12 volts VS. 24 volts VS. 48 volts for Off-grid Solar Power Systems

[@TheOldJarhead]

If you enjoyed this video, check out this one too! kzbin.info/www/bejne/qXOakKSnZ7mdoJI and thanks! 😁

[@northerncaptain855]

I retired a few years back and moved full time to my off grid cabin. After maxing out my 12V system, I’ve now upgraded to 24V and realize I’ll probably end up upgrading to 48V. I would have saved money and effort by just going 48V out of the gate. Recently found your channel and find it quite helpful.

[@TheOldJarhead]

Awesome!

[@aheretic]

Good to see you going over the voltage differences again. Something one needs to consider these days with the selection being pretty open and having available "affordable" components now. I was lucky to not start down this road until last year and went down the 48V road. But purchased a charge controller that does all three voltages in case I need to charge the others for any reason. Also run a DC step down 48v to 5v to run a Raspberry Pi and provide A and C USB ports at the equipment mount.

[@TheOldJarhead]

It's great to hear about your setup and how you're managing the voltage differences with your components. Sounds like you've got a solid plan in place!

[@Aaron-vj8kw]

@aheretic what charge controller did you go with?

[@aheretic]

@@Aaron-vj8kw Victron smart solar 150/45

[@TheOldJarhead]

My MorningStar and Outback can be either as well as my xantrac but Victronbis the new kid that is doing well.

[@WilsonForestLands]

Thanks for the mention. I ended up with 4 of those 12 V batteries. When I got my solar and battery equipment I also got a 12v 1200w inverter. I was going to install it a couple days ago. When I started shopping for cables and saw how big the cables needed to be, I sent the inverter back to Amazon. At that point I realized I don’t want to deal with 12v when I start really building my system. 12 V will be fine for the summer at the ranch as I have it but when I set up a more permanent system, I will order either a 24v inverter or think about going to 48 if I decide I want to expand and go bigger. I should start writing down a list of questions for you for our next solar conversation. 😁

[@TheOldJarhead]

Sounds like a plan! Perhaps I should do another Live ;) and happy to help!

[@WilsonForestLands]

I missed your last live but I should be able to make this one. With plenty of questions.

[@TheOldJarhead]

@WilsonForestLands I'll be ready!

[@gabrielglouw3589]

I’m making a handcart solar generator to act as a backup for my gas generator. My plan is to run my fridge and freezer and ONLY that exclusively off solar and battery if the power goes out during a natural disaster. I decided to go with a 24v system for that. I’m glad to see my thinking wasn’t too flawed.

[@TheOldJarhead]

That’s a great choice for a backup system!

[@MississippiHomesteadJourney]

Yes, it's so hot down here on the Gulf coast, I've been using my recumbent exercise bike inside. The heat and humidity drain me too fast to get anything done outside. lol I started out in 2012 with a 24 volt system and still use 24 volts now. I thought about going 48 volt, but the only thing I have that is 48 volts is a Xantrex C-40 charge controller, looks like the one behind you. Back then there was very little 48v, like you said but now there is a lot of 48v stuff. I might change in the future, but just spent a lot of $ on some Victron 24v inverters(3000w), capable of parallel, which can double the wattage(6000) and also get 240v out of them. No more jumper on the hot wires in the breaker box. lol Anyways, great video again. New people to solar should go 48v or at least 24v, definitely stay away from 12v unless it's a very small system, 1000 watts or less. I just bought 2 Redodo 24v 100ah batteries, gonna see how they do and if I like them get more.

[@TheOldJarhead]

Appreciate your kind words! It's always motivating to hear from viewers like you who enjoy the content. Best of luck with your Redodo batteries!

[@TheOldJarhead]

FYI you are correct, that is a Xantrac C40 behind me ;) Replaced it with a Morningstar MPPT back in 2010 or 2011.

[@SuperSushidog]

Great info for beginners! I've been living FT off grid for the last year and a half in my 35ft Class A motorhome so I can give you real world numbers on what a typical FTer will need to power everything in their RV including 24/7 A/C. I have 2 A/C units, a 14.5k btu Furrion roof mounted unit up front and a 12k btu 28.5Seer-2 mini-split heap pump in the bedroom. I have both a 12v and a 48v solar/battery system for redundancy and because I have some high amp 12v items like my slide motor, hydraulic jacks and my generator starter motor that draws 300+ amps. My 12v BMS can handle 330amps continuous with a 1,200a surge. I use my 12v system for all my organic 12v needs in my motorhome, though I do have a 1,000-watt inverter wired to provide limited mission critical back-up, like my fridge, if needed. We have a 12v 560ah (7.1kwh) lifepo-4 battery (8, 280ah prismatic cells in 2p,4s configuration) under the steps of our MH, charged by a 620w liftable array on the side, doubling as an awning for my bedroom window. My main 120v ac power comes from an all-in-one Sungold Power 5,000w 48v inverter/100a charge controller/charger. It's powered with a 320ah, 51.2v (16.4kwh)16s lifepo-4 battery that is charged by a 4,400w solar array on my roof. Ok, I had to go through that to get to the valuable info. My EG-4 28.5 mini split uses power at the average rate of .41kw/h. It obviously draws at a higher rate during the day than at night. During the day, even with moderate sun, we can run both our a/cs and charge our batteries at the same time. However, while we are asleep at night (8hrs) it typically draws between 1.5 - 1.8kwh. We also have a residential fridge that uses less than 0.2kwh during this time. During the evening hours, between when the sun goes down and we retire at midnight (say 5pm-12pm) we are using other appliances like our microware, the front A/C for an hour or so, our 55" HD TV, desktop computer, etc. so we typically draw from 2.5-3.3kwh during this time. This means we typically use from 4.2-5.3kwh out of our 16.4kwh battery (25-32%) nightly. This gives us enough reserve for 3+ days of bad weather before we must run our generator, as our 400voc solar array even produces 1.2-2kw of power in the rain, which is sufficient to charge our batteries as long as we're not running our front A/C (which draws about 1,500 watts when the compressor is running) - which we don't need to do unless it's sunny and hot out and we have 3,500+ watts coming out of our array. I know this is a little technical but should give someone thinking about sizing their solar/battery system some real-world numbers to work with. An RVer can typically run 2 rooftop A/C units using the 3,000w draw in your example, assuming a 100% duty cycle for the A/C units. Perhaps a 50-75% duty cycle is more realistic if 2 rooftop units are running. For reference, 2-3 12k btu mini splits consume about the same power (depending on their SEER rating) as one rooftop 13.5k btu A/C unit.

[@TheOldJarhead]

Great write up / comment! It takes a lot of power and thought to build a system like yours that will provide the needed power (which is more than most realize). Kudos! and thanks :D

[@junkerzn7312]

I started with 12V and 24V but these days I just go straight to 48V (aka 51.2V LiFePO4), even for small systems. And I try to do it with native 51.2V batteries rather than stringing lower-voltage batteries in series. There's just no reason to use lower voltages any more and the flexibility, headroom, efficiency, far thinner wiring, far lower amps, minuscule voltage drop, and almost no heat that you get from a 48V system is incredible. The cost is lower too, once you get into the bigger systems, due to the thinner cabling and lower-amperage charge controllers. Literally the only requirement for going 48V from the start is that the solar panel configuration generally needs to run 65VDC+. That is typically 3 x 100W panels in series or 2 x 200W panels in series or 2 x residential panels in series. Not hard to achieve! The only proviso is that someone retrofitting older equipment might need a lot of amps at 12V to run that older equipment, and that changes the game a bit since down-converting from 48V to 12V can be a challenge or a cost. So for retrofits there are still good arguments for going with 12V or 24V. Still, the sooner one switches, the fewer headaches there will be in the future. But there are also good arguments (in larger retrofit systems) to go straight to 48V and then down-buffer to a satellite 12.8V battery with a DC-DC charger and let that battery deal with the amps requirements. The one truism for solar + battery systems is that once you start, you will be wanting to expand it in later years and not just by a little. Even if you think you won't want to, you will. Its easy to get addicted to the improvement in quality-of-life that more power grants. -Matt

[@TheOldJarhead]

Great post and I agree 100%! Thanks!

[@bgzwlz5119]

Great video! I have been watching a lot of videos as I’m thinking about building out a van and I know very little about this stuff. Based on the info you have discussed, it is obvious that I need to go with 24V/48V. Obviously in a van, space is limited so that is a constraint and I think the primary consideration is the need to run AC off grid especially if you plan to explore the SW US during most of the year and/or you are traveling with a pet. Obviously, the cost/benefit analysis would be a factor because a 48V Victron system could be over $10,000. You need to balance that with the idea that if you are out of battery power, and it is 90 out, you might have to find a campground for the night for $75 to connect to shore power. I look forward to watching your other videos to see what else I can learn!

[@TheOldJarhead]

Thanks! I'd look at all options, including companies like Bateria, MorningStar, Midnight Solar etc as many are very good and less $$$ AC though is a hog so 48v is likely best. Look at BigBattery store for 48v batteries. American made so not cheap but I am impressed with their 24v mules.

[@TheOldJarhead]

The trouble with a van, as I see it, is room. You'll have to do the math on the AC unit and figure out how many watts it uses and for how long you'll run it (watt hours) and then get a battery bank to support it. My research says 6hrs for a typical RV AC unit would require about 8kwh so a system like the BigBattery Mustang would probably work: bigbattery.com/products/48v-2x-mustang-kit-rv-van/ but you'd then need at least 2kw of solar which would take 4 vans or a trailer to haul. Now, if you could stuff say 1500w of solar on the roof and hook up a generator and only run the AC 6 to 8 hrs a day and plan to use hook ups where possible, it's doable but expensive.

[@nolagirlhomestead]

Thx, this is not only right on time but educational! Of course ass-backward on math calculations... No can do 😅 Now is great time to consider 12v v. 24v system bc all elements already in place. Where do I grow from here? Next plan is mini-split. Thx again for good lesson today!

[@nolagirlhomestead]

BTW, adding 4th 100w panel to 100ah battery 12v system solved 1500w power issue. Hot pot, etc run like a charm!

[@TheOldJarhead]

Awesome

[@TheOldJarhead]

Thanks glad I can help!

[@bobbyemmons2754]

thanks for this video its helpful

[@TheOldJarhead]

Glad it was helpful!

[@evilss6064]

Great videos! I was going to buy a "fancy" extra battery for my solar power station but your videos have convinced me to add a few "regular" lifepo4 batteries instead. I'm new to this so im still learning. I have an oupes mega5 power station (5040wh) and I want to wire in a couple batteries into the solar input. I could really use some help deciding on what spec batteries to use. The solar input specs are as follows - 2100W Max, mppt: 18-140V, 15A Max. I was thinking I'd probably want to add between 5000-8000wh in total extra battery capacity. Would you use two or three 12v batteries? Two / three 24v batteries? What battery specs should i look for? Any help would be greatly appreciated! Thanks!!

[@TheOldJarhead]

Honestly, at that point why not build a DIY Solar setup? You could get the 5-8kwh of battery in48v LiFePo4's and an EG4 all in one inverter/charger/MPPT controller and would just need to wire it up to breakers/receptacles to have far far more power expandability than a power station for a lot less? If of course, you are set on using the PS I'd get 48v LiFePo'4 and wire two in series to get 96v (nominal - actual voltage would be 51.2x2=102.4vdc which is no longer low voltage FYI) be sure to fuse them! Two 100AH batteries would give you 10kwh but still only provide 1500watts to the PS.

[@evilss6064]

Thx so much for the reply! To answer about why not do the DIY solar setup- I have a small apartment. I cant mess with the breakers. And I have super limited room for solar panels. My main goal right now is to just add capacity to my main Oupes unit by adding batteries. Goal is to have enough battery to last for 2-3 days if I lost power. I can worry about charging once power is back. I do have two sets of the oupes folding solar panels that came with the unit (each one has 4 panels/ 240 watts for a total of 480 watts on paper... lol.. if I had both sets of panels opened up) And ive barely got enough room for both of them out on my 2nd floor porch. From what ive watched from you, adding batteries would be the easiest route. ...I think...

[@TheOldJarhead]

@evilss6064 Yes in that case two 48v batteries in series and fuse them 😉

[@sidlawrence4045]

Great content. Will these new batteries accept a full charge during freezing temperatures?

[@TheOldJarhead]

The BMS on them cuts them off at 32F I believe.

[@bgzwlz5119]

Is the battery self heating which might be important for mobile systems?

[@TheOldJarhead]

The one in the video is not. They are available though from CycleNBatt and others.

[@mh3558]

Just want to know is 48 volts dc 55volts when float charging is dangerous if touch with both wires during working?is gona shock you the same like 220ac

[@TheOldJarhead]

It depends on the battery type, but charge controllers are set to correct voltage for each system type. 48v could charge at over 57v. As for shocking, no. DC voltage is different than AC voltage but don't connect the wires!

[@dons5105]

Got a 2000 wtt solar generator with 4000 exspansion pack those run at 24 volt 12 100 wtt harbor freight panels generator 32 to 95 volt ×2 input bought 4 cheap 12.8 lithium ion phosphate batteries

[@TheOldJarhead]

Are you trying to power a small city with all that gear? Impressive!

[@dons5105]

Made 48 volt for larger gas tank turns out generator don't know the difference between pannels or 48volt now charges it works great

[@TheOldJarhead]

That's awesome to hear that the setup is working great now!

[@jalpa9642]

a 3 year Warranty...? That's nothing to write home about....!

[@TheOldJarhead]

I've seen plenty that don't have that. Some have much more but are also more expensive ;)

[@smavidsmampbell914]

Keto or Carnivore is the solution.

[@TheOldJarhead]

I tend to stick with natural as much as I can and do eat carbs, just complex carbs for the most part (ok I love sourdough bread so eat that too).

[@jamesalles139]

cut the carbs & vegetable oils

[@TheOldJarhead]

LOL well for the most part the only carbs I eat are natural whole grain carbs and I don't use oils in much except olive oil at times. But thanks! One can always improve their diet I suppose :)

[@jamesalles139]

@@TheOldJarhead Thanks for the reply. good, but it is deeper than that. Let me set the stage with a rhetorical (because it is loaded) question: _has the federal government ever lied to us?_ 'Whole grain' doesn't make it better. ditch the grains. "I Don't use oils" - it is hidden in every processed food product we consume, including bread - and even 'health' supplements. research 'industrially processed seed oils' Dr. Cate Shanahan or Dr. Chris Knobbe MD in particular. Eat meat and the fat that comes with it. Yes, we have been led to believe for generations that saturated fat is bad for our heart. NOT True. YT Dr. Ovadia - a board-certified Cardiac Surgeon. Dr. Eric Westman, Dr. Ben Bikman, Dr. Jason Fung, Dr. Paul Mason and many others, once you start looking. Understand that 'Nutritional Science' is a captured operation. The 'low-fat diet' was always bogus, never had solid science behind it. Wait until you discover what the Seventh Day Adventist Church has been doing (lobbying) - in the U.S., this is *un-constitutional,* IMHO. The goal is to improve your _metabolism._ thanks for the video.

[@TheOldJarhead]

One must eat carbs to survive. Fact is, we are omnivores and that means we eat meat, fat and carbs. The problem is people think only of simple sugars when they think 'carbs' and often tell you not to eat them while eating fruit (literally 'carbs') or quinoa etc. In order to get the needed (and yes, when we get older we realize just how true this is) dietary fiber every day, we must eat carbs. So, while I agree the government lies to us (every minute of every day) I don't agree that meat and fat is all we need. But realize, I'm one who doesn't eat processed food (that's right :D I cook!) and when I want bread, I make my own (usually sourdough but also often 100% whole grain/multi grain from flour I mill myself. I agree also about fat -- and I'm an advocate for natural. Natural fat, natural carbs, natural proteins :D Cheers!

[@jamesalles139]

@@TheOldJarhead No. We don't need to eat carbs. I am not saying you should want to eat just meat and fat. I do not do that. But fiber is not essential. There is no minimum dietary requirement (MDR) for carbohydrates. It is hard to convince anyone that they have been fooled. Stable blood Glucose is so critical that our body makes all we need. so, yeah, 100% fruit juice is not a health food. What I am saying is I lost 48 pounds in six months and kept it off for three years. I got my A1c down to 4.7 It is the seed oils + high blood glucose spikes and never getting insulin levels down causing heart disease (CVSD) to your health! 🖖

[@TheOldJarhead]

I dropped 60lbs in 2013 from a lifetime high of 287lbs to a more reasonable (for me) 227lbs in 6 months. How? Funny thing, I ate more complex carbs :) But that's not the entire story. I also exercised about an hour per day (often more but I also took days off here and there). As for fiber, we do need it. In order to keep things moving through our systems we need fiber (as well as hydration). When we're younger we can live without it but at my age (59) I've found no matter what I do, I MUST eat at least 20-25 grams with anything over 30 being ideal. As a former weightlifter I know the benefits of lots of protein as well as fat but again, dietary fiber is also important. Kudo's on your weight loss and keeping it off though! I'm currently about 50lbs heavy now, even though I'm not much heavier than I was when I was benching 350lbs, life has taken it's toll and now I need to continue to work DOWN to under 200lbs. Which will require lots of walking, mountain biking and indeed, watching my simple carbs :) Cheers!

[@Lordlindef]

1600 dollar is more then i payed for much much more better battery in 24volt battery. 11kw

[@Lordlindef]

Then I not have this leftovers batterys whit up to 5 6000 cyclus. I only have 35 000 to 45 000 cyclus. And made a little over what I did needed. In 2 year use have not used 1 single cyclus yett !!!!!!

[@Lordlindef]

Solar panels 320watt panels is 100 dollar for industry panels in ovc at 48volt. X 4 of them and never ever needed grid power again on my houseboat

[@TheOldJarhead]

Thank you for sharing your experience with solar panels! It's inspiring to see how they've made a positive impact on your lifestyle.

[@Lordlindef]

24 in smaller up to 10kw. 48 ofcourse is the thing thats take over all 12volt shaite. 10 bucks for 60 amp stepdown to 12 volt from 24 ore 48volt. So what is there to think of ??.? Many boats drive free and redused 85% of diesel fuel cost of an houseboat driving every week 😂

[@TheOldJarhead]

Who knew that voltage could be so entertaining? But seriously, those savings are no joke!