How To Size Your Off-grid Lifepo4 Power System

In this video I answer the often asked question about how big our energy storage systems need to be and why mine seems to be so big. I address sizing of the inverters, batteries and the backup generator.
I misspoke when I said the Koi pond uses 35% of my electrical consumption. The actual portion of my consumption is 20% of my total.

[@davepartlow6430]

Thanks Ray, very informative for those thinking of pulling the plug, HA, on the grid. We moved to Hawaii 17 years ago, bought bare land and lived in a tent with canopies for 2 years while my wife and I built our house. No grid power. I'm a DIY guy as well. I started with building my own solar system with a 24V, 2500 watt, 120VAC inverter, and lead acid batteries. Built out house with this system, using a generator rarely. We actually lived very comfortably, even had a TV set up in our outdoor living area. Now, in our home, over the years, I've upgraded our system to a 48V, 4000 watt, 240VAC inverter and LifePo4 batteries. All our major appliances are propane to reduce the load. We average 150" of rain a year, so a lot of cloud cover. 🤙

[@billfraz1]

Ray you have never told us how much in material one of your batteries cost? We would really be interested a detail list of how much each item cost and where we might purchase the items. I think it would be a great video. Thanks for all you do for us.

[@zeteclover]

Ray, you're a gift to those of us getting into the idea of DIY/off-grid energy management. I only found your channel a couple hours ago, and I've already been through several videos due to the clarity of content and obvious focus on transparency. You and Will Prowse are the only two channels I've found where I feel I can deeply trust everything you would currently say. I do have one suggestion: you mentioned in your video about buying LiFePO4 batteries on Alibaba that you don't like the idea of affiliate codes and the potential for financial interests which run counter to your values. I believe you can do both, and would be thrilled to know you're getting monetary value for the value you provide us viewers. Your integrity comes through clearly on video. I believe critical thinkers will be able to tell the difference between you and a common shill, in part because of your transparency and effort to share both the good and bad reviews. Thank you again from a new viewer in Maine. Looking forward to future videos!

[@peterking1134]

I like your thinking on redundancy ! Can never be enough.

[@rickbattle5706]

Great summary. Some excellent real world information. There is no substitute for experience and you have applied your experience and knowledge to build the best solution for your needs. Certainly one size does not fit all. 🙂

[@RayBuildsCoolStuff]

Thanks so much Rick

[@jeremyallard7015]

Hi Ray I just wanted to wish you and family a Happy Holliday

[@RayBuildsCoolStuff]

Thank you Jeremy! That’s very kind of you. Hope everything is going well for you and let’s build some cool stuff next year.

[@USA-GreedyMenOfNoIntegrity]

I am totally off grid on two Sol-Ark 12k's putting out max of 18,000W. The highest consumption I've seen is 15,000W, with 6.25 tons of heat pumps, 5000W water heater, but I will not run dryer and all burners on our electric stove plus oven at the same time as everything else. We don't use the dryer much, so it doesn't really affect us. PV= 20,640W. I recommend 26,000W minimum for PV if you have three plus dark cloudy days in the winter months. 134kWh bank (2000 lbs): 10 ea 16S 280aH batteries connected to 1/4" x 2.5" x 72" silver-plated, copper bus bars. Max charge/discharge 370A or 37A per battery. All batteries designed to handle 100A. BMS's of several brands rated between 150-250A. 400gal LP only for Honeywell 10kw gen. Woodburner for backup. All electric heat kits inside air handlers disabled with toggle switch. Not needed during defrost cycles. I know that below 28F outside temp, I'll need to lights fire. If you want to be totally off grid like us, just skip that $60,000 new truck and you too will never have another power bill with associated taxes.

[@tobyz.3452]

Thank You, Thank You. . this was most helpful. I look forward to watching all of your videos.

[@lindasmith5633]

Another KZbinr made a video that broke down the kilowatt hours and the app hours and all that kind of stuff I don't know how to explain it but it was pretty informative

[@jeremysongs6135]

Great Video Ray, I agree with your approach to autonomy. I am surprised that you haven’t been invited to speak about your Solar and building experience as yet. The people need more Ray’s. The academia people are missing a trick if they don’t get you to lecture on new building methods. Happy Holidays

[@opera5714]

I have PV hot water, dishwasher with heated dry, clothes washer which has its own water tank and all cycles are done with hot water, refrigeration and a couple devices to keep me alive at night. All this is done with an old car battery. I just added a 50AH lipo4 so I can binge watch movies. I'm in hog heaven!

[@bobblack3870]

Great logic. Great one-way communication.

[@tastiger91]

Good planning

[@chrisrichter6327]

Hi Ray, you were talking about high inrush currents from motors starting up. What I am going to do for my next project is to build a large capacity super capacitor 51v bank and add that right at the input of my DC at the inverter. Super capacitors can deliver that super fast current instead of demanding all that current from your batteries. I hope that bit of info might be of help to somebody. Kindest regards, Chris

[@RayBuildsCoolStuff]

I don’t think the batteries are the weak link when it comes to inrush current. The real problem comes from the inverters. These high frequency inverters that we use depend on mosfets instead of large, heavy iron and copper transformers. They don’t like having huge spikes in current.

[@AndyFletcherX31]

You certainly have a large system but as you explained it is appropriate for your needs. I'm offgrid in Shropshire, UK and can run my house off about 5KWh/day but will happily soak up any spare power into my EV and aircon/heating. PV seasonal variation around here is about 7:1 which makes the end of December really difficult and last winter I had to boost the batteries by about 100KWh. There were days I only got 1KWh off my entire 9KWp array! Power resilience is achieved by splitting my house loads across 1200VA and 5KVA inverters and being able to repatch the consumer units onto different inverters if one fails. The 5KVA power limit means I have to do load management but this isn't a problem and has become second nature to me now and I don't have to worry about the high idle power consumption of extra inverters. I also have a gas hob and small room-sealed log burner for those dark and cold days. As you described - you have to support multiple levels of resilience to keep essential systems running and your house warm when things fail.

[@RayBuildsCoolStuff]

Yes, I forgot to mention that my plugin Prius uses 6 Kwh per day as well. Of course I only used 15 gallons of petrol last year and 5 so far this year.

[@elmstrong]

Really good explanation and method, as I previously said, I like your style of doin' these things and appreciate your knowledge. God bless you and take care....

[@SylwerDragon]

Nice video Ray. I'm connected to grid..but i have 2x 5kW Victron Inverter(transformer version) and one 11kW Mpp Solar high frequency inverter.. and i expect in case those 2x will fail i probably will be able connect at least for some time that one as back up..You are 1000% correct..You always have to think with back up in mind ..Also i think if you live in hot climate..at least during summer...every equipment should have additional fan so cool it down..even if it will not start itself.. ppl don't realise that even passive chargers (for example those from Victron) will get hot during summer..and that ''hot'' will reduce life time of this equipment significantly. ,,So in my opinon every inverter/charger should have additional fan working 100% of the time..at least when there is outside over 25-30 Degree if it is below then it isn't as big deal..

[@RayBuildsCoolStuff]

check out my solar shed videos. I climate control my solar shed to never rise above 85f or 30c

[@capfisher6626]

Nice!! Agree with everything except for the usage of gas I just think that if you’re going to spend that much money you might as will be all in electric wise But that’s just my opinion and how I roll

[@Dutch_off_grid_homesteading]

Heya, yes there is more to it as the most people will think about. so it's important that people can get this information so they untherstand it better. alot of factor's to keep in mind. do you use solar water panels or windmill ( not sure how much wind there is in your place ). a netzero house is wounder full well done.

[@sammaimas155]

Ray by my calculations you seem to be consuming about 48kWh/day which seems extraordinary compared to the average US house which uses around 29kWh/day. That's a big energy footprint. I live in Australia and we are energy conscious but we certainly do not deny our selves any comforts and our daily electricity use averages 15kWh/day. We have a 5kW solar array which feeds excess to the grid and we get paid a feed in tariff. We haven't paid an electricity bill since it was installed in 2012, we also receive around $400/quarter for the electricity we export. I am currently working on replacing the AC pool pump with a DC pool pump directly powered off a separate solar array (4 second hand panels) using a MPPT controller which will mean more savings and there are many other ideas as far as cancelling out the Hot water energy use as well. Thanks for your contribution to the DIY solar energy community, You Ray, Will Prowse, Andy from the Off Grid Garage and others are doing a great job of educating others. Cheers

[@RayBuildsCoolStuff]

Yes our consumption is higher than average. We charge my car with 6 Kwh per day and use 10 Kwh to operate the Koi pond. Beyond that we spend a great deal for pumping water on the farm for domestic use, irrigation and watering the cattle. The shop uses a bit as well and water treatment to provide drinking water is a non-trivial amount. Many of these amounts are hidden from an average consumers electric bill as they are consumed elsewhere and passed along in water, fuel and food costs. They also explain some of the importance of having our own system. Out here, more of our energy consumption is directly used and not hidden in centralized infrastructure.

[@niktak1114]

48kWh/day is nothing for a farm. Our farm has used a couple hundred per day before.

[@RayBuildsCoolStuff]

@@niktak1114 pumping water is energy intensive.

[@chrisbritton8326]

Thanks Ray for the video. You gave me some additional ideas and different approaches for my projects. I would some info on that smart start device. Happy 4th brother.

[@RayBuildsCoolStuff]

Do a search for EasyStart.

[@chuxxsss]

Morning Ray, I am planning a show, which will show what happens when the system is to small. Taking it that my shed is off line, and it is winter here. I need a biggest system more invertors.

[@energydreamer5347]

Great share! Great breakdown! Great thought process! Just edited my plans because of this video from one large inverter to multiple inverters for that “what if” factor. Would you mind sharing about the PV generating capacity or did I miss that part in perhaps a different video? Many thanks!

[@user-mz8mq6xe9p]

You could call this video Prophylactic Generator sizing

[@nach335]

The grid is my backup

[@jcagaspar]

Triple redundancy is a good thing,

[@staceysimmons7611]

Still waiting for an inverter video. I love your redundancy. Have you had the same inverters since your system was installed.

[@scotthenderson4376]

Wow I see in comments your estimated use is 45 kw a day higher then the average . I have solar 7.8 kw grid tie and 4k off grid power to my house and with the Fl heat this year I'm burning thru 55/60 kw a day I just can't keep up (my batteries are getting tired) that might have something to do with it. But the 20 year old perfectly functioning A/C is killing me. :(

[@smellycat249]

I would be very interested in the smart start device you mentioned. A quick search only brought up devices for boats and RV’s.

[@RayBuildsCoolStuff]

It is called Easystart and they are sized to the application.

[@psi23k]

Soft start motor starter.

[@Bluntask187]

Heya- can’t seem to find out what kind of battery supply can run an electric dryer to dry a load of clothes… I’ve seen videos that can run them, but it’s only for a minute. It’s like their system can run this that and the other at the same time, but for how long? I’m sure there’s a way to mathematically figure it out, but I’m not even sure how I’d go about it. Just looking for a real world answer of “ you can run a moderately inefficient dryer x amounts of loads on a 48v 100ah battery ( or 5 doh!) “ and that would help me understand. Well, I guess then that leads into the size inverter req’d 😢. Thanks While I’m watching your video, I heard you mention the soft start on your heater. Is there something I can use to adapt the motor on my oil burner? My generator def takes a hit when it goes off! Might be kind of a cool thing as an after market thing if it doesn’t exist that be added to existing power hogs!

[@peterrock2838]

I really enjoy these videos - the off-grid and the construction (diving too). Using the LiFePo4 cells is a much cheaper option than the new rack mounted all-in-one's. Which inverters are you using?

[@RayBuildsCoolStuff]

I got the Deye 8k split phase before solar strong armed the manufacturer into not selling split phase inverters except to solark.

[@energydreamer5347]

@@RayBuildsCoolStuff - I can attest to that being factual. ….. and the S company has them way way way over priced. I have considered purchasing a EU version and attempting to DIY the steps needed to use here in the US. Another part of my equation is the cost incurred to build the DIY system. THANKS RAY !!!

[@52gulfpapa]

Another great video. Can i ask the model of your inverters and where were they purchased? Thanks for the yhe great programming.

[@RayBuildsCoolStuff]

Deye 8k from the OEM in China.

[@52gulfpapa]

@@RayBuildsCoolStuff Thanks

[@ericanderson9004]

Hi Ray, could you wire your generator to just one Deye inverter and the other (two) SMA AC inverter to the generator input of the other two Deye inverters. Thus eliminating the risk of a bang event. And since all batteries are connected on a common bus they will charge. Eric Anderson

[@RayBuildsCoolStuff]

I doubt that would work as the Deye inverters are tied together as a master and slaves for coordinated function. I have seen nothing in their 200 page product manual that would lead me to believe that that is possible. That is some interesting thinking outside of the box though.

[@ericanderson9004]

Yeah, that is for powering your local grid so each inverter is pulling their share of output. Doubt it works that way for charging batteries.

[@marktheunitedstatescitezen185]

Great heads up teaching ! If you could please so kindly point me into the direction or answer roughly on my most used month was in the neighborhood of 320KW for a 30 Day month which is about 10.67KW a Day :- 16 hours we’re a wake is 0.667 KWh & my solar panels are 4 Rich 100W solar Panels my system was to be backup only but then I was thinking Grid Tie In would save me $ a little , I am sorry about my ignorance I watch you & DIY Solar - my solar panels are not yet installed I need the proper inverters , I have 2 Lithium 48v battery banks 1 - 15pcs 3.2v 280Ah & 1- 20 PCS 2.4v Titanite & I have a MRPOW Hybrid 3000W pure sine wave inverter 24v charge controller MPPT Please Help me find a Better inverter please

[@travishodges5179]

Our electric company has a demand charge of 5$ kw for peak times of 6-9 and 4-8, they are training us to only use one thing at a time! Dummies are training us to go off grid!

[@perry9492]

How are you syncing up your inverters? You said you had three and I assume that they dump into a common panel.

[@RayBuildsCoolStuff]

The inverters parallel with data cables and the master inverter samples data from the master battery. The master battery communicates with all the secondary batteries. It is all one big happy family.

[@mackfisher4487]

Water Heating: Have you looked at the possibility of solar water heating, with propane backup?

[@RayBuildsCoolStuff]

That is an expensive and complicated system. Total cost of my propane for hot water is 15$ per month.

[@rkdbm1]

Ray... great videos... you have convinced me to go through Jenny Wu. She has sent an invoice and I am to pay via paypal... is that the way you have done it,,, or is there another way. I am used to seeing a product online, going to their "checkout" page and clicking "order"... is this how others are buying these batteries? thanks!..... Roy

[@RayBuildsCoolStuff]

I pay with a credit card. That way I get cash back.

[@duanehulse2037]

My generator was stolen and I couldn't afford one as big as what I did have but I don't think mines appear sign waved a predator from Harbor freight I guess I need to look at it and see just what it is this one's never been out of the Box yet the one random few hours a couple of times

[@Whoppels]

Have you thought about building a gasifier to run your generator?

[@RayBuildsCoolStuff]

No, not even in passing. Have you done that?

[@Whoppels]

@@RayBuildsCoolStuff No, but it was something I was interested in building. FEMA has a guide on how to build one. Apparently they were used in Europe during WW2 to run tractors when fuel was scarce.

[@MaximC]

I wonder why your videos have only 60 frames per second as option (it seems)... Is it something that you specifically tell KZbin to do ("upload only in 60 fps"), or is it automatic?

[@RayBuildsCoolStuff]

Automatic and unknown to me. I know you can select standard definition on playback to reduce the file size.

[@MaximC]

@@RayBuildsCoolStuff I personally can't. Only 60fps. Which is funny, because why would one need 60fps in 144p? 😄 I don't think I've noticed this with any other channel. Strange...

[@MaximC]

@@RayBuildsCoolStuff It's just that when I'm out and using mobile internet (not unlimited WiFi) - it's not the best thing to be able to choose only between resolutions with 60fps... Strange KZbin behavior...

[@RayBuildsCoolStuff]

@@MaximC sorry about that.

[@silverbackag9790]

@@MaximC s we hat are you babbling on about? 60 FPS is a fairly high frame rate. 30 FPS is standard.

[@KellyLCall]

I just sent you a question by email

[@MaximC]

Wait, how many LiPoFe4 cells do you have?? Sounds like MANY...

[@RayBuildsCoolStuff]

128 cells per system plus some extras for smaller projects. Altogether 278.

[@MaximC]

@@RayBuildsCoolStuff Oh my god, so many. 😳 Cool!

[@wisdomtobias9014]

Pretty expensive fish 🐟 😅

[@RayBuildsCoolStuff]

Very!

[@jalpa9642]

I know a person in OK. who's building an off-grid house w/Solar Power who's running a harbor freight 9500 gasoline generator 24/7 for power. This is his 4th Generator cuz the other 3 quit/died and he got the extended warranty....! =)

[@holgermessner851]

I’m watching some of your and other people’s videos. I do live now in Panama and looking into solar systems. You guy have a very expensive hobby! You don’t use a lot of e-gadgets if you go Solar in my opinion. Here, locals go gas. Gas stove, water heaters etc. to not run into the usual power outages in Panama. I will start with 5kw and see that I don’t end up like most f you.

[@RayBuildsCoolStuff]

Yes we could go more towards gas but then we are owned by the gas company and their ability to deliver the product. uhhhmmm no. lol

[@USA-GreedyMenOfNoIntegrity]

I have 400 gallons of propane to recharge our 132 kWh battery bank from our Honeywell LP 10,000W generator in the winter.

[@holgermessner851]

@@RayBuildsCoolStuff If you live in Latin America and would go all electric, locals would say: typical Gringo people! I did live after re-opening Panama City (8 months pandemic lockdown) in the Los Santos area in an apartment. 10 months we had at least 7 days per month without power for many hours. No power, no light and no water because the water supply at this area was on electric pumps. No back up generator. So I started asking why the mostly Americans wouldn’t chip in $300 do get at least a diesel generator. Answer from around 90%? “Why would I do that?” And the same guys were complaining about the power outages when it happened the most. So I moved away from so much stupidity and got my own land. Still awaiting my permission to build. But if I get it I go solar and have already a 6,000 watt generator I use to work on my house anyway.

[@wt8522]

Instead of the camera pointing at your face, how about point it at the equipment. The inverters, the battery banks and the solar panels.

[@energydreamer5347]

…. just a suggestion - check out his other videos and it shows all the equipment and @Ray doesn’t do any editing - it’s true footage and raw footage and straight from the heart - that’s why people loves this guys channel !!!

[@wt8522]

@@energydreamer5347 Yea, you're right. It's just the thumbnail showed Ray in the equipment room.

[@jeremysongs6135]

Great Video Ray, I agree with your approach to autonomy. I am surprised that you haven’t been invited to speak about your Solar and building experience as yet. The people need more Ray’s. The academia people are missing a trick if they don’t get you to lecture on new building methods. Happy Holidays too.