How Many Batteries For a 3000W Inverter?
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Are you wondering how many batteries are needed for a 3000W inverter? In this video, I will provide you with surprising insights, especially since many guides often get this wrong. I'll explore two examples: one with a lithium battery and another with a lead-acid battery, to demonstrate the ideal setup for your needs.
Many people use a 3000W inverter with just a 12V 100Ah battery, leading to early battery failure. I'll show why this happens and what you should do instead.
In this detailed guide, I'll cover:
- The importance of limiting current to 100Amps in an off-grid solar power system, and how it leads to reduced wiring costs, cheaper charge controllers, and higher efficiency.
- The calculation for a 3000W inverter, demonstrates why a 48V system is more efficient and cost-effective.
- The concept of C-rate for both lead-acid and lithium (LiFePO4) batteries, and why it's crucial for battery longevity and performance.
I'll also provide a practical example using lithium batteries, showing the calculations for a 48V system and why it's a superior choice. Plus, I'll repeat the process for lead-acid batteries, highlighting the differences in size, weight, and efficiency.
Remember, always fully charge your batteries before connecting them and respect the C-rate to ensure maximum lifespan.
For those interested in lithium batteries:
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thanks :)
😊
A professional off grid system never uses inverters such as those
😊😊😊
Your book was the 1st one I bought on the subject of Solar Power. I bought others, but kept referring back to yours for a simple clarification. The content and ease to follow on the various subjects is excellent. Many Thanks 🙏🏼
Thanks for getting the book and your kind words.
What is the name of the book please?
Good morning sir, thanks for your teaching but I want to learn more about solar panels installation please sir 🙏🙏🙏🙏
Very clearly explained with good graphics.
This is really helpful, thanks for explaining it. I am just about to DIY a solar and battery system !
Yea, I agree it's best to size the inverter to a margin above the expected peak load. The total battery capacity would be determined by the expected average load, as would a solar array(plus a region/sunlight-based margin) and battery chargers. Oversized inverters for a modest average expected power consumption has little effect, other than the idle current used to run the circuitry.
Very useful. I send it to my clients when dealing with what's needed in there RVs.
As a system builder I'll verify what he said is accurate, and must say one of very few I have seen to do it accurately. As to charge controllers another way to look at it, with a quality charge controller, at 12v best you can do is 750w, but at 48 same unit will do 3.5kw so you have more power available. a general rule, no matter the voltage the core wiring should be no less than 2 awg imo
Excellent explanation. ~Thank you
Thank you for the video and for the diagrams. I have been having trouble finding out and understanding this information, liked and subscribed!
Welcome aboard!
Thanks for going thru the math with us. I for one are very great full. Keep up the great work.
What about 12v?
thank you i was abit in the dark now i can see the light i am more confident to start purchasing my batteries and inverter
No problem! I will publish a video about a 1000W inverter soon. The same principles apply, and I tell why we size this way in that video.
@@cleversolarpower sorry to reply only now, I purchased a luxpower 48v 5kw and AND a 5kwa battery I forget the name, I had it installed and I AM very happy it's like a power station all on its own and bcos of the inverter I changed to gas where alot of power is needed so I don't fear the power going off anymore I feel protected
You actually sound like you know your subject ! Congratulations ! I have my doubts about many presenters on this platform as they often do not sound confident . Have a great year & life ! I will be buying your book , I bought Will Prowse book but when Amazon did not fulfill after payment was made, Will ignored me.......
Thank you, that means a lot. Have a great year too. People who buy my book can ask questions through email, so if you have any questions, feel free to ask.
I've seen some massive failures in the corporate world because people who sounded confident actually didn't know what they were talking about. Confidence and competence are different things.
Your information doesn't speak of Peukert's Curve, or how parallel batteries can feed very large inverters. For example, a 12v 100Ah SLA (or AGM, though temperature sensitive) can only survive a 50% mfg. discharge rate...but if you place 10 into a parallel circuit, now you have the equivalent of only 10% of the Current demand...so a 5-year SLA deep cycle battery can now yield 100A currents...simply by (in this case, 10-units) dividing the current by 10...thus, 10 12v 100Ah batteries can power a 4000 Pure Sine Wave Inverter just as one 12v battery could power a 400 watt (small) inverter...with approximately 4-hours before 50% of it's charge is reached. I KNOW, as I built such an array with an advanced 4000watt PSW Inverter and 10 such batteries (to power a remote cabin)...it can take a 100A load for 4-hours safely without deterioration of the batteries...and the built-in 90-amp charger is within recommended charge amps...7-hours, give-or-take, from a small generator, can bring the battery array back to 100%...and that's if you pull 100-Amps on that inverter (something a small cabin would NEVER do). In reality, it will work for 24-hours and charge for 5 (charging is automatic)...why does this matter? Because 10 12v 100Ah deep cycle SLA batteries are IN ARRAY, and one failing does not mean all fail simultaneously! So, instead of replacing a $1500 LiFePO4 failure is ridiculous, when 'old school' SLA batteries, good ones, cost $150 each, and tend to fail individually over a few months of time! It just makes more sense! ALWAYS use Peukert's Law (calculators can be found on-line) to determine size vs demand and recharge, and build an appropriate sized array! Draw it out first, plan your recharge method (in my case, the PSW inverter also has an automatic 8-second transfer switch which starts the charging generator, too)...Amazon, my friend, Amazon!
That’s the best video that I have ever understood on battery set up !
A really well structured video, Thank you for being ome of the very few people who introduce your topic by outlining what you intend to demonstrate. ✴✴✴✴✴✴✴✴✴✴
The 12V 100Ah Renogy AGM Battery you pictured far out paces your C-rate calc of 20A. It is rated at 30A with a 5 second rating of 100A! A couple of these tied to a 2000W inverter works wonderful in a typical RV.
It could deliver 1100A, but do that a few times and you will have a dead battery. Deep cycle gels or AGMs are not made for high current. Can they do it? Yes. Is it ideal? No.
No battery is good at high current. Geez, if makers would just get off of playing with the numbers trying to fool us to sell a battery. If you want high current, use super capacitors,@@cleversolarpower
the only time you would ever hit the battery with 1100AMPS would be with a big diesel engine lol @@cleversolarpower
thank you
Great information! Thanks for sharing.
You are oversimplifying a bit. Its not how big your inverter is but more what load you will put on it. Also you should have larger inverter than you need for starting motors unless you buy a coil based inverter. I'm running a 24v 960ah LiFePO4 system using a 3000 watt inverter. My daytime load (highest) is about 1000W. After a couple of days of cloudy skies, my batteries are empty. I could really use a larger battery however I don't have the solar capacity to support it (3.7kw) especially during the winter months.
Thanks for your feedback. You have to size for the inverter, not for the load you attach to it. Startup surge power is a whole other topic that I can make another video about. It's impossible to mention everything in a short video.
What do you run that uses 1000 watts,heck that could be an AC…? All I know is my 100ah doesn’t cut it so getting two 12v 230ah bats.
@@cleversolarpower - No, you do NOT have to size for the inverter. You have to know your loads and size the inverter to easily handle those, without pushing it too hard. Then you have to size your battery storage and your solar array. You keep acting like you have to go 100% all the time on all of these components, and that is most certainly not how any of this works, or should work.
@@2hotscottpromany things: microwaves, coffee machines, split A/Con, toaster, air fryer, electric jugs can all use over 1000W each.
@@2hotscottpro May I ask what you are looking for to buy. My batteries degenerated very fast (see my comments here) and I'm looking for a replacement. As far as i can see the best option is lifepo04. I’m looking at the brand Li Time.
Very excellent description indeed
Very good lesson in battery usage!
Very helpful thanks 👍
Per your comments @ 1:21 & @ 1:49, it would seem a Lead Acid Battery Pack should also be given that "25% Buffer", meaning a 400 Ah x 48V pack, or 4S4P Pack is really safer! But, most Lead Acid Batteries aren't rated at "0.2C" they are rated at a "20 Hour Discharge Rate". A 0.2C is actually a 5 Hour Discharge Rate (5 x 0.2 = 1.0). So a 20 Hour Rate, is 0.05C (20 x 0.05 = 1.00) You can find "Some" Lead Acid Batteries, rated on a 10 Hour Discharge Rate, as well, if you get the Higher Priced And more Exotic ones. However, this still doesn't count that Lead Acid Batteries shouldn't be discharged to "Dead" or "100%", but in normal use, should never be drawn down below "50%" of Rated Capacity! (If you want any meaningful Lifespan from them!) 😲
max life a bank never should go below 25%, but between cost and size the standard for most is 50% depth of discharge, so basically once you calculate needed run time, add a safety factor, you either multiply it by 2 (Cost/life span ratio most go with) or by 3 best life but higher cost. But he was correct in absolute bare minimum to operate an inverter with out destroying the batteries (And possibly inverter) is a 100AH battery, but be pretty useless functionally due to next to no run time.
Great info, thanks for sharing buddy!
I like how I can go back over the information and get a little better understanding, I think calculating sun hours and number of panels will tell me what I can afford i.e what size will my offgrid setup cost which in turn will tell me what I can run, cheers mate
Glad it was helpful 🙂
Thank you so much for sharing 😊
Good information. I would add the DOD factor to point out the differences in the chemistry's
Good question. But I usually use money for an inverter and not barter in batteries for an inverter.. But whatever works for you, money or trade.
"Limit current to 100 Amps..." This is why I shall do a 36V system. And your explanation of the C-Rates of batteries explains why those Telephone Central Office Backup Banks I installed were so huge. I'm a retired electrician, and, frankly, managed to miss that day in class.
Maybe you can help. I use electrodacus system, but it's 24v. Is there a better system on the market? I still don't understand the rationale for using 100A system. My batteries are prismatic cells and they come in 280Ah configuration.
Limit to 100Amps is not a rule set in stone, but i like to use it to size systems for costs reasons.
@@gushardy4421 We're referring to the LiFePO4 Batteries, and the Battery Management System (BMS) they have inside them. The Battery may very well have a rating of 280 Amp Hours (AH), but a Battery management System that only allows a charge or discharge rate of 100 Amps. In a 12 Volt system, this limits you to a 1,000 Watt load. If you use a 24 Volt system, you can double that to 2.000 Watts. P = I * E. Power (In Watts) equals Volts times Amps. We doubled the voltage, we doubled the watts available. And don't need to get bigger wires for the moar Amps. You mileage may very, and your 280 AH Battery may well have a 280 Amp BMS. And it may not. So, with 2 Batteries as a 24 Volt system. IF they have 100 Watt BMS's, you're capped at about 2,000 Watts of load. If, however, they have 280 Amp ones, 280A X 24 V = 6,720. For safety reasons, always set things up so you only pull 80% of the possible Maximum. So, 5,000 Watt, rounding down to a nice even number.
@@cleversolarpower 100 Amp cable is SO much cheaper than 200 Amp!
New to your channel, I'm trying to apply your formulas to my case but I'm having trouble using the C rate of my AGM Renogy 200A/H battery, it seems that it's 0 05C, is that correct? My setup is basic 400W solar with a 30A PWM charge controller and a 2000W inverter. The main use is to keep the fridge/freezer (300-400W) powered by the inverter while we tow the trailer, therefore without using the propane power. Do you see any issue with this installation? All comments and responses are welcome Cheers Phil
Thank you so much!
Great info for longer-term setups. For short term, I use a 12v 100AH battery connected to a 3000 watt inverter. My total amp draw is about 12 amps per hour if I opt to run everything I need at the same time. This carry's the load for about 6 hours. I have a second battery that I charge on a propane generator while the other one is carrying the load, then switch them out. It takes about 1.5 hours to charge the battery, and I get about 14 hours of run-time on the generator for a 20# tank, which means I could get about 48 hours of power to the things I need. (TV/Internet/fridge/freezer/window AC unit/ portable heater/etc as each is needed) - I normally do not run everything 100% of the time, for example the window AC unit draws about 800 watts/5 amps by itself, so I tend to only run that intermittently, and hunker down in just one room with it running about 20 minutes per hour on average. - Same for a space heater if it is cold, though it has an even higher current draw)
Don't forget that a 3kw inverter will consume about 30-50w just idling. That's 720wh-1200wh daily. You can use a small but efficient victron inverter for small loads and turn off your 3kw inverter when you don't need it.
How do I find how many amps I'm using? My system doesn't seem to have that capability...
@@LotsaThingsNstuff - There is normally a label on the items that posts the amp draw (or at least the watts, and you can then calculate the amps - but always account for the initial surge, which is normally higher (briefly) than the stated running watts or amp draw)
@@LotsaThingsNstuff A=W/V or Amps=Watts/Volts Ex: in a 12v system 1500 Watts / 12 Volts = 125amps
Everything is based on usage. Your not going to run everything at the same time at least I hope your not going to . I use 12v backup lighting and run a 2000w inverter for fig and freezer. I use 6 lead deep cycle batteries 780ah each backed up with 800ah solar and one 200ah wind turbine. I can go for months without needing to charge with normal means . This is a backup only system not living off of it
Thanks for your nice assessment.
I use 12v lighting in every room and 2000w inverter for frig and freezer. Supply power is 800w=8 amps solar 200w=2amps wind feading 6 lead deep cycle 780ah batteries. Now given we dont run all the lights and kids dont leave frig door open lol i can run for months without needing charged from normal means . I set my system up for backup only (just incase) but i know im good to go . Off grid if need be
Something you could talk about is using busbars like in your diagram. I bought some aluminum 1/8 x 3/4 stock and cut it down to 6" with two holes drilled in it for battery connections on my lead acid setup. Seemed to work good. I want to go with copper for my lithium hookup but no one talks about it and it seems everyone expects us to make interconnect cables. They also talk about using the same size for all cables and it seems to me interconnect battery cables for a 48 volt doesn't need to be as large as the wires going to the inverter. Large cables to the busbars where all the 48 volt batteries connect to. Very good video, thanks and I liked it.
Good idea, I will put it on the list.
what about 3000 watt inverter, 12volt 3x 300ah lifepo4 batteries and 800 w solar panels? how do I remedy?
Whats the problem?
Most modern inverters will draw from the solar power before the battery so when the sun is out the current can be much higher, but I agree with the load you have calculated for batteries.
The current is not higher when the sun is out. These are the inverter cables, not the cables from the charge controller to busbar/batteries.
Yes the current to the load can be higher and not effect the battery load so you can stay within the battery specifications of 1c or whatever you have without effecting the life of the battery some inverters don't even need a battery. @@cleversolarpower
Great Info, much appreciated. The 80 amp fuse conversation confused me? May I please ask if this set up(4 x 12v 100ah) works for a 4000 W inverter. I ask because of the fuse situation and needing more than the 80 amp fuse you discussed?
I don't understand your question. Repeat the calculation for a 4000w inverter and apply the voltages of your battery. Then check if it's ok compared with the advice given in the video.
Thanks for information long time ⌛️ asking from many people my mind on settle ❤
I have a 20w solar panel, 30a charge controller,12v 7ah battery and a 200w inverter. Is using the 7ah battery with the 200w inverter to charge my 33watt phone ideal
That was Great. I do like the product link and explainations.
Glad you like it David. Feel free to suggest video ideas 💡
Thank you for the video. How about a practical example in the end? Like with the 48v 100amp hour, how many hours can I run a 15 amp window ac unit and how long to recharge with a generator like off grid or during a power failure scenario. I appreciate the math, but I need to know run times and re-charge for better context.
Thank you!!!!
Hello mate thanks for the great video you've gained a sub , this is my first time using solar. Im about to use a 12v inverter (3000w) with 2 12v 115ah lead acid batteries and a 30A solar controller. my concern is the amperage however do you think this can work ? Thankyou in advance
If you’re in the UK go to 12 volt planet for advice. Personally I wouldn’t use anything other than Victron gear. As for your proposed configuration, even if you rigged your batteries up to give 24 volts to reduce the current (volts x amps = watts), you’re at 125 AMPs, that is a huge current and therefore fire risk + it would destroy your batteries. As a side note, my 500 watt Victron is rated for 900 watts for short peak loads. I initially bought a cheap Chinese one which was dangerous rubbish. From his calcs, the theoretical max for your batteries would be in the 500 to 1000 watt range depending on how you set it up. The 30 watt solar controller sounds OK though. I have no association with Victron, but the other great feature is all their devices have blue tooth and a great app so you can monitor and control your set up through your phone. Hope this helps
I have 2x 100AH Lithium RENOGY and a choice of a RENOGY 2000W or 3000W inverter. I think I’ll go with the 2000W for this year
200Ah LiFePo4 with 2500W Inverter, maximum need for Induction hob and Air Fryer is around 1500W, Microwave and Coffee maker uses less, so have used this combo successfully. Battery also has 200A BMS and cables are thick and 60cm long. So there is a way, but I admit that you are perfectly right!
If the cables are thick enough then it will work for sure. You will pull 208A so you indeed need a 200A BMS. However, it would have been better sized if your system was 24V, 48V -> less current. But it will work 😄
Have not installed yet I purchased a 3000 W inverter that will handle a 6000 W. I don’t recall the amount of time but it’s a start of it for starting large motors and things load.
Then you are better off with a low frequency inverter for inductive loads.
I installed a 3KW pure sine wave inverter together with six 110 AH 12 volt leisure batteries wired in parallel on our boat six years ago. I didn't do any calculations. It was just my gut feeling of what was needed. We have a 230V fridge, a 230V 26" LCD TV, a 230V microwave, a 2KW 230V Electric kettle, a 17 inch Laptop PC run with a 230V charger and can go away from the mooring for a week at a time and run those things with no issue. We do have a diesel powered, 12 KVA generator installed too but rarely use it.
Yes, it will work.
Batteries:Why not in series?
@@afzaalkhan.m My inverter requires a 12v supply. Running six 12v batteries in series would produce an output of 72V. If you look at the diagram at 5.29 in the video above, you can see three lines of batteries. The horizontal lines are in series giving 48v and then the three lines are connected in parallel vertically to give 300 Ah.
that would be 72v @110AH per 20hrsseries instead of 12v @ 660AH per 20 hrs. parallel. He could have also tried 36v@220AH per 20hr load with three sets of 12v batteries in series / parallel.@@afzaalkhan.m
I use 3 x100 A.H. Lead Acid batteries for a 12 Volt 3000 Watt sine wave inverter..it runs an 800watt Inverter with ease.
Wonderful video with everything broken down. Thank you, a question, though. Are the calculations for the Lead-Acid battery the same for AGM batteries?
Thanks. No, lead acid has a c-rate of 0.2C while lithium has a c-rate of 0.5 or 1C depending on the BMS.
@@cleversolarpower with all due respect, the question was regarding an AGM (Absorbant Glass Mat) battery. (I am looking for the answer to the same question)
You get the same reduction in individual current draw if you connect the batteries in parallel. Typical 12V LiFePO4 battery is rated to 100amps continuous (as per your examples). a 3000W inverter running at 90% efficiency or better (typical) requires around 3300W of input. 3300W at 12V = 275Amps required (Watts = Amps x Volts). 12V 100Amp battery: 275Amps/100Amps = 2.75 - rounded up you will need at least 3 batteries. Therefore: Running 3 x 12V batteries in Parallel gives 12V 300amps continuous (with a power capacity of 3600W (12x300)). Provided batteries are of the same type (they should be), the current draw on each battery should be evenly distributed. at 3300 Watts or 275Amps, each battery will use around 92 amps. So, 3000W at 12V only requires 3 batteries (in Parallel). To achieve 3000W at 48 Volts requires a minimum of 4 batteries (in Series). It's all about sizing your system correctly. Trying to run a loaded 3000W inverter on a single 12V battery delivering 100Amps continuous, of course you're going to kill it prematurely. The key advantage to running in Series (to 24 or 48 Volts) is it keeps the overall Amps of the whole system lower, meaning you can use thinner wires and have lower resistance/less voltage drop (not a concern at distances of less than 6m). 48 Volt systems are typically used for homes with 5KW -12kW inverters (104Amps there @5kW without losses on only 4 batteries...) 12 Volt (and 24 Volt) systems are typically used for Caravans, Boats and RV's.
The only time I’ve seen a situation where we had to select battery bank size based on the inverter is when using Simpliphi Li batteries. They can only discharge so many amps (it’s very low) and if the inverter was to run a large load the batteries wouldn’t be able to keep up and there would be serious issues. We had to have 3 of these 48V batteries, not for the capacity in Ah or Wh but because of the amp draw that could happen. Ridiculous
I did an experiment trying to make a system that was the cheapest possible that could run a 5000 BTU air conditioner. The single 12-volt 100 amp hour flooded lead acid battery it had lasted around 3 years. The cheap modified sine wave 1500 watt power inverter lasted almost that long. The system was also used to run a 500 watt heater in the winter. The goal was to use the power when it was available and not store it. The main drawback was that it would shut down on cloudy days often. Would be nice if there was an easy way of dialing in a cutoff voltage and having automatic restart with cheap inverters. Btw, I do only buy pure sine wave inverters now. They more than make up for the increased cost by how much longer they last, not to mention the increased efficiency,... I've also moved up to sealed lead acid batteries.😂 My favorites are the 6 volt 200 amp hour Mighty Max sealed lead acid batteries. If you don't run them down too far they're supposed to last 10 years, completely maintenance free. You have to use 2 of course for a 12 volt system. You can get a pair for around $439 delivered from eBay. Seems to be the best bang for the buck concerning batteries I can find. They'll even build up your muscles, weighing around 64 lb each.😊
Next upgrade would be lithium. Checkout my video comparing the two. You can get a 12v 100ah lithium for $300 now from a good company.
That’s bang for the buck
Thankyou 🦘
The best feature of lithium batteries is how they deliver most of their current above 12.8 volts. Inverters love 13.3 volts
Great video, lots of interesting facts. Dont forget to verify the code in Your area, lots of nations do not allow non-electricians to work on more than 12 volt.!!! - DC can kill !!! To determine the number of batteries needed to support a 3000-watt inverter for at least one hour at full capacity, we'll need to calculate the total energy required and consider the discharge rate and capacity of the batteries. Calculate Energy Required: Power (W) = Voltage (V) × Current (A) For a 3000-watt inverter, assuming a 12-volt system (common for LiFePO4): Current (A) = Power (W) / Voltage (V) = 3000 W / 12 V = 250 A Capacity Needed: If you want it to run for 1 hour at full capacity: Capacity (Ah) = Current (A) × Time (hours) = 250 A × 1 hour = 250 Ah Number of Batteries: Considering the BMS's limit of 100 amps, and assuming you're using batteries of 100 Ah each, you'll need to connect them in parallel to distribute the load: Number of Batteries = Total Capacity Needed / Individual Battery Capacity Number of Batteries = 250 Ah / 100 Ah per battery = 2.5 Since you can't have a fraction of a battery, round up to ensure you have enough capacity: 3 batteries Wire Size: For wire sizing, you'll want to consider both the current and the length of the wire to minimize voltage drop and heat. Since the BMS can handle up to 100 amps, choose a wire gauge capable of handling at least 100 amps. Additionally, consider the length of the wire and refer to a wire gauge chart that provides the recommended wire size based on amps and distance. The American Wire Gauge (AWG) standards can guide you. A 100-amp load might require at least 4 AWG wire, but if the distance between the inverter and the batteries is significant, you might need a thicker wire (lower AWG number) to reduce resistance and voltage drop. Always consult local electrical codes and standards for proper wire sizing and safety measures. Additionally, remember to fuse or use circuit breakers appropriately to protect your system from overcurrent situations.
I would also increase the voltage to save on other components.
Excellent
Just put you book in the cart. I have no knowledge of these systems and setups. I have a question that may be a tall order . Can I get a shopping list to power a 220 volt well pump ? To keep only my water flowing. The house is covered with a DP and added battery, now to get the water covered. Thank you.😊
Thanks for getting the book! Take a look at my video about 'solar without battery' for inspiration for powering the pump with float switches.
Great explanation. I'm saving this video to my favorites list.
Awesome, thank you!
I have a 12v 3500 w inverter what would you recommend for 24 v battery ( 12v/200ah) configuration , I also plan to use a 60a charge controller ! Would that be safe ?
You cannot use a 24v battery with a 12v inverter.
your inverter sets the system voltage, so you'd be connecting batteries in parallel for 12V at 400Ah, 200ah usable for best battery life (50% depth of discharge). 12v*200 = 2.4KwH of usable energy. 60amp charge controller * 12V = 720w max solar energy can pass through it 2.4Kw * 1.35(Conversion loss from lead acid battery) = 3,240watts of energy needed to recharge from 50% usage of battery. 3,240watts / 720 = 4.5h of solid sun time needed. Doable in most parts of the world, but cutting things very close. At 2,400watts usable energy you divide that by your load in watts to give you run time
Very good explanation i have 5000 watts inverter how many batteries do i need and like wise solar panels and controller Gines
Hi Gines, You can repeat the calculations for your 5000W inverter.
Quick question wouldn't it be helpful to hook up a trickle charger to keep from running down the batteries
Yes, always useful if you leave the batteries unattended for a longer period of time, especially lead-acid.
Good info.
Thanks!
so I have 3x 105 AH battery bank. for 315 AH - planning a 2000 watt renogy invertor with 1/0 cable and a 250 AMP fuse. SOund good? we will almost never use appliances over 1k watts. we wanted the extra just in case. does this sound OK? 12v AGMS
Sounds logical, my renogy 2000watt does great I'm in 3 100 ah lithiums
I just published a guide on calculating wires and fuses. Even if your inverter can draw 2,000W, you need to size for a 2000W power draw.
Small battery bank will have very short run times, AGM's are easy to kill very sensitive to charge voltages. The fuse is sized to protect the wire, not your devices, but with single aut you're fine with that fuse.
i agree im building a micro ecamper for my electric bike and im using 48 volts system made from 50 amp draw molie cells so it will power the bike and all the camper electrics and recharge off solar when camping
im usinmg 48volt for only 1500watt system though
If you have a 50A BMS, then it will work 👍 good sizing btw.
its getting quite complicated because the camper also has 2 hub motos and 2 controllers so it powers itself and doesnt put stress on the tow linkage,this way i can tow alot more weight while only feeling like a lighter weight,
i might be better off looking at keeping the systems separate but its hard as it all charges off the 4 300 watt panels
Im a bit confused i have a 2500watt mig welder max 90amp. Thinking about fitting a 3000watt inverter in my garage what battery would i need to run the above thanks.
What's the absolute top surge amperage when you create your spark, that could b well above 3k. Then you need to decide whether you want 48/24/12V batteries. Then you need to decide what chemistry you will use, lifepo4, lead acid, gel etc. Then you need to figure out your usage over time in order to size your array. There are many steps to take on your journey.
I always use my generator for welding. I'm running a 24v/3000w system. Welding impossible.
Hi this is from my house it'll be recharged for my truck my truck has an inverter and I'd be plugging in a 50 amp battery charger into my truck I'd like to buy two 200 amp lithium batteries for a total of 400 amps in a 3000 watt inverter to run my refrigerators at what consider a 2000 watt inverter. Pure sine . I will only be charging my refrigerator for power outages and basically I would be putting 5 amps back into the batteries as they're being discharged on the recharge side. What do you think
Hi, can you please help in my project, I have a mppt controller AUTO 12,24 & 48V Wind 8 KW & Solar 5 KW and inverter 24V 6 KW - 12KW for this Project I think to use the LiFePO4 8x3.2V 310Ah. If I have mistakes please correct me.
what is the system voltage as this will determine every thing from wire size to needed bank needed if 48v 8 cells will not do it, you need bare minimum of 16 cells I personally like a slightly higher voltage and calculated 18 cells for my self (ATM I have 32KwH lithium Polymer)
@steffenBoserup thanks for taking the time to write it out for us.
The 80A fuse you recommended, is that the AC fuse for the Inverrer? If yes, don’t you think that would be too much, especially, with a lead acid battery setup, considering that you would only be pulling and also charging at a current just around 20% of the battery capacity rating, per hour?
It's the DC fuse.
where does the 0.2c discharge rate come from? I have never seen that specified by a manufacturer. I have seen a 0.1c charge rate for lead-acid batteries, which makes charging them decidedly slower.
It's specified in the datasheet of batteries. The capacity is mentioned in ah at a 20 hour rate. This is 0.2C. The manufacturer would list the capacitiy of their batteries at a 20 hour discharge rate. It's also known as C20. Check my video about C-rate.
@@cleversolarpower Yes, of course - the marketing term. They advertise 100AH at the 20 hour rate - *0.05C, actually.* That is only a measly 5 Amperes (continuous). However, it is not necessary to be this conservative. Otherwise, no one would be able to start their car in the morning. What needs to be looked at is a series of curves. And decisions made on the trade off between capacity performance and the number of charge cycles over an acceptable lifetime. If you discharge continuously at 100 Amps, you might get something like 70AH out of it, in much less than an hour. (Mfg. vary) but you wouldn't want to market it this way. And sure, you will get longer run time and longer life if you take it easy on the current demand. But most real-life loads (except heating) have an intermittent duty cycle. So lets look at my conservative design. 3 pieces of 12v 105AH AGM batteries in parallel. I want to use 50% of that capacity, or 157 AH; or 1,800 Watt-hours (nominally). And I like the idea of limiting to 0.5C for discharge and 0.1C for charging. And that gives me slightly over 150 Amps. Well, the inverter I chose is 2000 Watts, which is 167 amps at full capacity. I like to de-rate the load to 80% which would draw about 133 Amps. I have no problem doing that 0.42C continuously down to 50% State of Charge (SoC), which should last for about an hour. Then of course making the battery happy by getting it fully charged again. I use a 30 Amp smart charger for this rig. Also, with lead-acid chemistry, I have the headroom to support the full rated 4,000 watt motor starting capacity (inrush) current of 333 Amperes. Thanks for the videos! Cheers!
Thank you I’ve got 280AH 3.2v batteries x 8 = 25.6v my inverter is 3000W 24v although I have a 5KVA Inverter but it’s 230v x 1 and the Chinese electrical grid ground also has a positive current Recommended within the inverter you can disconnect the power lead going to the negative ground cable but I haven’t seen that video how to do so to salvage my 5 kW inverter is in the American grid you could take the neutral and the L one each of 115 V this one phase 115v to my breaker box I have no 220v !
Home off grid style back up. 4 100 amp 12v lifepo4 in Parallel, 3000 pure swine Renergy, 250 amp max peak , with 1 kw panels , for home backup, manual Generator switch, non grid ,
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Welcome aboard!
Awesome video, very well explained. I wonder, could you also make a video to compare lithium batteries to the more recent sodium versions?
Great idea, thank you for the suggestion.
I had two 48 volt *_AQUION SALTWATER BATTERIES and the SUCKED!!!_*
@@onmyworkbench7000 Can you share some more details? There is however a difference between sodium batteries and saltwater batteries.
@@PhG1961 It was Aquion Energy and I had a pair of their 48 volt batteries then a few months after I bought them they filed for Chapter 1. It's my understanding that they have now emerged from Chapter 11 but I don't know any more than that. The Issue with the batteries was that they only had 2.2 kWhr capacity with a peak power 1 kW each. One of the ones that I had died so I replaced them with 4 48 volt EG4-LL Lithium Iron Phosphate batteries.
What was wrong with the Aquion batteries? Our supplier was selling them several years ago then the company went into receivership. A company from Germany bought them for 9million. Aquion had spent $150M or so on R&D. They were 50Ah at 48V so 2400Wh. Not a lot of capacity but that’s one battery. They’re very safe and have good cycle life. Can’t let them freeze though. Also tipping them over voids the warranty.
We have an alternator of 12v in a van vehicule, how can we install a system working at 24V or even 48V in order to be below 100A when requering high power, such as 3000 W and higher. I do not have clear how to charge the batteries using the van alternator. Many thanks
If you want to charge with your alternator I recommend 24v systems. I haven't found any DC to DC charger that is 12-48V. I have a video about different voltage systems in a few days. You would have to sacrifice some efficiency using higher than 100A, it will be more expensive, but in an RV this is what I recommend. Recently I installed a 24v 280ah battery in an RV.
@@cleversolarpower Many thanks for your prompt answer, I fully agree. Can you recommend any buck boost to increase de voltage from 12v to 24v in a RV? I am facing some problems to find one with enough power at a reasonable price.
to me there is no reason to run a 24v or 48v on a rv at all stay 12v and just get a big battery bank at 12v then you can get a 200-370 amp high output alternator if needed and can get a few solar panels on your roof in most cases on a RV you have all short cable runs and very small space for solar panels so there is not need to to go with a higher voltage system at all and they make lots of 3000 watt 12V inverters for this reason as that all you would ever need in a RV also can charge very fast with the engine running and run everything at full load no problem
I recently installed a 12v battery 100ah tied w a 12v lead acid 50Ah in parallel. I have two 200 W panels on the roof for 400W total. Using a BougeRV controller rated 600 watts max solar and 40 amps. The only thing I’ll be running on that is the new Starlink Gen 3 satellite, which pulls approximately 85 to 100W. Along with that, a mini movie projector that pulls 80W. I should be good, right?
To keep the lead-acid battery happy you should not discharge lower than 50%. Since it's in parallel with a lithium battery, this will become the same. So you can only draw 50% of the lithium battery as well. You can draw 25Ah+50Ah=75Ah from your two batteries. If you only had the lithium battery, you can draw 100Ah. total energy for the lithium battery is 1280Wh. 100W starlink*24h=2400Wh. -> Your battery is not big enough to support the load for one day.
Well explained, can you send these formulas?
Thank you for the clear video, I agree with its content but feel it slightly ignores a key dimension to this issue: it is mostly centred around the idea of running an inverter from a single battery only. In that case obviously higher voltages will fare better than lower voltages because they will require less current. But isn't it the case that you can supply the necessary input to the inverter within the relevant "C" constraints of your battery chemistry by adding more batteries in parallel. I am happily running a 3000W inverter using a set of six 24V (110AH) LiFePO4 batteries in my off grid cabin - at 3000W the total current is 125A but each battery is only discharging at a sixth of this because they share (equally, according to the bluetooth instrumentation they display) in the supply of that current. Did I miss something?
You are completely right. Having a larger battery is the best solution. Just like you did. I thought I made that point clear in the video 😅
@@cleversolarpowerSorry! I went through it all again and saw you did make that point in the lead acid section.
I recently bought a 12V/200amp battery with a 200A BMS, and a renogy 3000W inverter with a 60a charge controller, to build a light system for camping in summer, would this be a good kit? any suggestions?
Do you really need a 3000w inverter? Bigger isn't always better. Your C rate is ok, but your cables need to be big. If you had a 24v system you could have smaller cables and a 30 amp charge controller.
Thx for your reply, forgot to mention i have 1/0 AWG cables for that connection.@@cleversolarpower
@@mlora929 inverter is a bit big for your battery but still will work just fine
You won't be hooking up that 12v 3000w inverter to a 48v system though. Wouldn't 12v 800ah be sufficient to run the 12v 3000w inverter without killing the batteries?
Your formulas are correct... no doubt at all. The problem is, instead you did, the approach. It must be done deal with in terms of energy consumption in 24h. You're assuming a costant load of 3000VA... this is not a real case. To me the right figure should be starting at 0 o'clock with battery full charged.. recharge with solar panels the consumption will be regular as for familiar habit, with peak load, no load or minimum load. The important is total PV energy IN must be equal to the total consumption OUT. At the end of the day the battery is almost 100% recharged.
I think you misunderstood the subject. This is not about sizing a solar system. I have made a separate video about that. This video is about what kind of battery you need to support a working 3kw inverter. It doesn't consume 3kw all day.
@@cleversolarpower listen to me... a lead acid 100AH battery for motor vehicle withstand 850A for few seconds... this occur when you start a diesel engine. The same battery can easily withstand 3kw inverters for few minutes.... Maybe I have made some mistake about the topic but anyway speaking about solar plant with you @cleversolarpower (the nickname you've chosen) is natural and never out of the topic.
@@joblack3991 Batteries that start your car are not constructed the same way as deep-cycle lead acid batteries. The plates are thicker to deliver the high current. Deep cycle batteries are made to deliver current for a long time (thinner plates). They can withstand higher current, but that doesn't mean its good for the battery.
There is an error in the video. Lithium-ion has discharge C-rate = 1C, but charge C-rate = 0.5C (video mentioned both being 1C) Also for those interested, LiFePO4 batteries have discharge C-rate = 10C and charge C-rate = 1C
Batteries can charge at 1C nowadays.
So, to simplify, you recommend a lithium battery should be sized to have sufficient capacity (in Watt hrs) to run at the inverter's full power for 1 hour, or 5 hours for lead acid batteries.
A question I used to ask electrical design students was if I start a 100kw generator with a 208/120v 3 ph 4W system, how many amps does it put out. In your case, if I have a 5000 w inverter and turn it on, how many amps at 120 volts is it putting out?
0 Amps because there are no loads. I feel like this is a trick question 😄
2 12v 200 AH in parallel. 2000w inverter. Most it can draw at once is 17 amps. That is rare though. No problems so far.
A 12v 100a battery usually has a 100a output or 1280 watt. You would need 3 batteries in parallel to satisfy max inverter output. But you should also consider max output from your dc panel. Add both numbers together dnd you might find that 4 batteries in parallel are the safe option. Just be aware of the specs of the battery. Not all are rated at 100amp discharge. In particular larger batteries may be 100amp discharge but have a greater capacity, so going by capacity alone won’t work. You would still need 4 batteries if you yse 200ah batteries that only have a 100amp discharge rate. And don’t forget about 20% marking for surge.
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Which 3000w output inverter to buy so that I can connect it to a 12kWh 48V 230ah LifePo4 battery ( I charge it with panels via Victron 150/35), and I will be able to charge household appliances with it, such as a washing machine, dishwasher, oven, ...
I recommend taking a look at the victron multiplus. I think you need the 5kW version or even the 8kW version to power your loads.
Which is better and more durable between Transformerlees inverter and Transformer inverter? Which inverter will you advise?
Transformer inverter is more durable. It can also handle surge loads better than high frequency inverters. Transformer inverters are more expensive but are preferred.
@@cleversolarpower Thank you!
for maximum battery life, i suggest a max amp of 10A per battery. Most people did got this part wrong and destroy battery within a year. battery capacity should be considered on the area you live in and the amount of sun you have. If you are living in sunny places close to the equator, its enough to have a 20AH battery capacity per battery and increase the number of battery to decrease the amp output per battery. this is because the amount of sunlight recieve is around 8 hrs a day with very little variation. rather then counting the maximum capacity of the battery, it is more aplicable to go for sustainability by decreasing the amp output from battery especially if using acid lead
You seem to be referring to a load calculation. You can check my video about it on my channel.
@@cleversolarpower6:09
Please, how can i get your book, I'm watching from Nigeria
You can get it on my website in PDF form. Thanks.
Thanks so much, I ordered the free diagrams. But one feedback: for some reason this video is blocked for saving to my solar power playlist for future replays and reference. Why have you blocked this option? Usually that option is only blocked for videos not suitable for children.
Thanks! I tried it and it seems to work fine for me. There is no option to prevent this from being possible.
I just bought the power queen 12.8v 300AH battery and their 2000W inverter, do I need the 3000 W inverter? Or is 2K ok?
It depends on what your load is. If your load is larger than 2kW, then get the 3kW. If not, best to go as low as possible.
I use deep cycle marine batteries and I have a way to get more.. you can't have too many batteries in parallel it just takes longer to charge
Thanks for the clear explanation. I have a 24v battery bank 2 x 230 ah (460x0.2=92) with a 2500 inverter (2500/24=104). My batteries degraded in a very short time span of 2 years. I am doing my best to learn from my mistakes. My first thought was that I discharged the batteries too much too often. The only guard for discharging too much is the inverter low voltage shutdown. But after your video i do not think that only the above was/is the case but i also sometimes discharged my batteries too fast. I am very curious what you think about this case. A company nearby claims that they can regenerate lead acid batteries in some cases. I will try that first, testing is free of charge. I’m also looking into lifep04 batteries for plan b.
Do you have two 12v 230ah batteries in series? That's 24v at 230ah. You should have only discharged lead acid to 50%.
Ordinary auto, ie. Starter motor battery will degrade quickly, Deep cycle batteries are needed for solar if using lead acid. Hope this helps.
@@cleversolarpower Yes, in serie to make a 24v system. I know now lead acid on 100% is 12,7/24.4 volts and on 50% it's on 12.1/24.2 volts. I discharged them sometimes to 23 volts and not often but sometimes to 22 volts and in winter when there is not so much sun i didn’t take care of my batteries well enough i think. My thinking was, the batteries are big (AH wise) and my victron charge controller would take care of the rest. What I don't understand is that in my victron app often in the summer the state of charge was 28 volts, how does this work?
@@Peranaworthal Thanks, do you mean that the lead acid batteries never can be deep cycle batteries? Only AGM or Lifepo04 batteries are could for that use?
He means deep-cycle lead-acid batteries, like marine/boat type. Starter batteries meant for cars will degrade fast when used in solar. @@moziani9093
if you live in the 1980's and are using lead based batteries, simpler math is take the wattage, ie 3000w, divide by 10 so 300w, add half as much on again so 450w, change the w to Ah, boom theres your minimum pack size. as they are normally sold in 100ah, so buy 5 of them for 500ah
That's one way 😄
I have 4 100ah 24v batteries and a 3000w inverter but, i cant seem to run off my battery bank for more than a few hours, im not sure what the issue is, im only pulling like 4-500 watts at most
The idle consumption of a 3000w inverter is about 30w x 24h= 720wh. Have you taken that into account? 500watts for how many hours? You can check my video about load calculation for more information.
Please can 1200 watts on lights. small power tools. small air conditioners. small portable heater. television. small refrigerator. small microwave. small to medium-sized fans. If yes please which type of battery should i use 12v 100Ah
I recommend checking my video about sizing an off-grid solar system. This will help you answer your questions.
Hello sir please can you help me thanks. I'm disabled and have a mobility scooter, I wanted to charge the battery using a 2500 watt inverter. The scooters charger 8 watt, I connected everything and the generator started to charge the batteries, however after around 10min I noticed smoke coming out of the charging vents,. Question, hiw can I charge the scooter with a generator thanks.
It's hard to believe the charger is 8W. If smoke came out of the charger, then it's most certainly damaged. You can get a small inverter generator with electrical plug on it and charge your scooter that way. You will have to get a new charger though. Make sure the charger is compatible with the battery.
@@cleversolarpower Sorry 8amp the charger is.
Great example but you failed to mention that your 3000 watt Inverter needs to be 48 CDC. Most of us run 12 VDC inverters. I have a 3000 watt and have 6 100 amp lithium at 12 vdc. My problem was not enough solar wattage, had 360 on roof of the van, but my mppt couldn't handle my second 360. So had to buy a mppt thar could take 720 watts, I also will be installing a 100 amp AC to DC inverter for shore power use when pluged in to go along with the 40 amp DC to DC I have wired in already. I don't plan to run a 110 vac on the van or a microwave for multiple hours at a time. So I should have enough power to run all my 12 vdc systems. BTW, you would need to install a 48 vdc step down inverter to 12 vdc to run all of your 12 vdc appliances.
Thank you. I had plenty of questions about that. I too have a 12v 3000, but I just began to experiment with how many batteries I would need for continuous power without fail. Now I know I need at least 6. I have other inverters on order to have portable power. *I learned a lot from you, Thank You!*
You don't really need a 48V inverter for a 3,000W inverter. But if you can you should do that. step 1: ensure your C-rate is ok, by having higher capacity batteries. Step 2: increase the voltage of your battery so you can use less thick wire, thus save money.