you enthusiasm teaching so many great ideas and concepts to your viewers. Sometimes you lose me by not breaking down the theory of step downs from 24v to 12v and the need for a battery monitor. Maybe I am just slower learner of these topics but when you talk so fast it is so hard to follow. I just wanted to post this feedback. I love everything you do and your brilliance in solar and electricity. Please keep teaching to us beginners. Ty vm.

Thanks Will! I learn a lot with every video you upload!

With each build video I understand more and with this one I'm just about ready. (Just bought the book but wish it had been available through Google Play). Two comments though. There are several points at which you stop to charge capacitors but I'm still unclear on when/why this is needed and exactly which leads are involved. Second, in other builds you make a point of disconnecting the solar charger before making some changes in a system but other changes are ok without the disconnect. I think I noticed that happening here once or twice, but again I'm not clear on when and why this is needed. These may be general knowledge points but a quick reminder of safety points would be helpful when you are doing full builds like this. Your step-by-step instruction is complete enough that it's likely someone who hasn't seen other videos will try the build and fry something. Might even be me! A link to a reference video or to a chapter in the book would be great. Thanks!

Super Simple Schematic Solar Stoke! You made learning a complex system very straight forward and enjoyable! Thank you for creating this…

You will never go without power young man !! You are a great inspiration !! To me and I'm sure to your generation !! Great job solar man !!

Will: "It's so EASY!" Narrator: It was not easy.

Your content is always so well thought out, Will! You've got another winner here. Thank you so much!

I'm 72 years young and never crimped a wire. Do you think I can learn? I love your videos. You are an inspiration

This is where I'm at... good to watch this video again. Wish I would have gone with a larger inverter, but that's learning on the job

Fantastic video, clear and very informative. You are an inspiration my man, keep it up. You have me hooked!

Thank you for the straight forward explanations of the Solar charging system.

Will, you are the best. Your enthusiasm is contagious and I have learned a LOT from you and your videos. Thank you!

I work in the aerospace industry my head just exploded watching this great information just a lot to absorb

Great job Will. You explained everything very well.

I think I fried some circuits in my brain trying to understand everything.

Excellent video Will. You are a very good instructor. Even if I wasn't excited about technical subjects you always bring a level of excitement that everyone has to enjoy! Keep if up the great work you do please.

I luv your videos your the best! If it wasn't for you i would have never learned what solar was. You have inspired me to build solar because your teachings..thank you..

I like the “oh my god it actually works” thanks Will Great demo !

The only thing I see missing is my ability to buy all that stuff! Thanks a million for your videos, I like how you get excited yourself when doing them. Kutos to you and your research and your brain, Cheers

Watched this on 15 April 2021!!! Awesome info & examples, William!! Thanks for your expertise & willingness to impart your knowledge. I have your Mobile Solar Power book for reference ;but really enjoy watching your videos!!!

Even though this video is 2019, I really want to use this to experiment with far smaller LifFePO4 cells. I originally wanted the 18650 cells but want LifFePO4 chemistry. So many of my home's systems use 18650 physical size batteries and so if I can go Solar-Charged, and replace them all with LifFePO4... omg I would be so happy and more confident! I sincerely hope you would consider re-doing this video with that Beginner view in mind, using small LifFePO4 cells like that 18650-form-factor size. I watch this video over, and over, and over again.

Made it to the end, i love how you are always trying new things as you are making the video, sometime you surprise yourself. Keep sharing the knowledge. larry

That was great one piece at a time!!!! I loved it I could understand and comprehend all of it and I’m just getting started in this!!!! Thank you Dan

Watching the vids you've made about small scale battery banks has been an inspiration for me to build my own power bank and save money over a Tesla Power Wall. I just wish it wasn't going to be so dam expensive for me to build it, even going DIY.

Victron BatteryProtect 12/24V-100A Almost burned my shed down. Was very excited to find this product. Used to protect my batteries on my 1700 watt solar system with 690 ah of battery backup. Unfortunately it would cycle on and off a dozen times before it would finally turn on. Ok, got a defective one. Easy return, new one arrived within 2 days. Within minutes I had it hooked up and programmed. This one was solid....until the batteries were discharged and it triggered a shutdown. The display showed the unit had disconnected the batteries, but my load still had power. As I looked at the app to make sure I hadn't inadvertently triggered a wrong setting, I smelled something burning. Looked at this unit and observed it melting off the wall. Disconnected the power before it caught fire. There is no way I'm trusting this unit to operate without being supervised. Constantly. Too bad. Had high hopes.

"If you can crimp wires you can put this together!" "Now just short out these terminals for a big ole gnarly spark ... " Very informative, though - thanks for this!

Great info Will. First solar component build you've done I was able to follow and actually begin to understand.

“.... guys this is soooo simple!...”. 🙄. You are simply amazing Will! Thanks! 🙏

It was fun to see you having fun with it too. I really like it when people get in to what the love. All the best thank you for video. I bit over my head, but maybe if I watch it enough I will understand.🖒

Ther perfectly describes what I would like to put together. Very happy with the information. Thank you.

Great video, love your enthousiasm! Greatings from Belgium.

Will, you're an amazing young man. Stand strong.

Thank You, the whole concept switch on like a litghtb after your detailed explanation. Wish I could contribute to RU-vid like You!! Keep it going bud, passion shines from You like the Sun

Another great vid. Love your enthusiasm, instruction and insight! You motivated me to build my own system. Thanks for all your awesome content, Will!!

Amazing 😉. I learn something new every time I watch your videos. I’m new to this subject and you have opened my eyes to possibilities. I’m already have a system per your recommendations and it works great!! I like this system best so I may have to upgrade 👍😎 thanks for sharing your knowledge.

This was probably the best explanation a configuration I have seen sofar excellent job

Loved it. Needed to rewind sometimes. But will definitely watch again when i come to build a Lithium system.

I think I read (on aliexpress) that a separate port bms by daly is limited to 8amps on the charge port. I could be wrong tho....? Love when you do long detailed videos. Keep em coming.

I think in this application you would be better served using your BMS on the negative of your solar panel wire. As you wired it up you risk your solar regulator when the BMS cuts out for high voltage. Since you are really only using the BMS for charge protection I think it should work fine on the feed of the solar regulator. I'd like to know how this would work.

That was fun as all get out! My eyes were glued to every single minute of this video! You’re a great teacher!

Well done Will. I have read your book, great for layman. And,for this old EE. I highly recommend it for anyone attempting solar power.

Can you make a troubleshooting video explaining how you figured out each of the things that went wrong in the video and how you came up with the solutions for them? Thanks for the great video!

Thanks for all your hard work. As for following it, yes, to a point. I would have to follow one of your systems to a T and only adjust battery capacity or charge rate within the range of the hardware. I would be the limiting factor not your instruction.I would still be confident with the outcome though

I LOVE your videos. I just lie down with a bag of cookies and soak it in. I even like watching content that is WAY beyond my comprehension. I just bought some Battle Borns because of your videos. Thank you for these great lessons!!!

You know why Like your work its clean clear you can track all wires inputs and outputs without drawing i have learned so much brow

Great Video Will....I really love watching these things...it's makes me feel like I know something about electricity and batteries and solar. However I only have the very basics...W=V*A. I understand what each component in the system does and could assemble it all with your step by step instructions BUT...I would never be able to trouble shoot the system if it stopped working and I would not know when to "short" between 2 terminals to charge a capacitor in BMS or Controller or Converter or Battery Protect Device etc... I also don't know the order of connecting or disconnecting wires from the different components; positive first or negative first. And I don't think this systems and these components are very forgiving if guessing which wires to put where and when. It would feel really great to understand everything but I don't think there is any short cut to learn it. For those reasons, I'll probably have to pay the cost of ignorance and buy the Battleborns with internal BMS to eliminate that setup along with the battery protect. I'll have to use 12 volt (and bigger wires) to eliminate the converter. I wish I could absorb it all, it would really feel empowering. It's like a rubic's cube to me. I understand the 6 different colors and that I want each surface to be one solid color and if you gave me each step for twisting and spinning the cube I could slowly follow it but I could never repeat it without the slow and tedious instructions...I could never understand how to get their on my own. You are doing a good job explaining and I'm catching a lot of it but I don't have enough of the basics to tie everything together.

Great little system that covers all the bases!!! Did you think about another relay for the incoming solar power? When the other relay shuts down it could turn off the solar input as well while using the common port BMS. Thank you for all your work putting out these awesome videos!

Very Cool!! And I would agree, he does explain things well. I like watching his stuff at 2x speed to get the overview and then when I'm ready to try it out I can go back and watch the area I need step by step.

This is a really, really great video! I enjoyed every second of it and really got some new ideas - like building a 24 V system to drive the inverter, and then have a 12 V converter to drive everything else. Too bad it is outdated. I really like your positive energy!

No Will, YOU are amazing 😊 x

You really did an amazing setup. Covered pretty much everything anyone may need safety and feature wise on a small system setup like this one. Nice touch with the DC to DC converter for the 12v relay. Could you calculate overall efficiency for the entire system? Thanks, well done.

You did a great job on this video. Love the fact you didn't take anything out but worked through it as you went. GReAT Job !

This is probably the most important video I've ever seen.

Will so would you rather build your own LIFEPO4 battery bank? Or buy a battleborn? Or Tesla battery pack?

unfortunately all the BMS with separate ports I was able to find has a max charging current of 8A (not applicable for me) ... so the potential problem with the BMS disconnecting the battery from the solar controller and damaging the controller is still there. Any ideas pls ??? thanks

I became lost a few times because of the 1st problem and then adding more stuff to correct the problem then adding more stuff to run 12 volt appliances. lol I'm really glad you post a schematic of this on your website. Awesome Video :) I just hope one day I can understand all this like you do :) PS: I love your enthusiasm.

The BatteryProtect is a MOSFET and cannot block current in both directions. According to the Victron BatteryProtect documentation you should not use the BatteryProtect to switch a load that may run current in reverse, or for capacitive loads such as inverters.

The problem with these system's is their intolerance to that capacitor fill when first hooking up. THe option for power disconnect during storage is not streamlined. Once installed in an RV and integrated you are easily punished for forgetting one thing. The whole process is not robust. Charge controllers need a way to handle the surge and survive a battery disconnect situation without manual intervention. The technology is still in its infancy here.

Ok, I must have missed something ... you have a 24 volt battery pack going to a 12 volt inverter. So does that inverter have a voltage regulator to accept anything from say 10 volts to 30 volts of input.

Great thinking on your feet. I liked the way you kept improving your system design.