Can anyone help me build a power inverter - Page 1
Forum section: electronics / projects

author: Samuel1477
author_rank: Contributor
timestamp: November 24, 2020, 03:26:07 am
content: So I recently purchased 4 apc 1300s. It has now become my life goal to tear them apart and use the parts to build my very own sine wave inverter. Is there anyone who could help me with this. As I am a fairly smart person but not an engineer by any means. 5his is my attempt at learning more about inverters. I always get to this point and end up giving up. I will not give up this time. I may be a little late for this part but here it is.... my whole idea for this project came from wanting to reinvent the inverter lol.... I wanted to design a inverter that is stackable. Like a 1500w inverter that if you have 2 they connect together and boom 3000w. Inverters have more than confused the hell out of me. From regular car inverters to UPC systems. The more I research the more confusing the system. I have learned a lot. Please advise me futher I will post any info needed. Anything helps.

author: Samuel1477
author_rank: Contributor
timestamp: November 24, 2020, 03:31:50 am
content: Hi everyone. My name is Sam. I am new to the forum. Half noob to electronics but edgar to learn! I am trying to design a product. I'm not even sure I can do it. I am a novice let's say. But I love batteries and I feel like I have some good ideas. I am hoping to maybe get some advice. And possibly some resources. I need to find some good power supply and a pure sine wave inverter. Any info is greatly appreciated. Also I tore apart a 1960s electronic organ and it has these rods. I just have a strong feeling they are worth something.That is my original post above. One thing to add is I did find out that the rods from the electric organ were 80% silver and 20% gold 7.4oz wonder if the 5kg of wire is silver too...

author: james_s
author_rank: Super Contributor
timestamp: November 24, 2020, 06:47:12 pm
content: This is one of those things where if you have to ask then you are in way over your head. We cannot provide you with the equivalent of an EE degree starting from scratch, you will have to learn the basics on your own and then people can provide help with various details. Have you seen Khan Academy? You can take a lot of online courses completely free of charge. IIRC they have a curriculum for EE.

author: jonpaul
author_rank: Super Contributor
timestamp: November 24, 2020, 07:48:20 pm
content: Sam: BRAVO for your interest and enthusiasm. As an EE since 68 and having designed many converters and inverters, I agree with James S, that you cant do it by the reverse engineering, forum or just experimenting. Errors in design, parts section or tests usually result in the power transistors blowing up, and sometimes other damage.Suggest to learn the engineering, by reading some good papers and books. We can recommend if you like.A 1000W since UPS is not only complex, with custom ICs and transformer, but also dangerous as voltages of 360 VDC are present.Also, many APC UPSs eg 2200 VA are sometimes available cheaply on Craig's List with dead batteries, easily fixed.Just the ramblings of an old retired EEJon

author: Samuel1477
author_rank: Contributor
timestamp: November 27, 2020, 01:17:20 am
content: I do have the basics to some extent. I am just wondering if I can pull the analog hardware from the Apc 1300s. Use those components with an arduino. To make one big and more efficient inverter. I mean yes the APC 1300s are complicated in and of themselves. But if I use an arduino in place of the APCs ICs doesn't it make the inverter circuit much more simple. I will definitely look into those courses. Thanks guys.

author: james_s
author_rank: Super Contributor
timestamp: November 27, 2020, 01:56:40 am
content: Technically you probably could, but it's certainly something I'd consider an expert level project.If it were me, I'd sell the UPS's to people who need a UPS and either buy a pure sine inverter or design one and build it out of new parts.

author: Samuel1477
author_rank: Contributor
timestamp: November 27, 2020, 06:51:34 am
content: What is a better way to learn! Lol. I will look in to those classes James. If I do continue with the project. I will document everything and film it for your enjoyment. I am known to take on projects that are above my head. Seeing then through to the end. By the time I finish AI will have taken over. I will post what I decided to do soon thanks for all your help.

author: Berni
author_rank: Super Contributor
timestamp: November 27, 2020, 10:51:52 am
content: Nice to hear your enthusiasm.But as others said projects involving high voltage and power electronics are not a good fit as beginner learning projects. High voltage is much more dangerous when you don't know what you are doing and high power electronics tend to fail in pretty spectacular ways. So in the process of it you could get shocked while also blowing up those inverters by simply sending in the wrong drive waveforms.If you enjoy power electronics then work on things like small 12V MPPT solar charge controllers and the like. They are safer and much more difficult to blow up.

author: PaulAm
author_rank: Frequent Contributor
timestamp: November 27, 2020, 03:52:28 pm
content: To make a bad analogy, this is like design/build an Indy car engine after taking apart a lawn mower engine.If you do continue to work on this, at least wear effective eye protection and use appropriate sheilding. When (not if!) these things blow up they can send shrapnel everywhere. Treating the prototype like a live hand grenade about to go off is about the right level of paranoia.If you want to build a sine wave inverter, there are lots of designs on the web. Start small, have success, gain knowledge, then move up.The idea of a "stackable" inverter is not new. I have an 8KVA inverter that can be paralleled with up to 3 other units, but they require a communications channel between inverters for them to work. Load sharing is not a trivial problem. List price on that inverter was well into 5 figures.

author: BrianHG
author_rank: Super Contributor
timestamp: November 27, 2020, 04:16:07 pm
content: Not I not saying it is safe...Here is what I've have done:I got a quality modified-sine wave inverter which has a good step-up switcher core.On the HV side, I tapped the DC and placed it through a PWM inverter circuit using a PIC driving a few mosfets with an amplified sine wave where the peaks were a little squished, sorta like an amp with a smooth soft clipping due to too much gain to make up for the 145v dc not being exactly enough for a full true sine wave (need 165v DC for that), yet I will still get a 115v rms and none of my attached electronics have that square wave nasty buzz anymore since the result is just shy of a true sine wave with no sharp edges. AC motors also seem to startup properly and run fine as well.Also take a look at class D audio amp driver ICs. +150v ones exist which just have 4 'Gate Driver' outputs with bootstrap caps with high side drivers to drive your own bank of N-Channel Mosfets. You will need a tuned output RF choke + these amp ICs have analog in and use output feedback to regulate your output. You will need a MCU to synthesize the 60Hz sine-wave feeding the class D amp driver.Do not attempt this for 240v mains...

author: james_s
author_rank: Super Contributor
timestamp: November 27, 2020, 07:10:43 pm
content: Quote from: PaulAm on November 27, 2020, 03:52:28 pmI once had fragments of mosfets ricochet off the ceiling after a particularly exciting failure. Since then I usually set a small lexan blast shield over that sort of thing whenever I'm dealing with something that might fail catastrophically.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: November 27, 2020, 08:17:24 pm
content: I just don't see how 'come back in twenty years after your studied electronics and talk to us, kid' is very helpful.

author: jonpaul
author_rank: Super Contributor
timestamp: November 27, 2020, 08:41:50 pm
content: Suggest to start on a simpler problem, eg SST Tesla coil or squarewave inverter to get experience.You need a minimum lab to do power electronics: 10-20A variac, 2-4 ch digital scope, current and voltage probes.Jon

author: Samuel1477
author_rank: Contributor
timestamp: November 27, 2020, 08:47:15 pm
content: I am a welder / Machinist. So high voltage and explosions are not entirely unknown to me lol. So here is my full dream/idea. I want to design a inverter that can be produced for cheap. That can be stacked together seamlessly. So when you connect them they snap together and become one inverter. My hope is to be able to design something like a 1500w inverter that's end pricing is $60-$75 at most. Without compromising quality. Can this be done? I will start smaller. And work my way up.

author: james_s
author_rank: Super Contributor
timestamp: November 27, 2020, 09:35:13 pm
content: 1.5kW true sine inverter at $60-$75? When the Chinese factories can't come up with something decent at 3-4 times that price I don't see how you're going to manage. For a one-off it's possible it could be done using salvaged parts from old UPS's and such but the problem with salvaged parts is that stuff like transformers and inductors are probably going to be custom parts specific to that model UPS and not something you can easily get quantities of.With sufficient determination an inverter is something a hobbyist can build, but you have a long road ahead of you. You're probably 2-3 years of diligent study away from a point that anyone can give you much in the way of specific advice. Traditional EE is a full time 4 year degree, you can probably skip some of that if your interest is only in one specific field but you're going to need to have a solid understanding of the basics.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 27, 2020, 10:25:19 pm
content: Quote from: Samuel1477 on November 27, 2020, 08:47:15 pmyou're day dreamingtotally unrealistic, dangerous and unprofessional to say the leastfor a mere 60-75 $ wow even a cheap, really cheap china inverter will cost more than that, and it will fail miserably

author: Labrat101
author_rank: Unknown
timestamp: November 27, 2020, 11:08:21 pm
content: I just read this thread . total agree Playing with large inverters are not for theNovice.I have a Pure Sine 3000kva inverter that some one brought in for repair . These things are not that simple . Just think if your inverter was 100% efficient 1500w @ 12 volt full load is 125 Amps. This can make a regular car Battery boil . The cables have to be 15mm at least. And most of the Pure sine inverters use 4 stages in parallel if one stage fails things can start getting very hot .And Some has already mentioned those output Mos Fets can get very angry.The internal voltages 350 v running at a frequency higher than some Multimeterscan read . So you will think that its not working .. But your finger will tell you other wise.I have worked on these thing and they still scare me . Even after 40yrs in the trade of electronics . I would be happier working on the 3 phase primary 600vac x 3ph~.which is my licence Max.To Build one for $60-$75If you want a Pure Sine 1500w Inverter or Larger ... Go and Buy a new one .

author: BrianHG
author_rank: Super Contributor
timestamp: November 28, 2020, 12:27:10 am
content: Try 600$ - 750$.

author: Pawelr98
author_rank: Regular Contributor
timestamp: November 28, 2020, 12:36:32 am
content: Quote from: james_s on November 27, 2020, 07:10:43 pmI would do a simple thing called series lightbulb.That usually limits the available power that can blow up things.Capacitors still do have charge but for basic no-load/light load testing you can get away with much smaller ones.This way the bang won't be as loud or dangerous.I don't toy around with inverters, just simple SMPS.In my case I have my own isolated 230V source with a current limit, consisting of 24V 500W PSU inside 1000VA UPS.It will shut off during an overload (on both DC PSU side and AC inverter side).Another thing would be to start at a reduced input voltage and monitoring how the inverter operates.For a simple Half-Bridge I started at 30V to ensure that all the switching waveforms look about right and that all the windings are in the correct phase.After that It was 100V DC and slowly going up to 325V, observing the waveforms closely.Oh, and still with a series light bulb.Once I was confident enough I switched it to the mains and shorted the light bulb.It's a longer process, where you go step-by-step, from the basics to the bigger things.First make a small 50-100W inverter, using 12-24V and a transformer.You will learn how to actually make a sine wave inverter, iron out some basic issues on your own.Then step up to 200-300W and so on.Also there are some cheap boards like EGS002 which can be a great learning material or even used for building basic sine-wave inverters.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: November 28, 2020, 12:48:20 am
content: Quote from: Samuel1477 on November 27, 2020, 08:47:15 pmHave a look at micro inverters that are being used underneath solar panels. The wheel's already been invented. The costs you are shooting for will only require reducing materials needed for sufficient heat management, which is the main thing that kills cheap inverters.Contact some green/off grid companies with your power requirements. They are adept in merging the customer with exotic components and generally can advise how to connect it all up and help will future expansion capacity.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 28, 2020, 01:17:26 am
content: Can't help you with a 1.5kW inverter for $75, but I do know of a way to get a 10kW+ inverter for less than $500 in parts: hack a Prius inverter.

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2020, 02:32:17 am
content: Quote from: Pawelr98 on November 28, 2020, 12:36:32 amI'm well aware of the series bulb trick. This was a ~1kW SMPS for a Kodak dental xray head. The power level was high enough that a bulb capable of limiting the current under a fault condition would be insufficient to carry the normal load, and even if it is, the required bulk filter capacitors at that power level store enough energy to make things exciting. The bulb can't be placed behind the bulk capacitors because it adds too much stray inductance and makes things go crazy.I thought of this project specifically because the OP is inquiring about building an even more powerful inverter which is going to bring the same challenges.

author: Pawelr98
author_rank: Regular Contributor
timestamp: November 28, 2020, 04:19:25 am
content: Quote from: james_s on November 28, 2020, 02:32:17 amThat's why I would remove some of those input side capacitors and first test things on no-load or light load.When things seem to work, just bring back some of them and increase the current limit by placing a bigger bulb.Increase the load and observe how things work.When building an amateur SMPS, where the max power the converter can handle is not really known (because almost all data such as core material are unknown) there's only one way to do it.Bit of trial and error but you can learn from that.Also, the things I was doing when working under a cheapskate boss.Extra stray inductance would be one of the least important problems (I was repairing welders and several other medium power SMPS).After repairs those things worked without any issues though.One thing that puzzles me is why OP wants single phase inverters of 3kW or more.At 115V it would make no sense whatsoever. At 220-240V it makes more sense.Then of course a better situation would be a three phase design, as power can be split among more elements (certain designs just use three single phase inverters working together).In the latter case it would be more of a matter with proper synchronisation (120° shift) of those APC UPS units using some external means and software/hardware "hacking".

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2020, 08:14:33 am
content: Quote from: Pawelr98 on November 28, 2020, 04:19:25 amHe's in the USA, 3 phase would be useless in a domestic environment as it's only used in commercial and industrial environments. Our houses are fed with single split phase 240V, 120-0-120 from a center tapped transformer with the center tap bonded to earth. The small loads are all 120V with the branch circuits distributed between the two legs, large appliances that need 240V are fed from both legs. A 3 phase inverter won't work, and a single phase 240V inverter won't work, you need either single phase 120V or split phase 120/240V if your aim is to power domestic equipment.

author: BravoV
author_rank: Super Contributor
timestamp: November 28, 2020, 08:38:08 am
content: Yet another ... "Dad, I've mastered how to use a hammer and screw driver, can we build a jet engine Dad ? Pleaaasseee ...." .. kinda thread ...

author: jonpaul
author_rank: Super Contributor
timestamp: November 28, 2020, 09:20:00 am
content: Hello again:In USA the 120 V mains also have 230V for large appliances.Ratings for consumer/residential connectors limits the max power to 1875W at 120V and 2X 1875 for 240VThus a 3kva inverter needs 240V and shall have a 360V bus.Also many commercial units such as the APC use custom made transformers and custom programmed ICs to synthesize the since wave.Finally a minimum electronics lab will cost $1000 without the current probes required.In respect to the OP, even an experienced welder can get into trouble on such a project.Bon Chance!Jon

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 28, 2020, 01:21:53 pm
content: Quote from: james_s on November 28, 2020, 08:14:33 amDon't see any reason why you can't use a 120/208V inverter at home, in fact in densely populated areas, it's common for apartments to have access to two phases of 120/208V 3 phase, distributed across units such that the overall load would be close to balanced.You could also separate the 240V loads from the 120V loads and have a separate inverter for each. That often works out better for reducing standby losses since 240V loads generally require a lot of power. It also allows you to do V/Hz control of the 240V loads to a much greater extent than if you had to make sure the 120V loads would continue to see a minimum of 100V/50Hz.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 28, 2020, 06:30:04 pm
content: Learning about what you can do and can't do isn't obvious first, this skill needs to be learnt like any other skill. Sayinghow longit takes to learn to do X is even more difficult, even seasoned professionals tend to seriously underestimate this from time to time.I can relate to the OP because I went through that kind of phase as well. It could be called "child's play", but I felt like I'm dead serious; I felt like I can build anything. And the key is: just start doing it! That's the only way you find out slowly what it takes to actually do it.It's an interesting hybrid mix of just child's play with some serious aspects in it, and the level of seriousness slowly goes up, and then it becomes an actual profession.I started at about age 4-5. Drew schematics of cars, laser guns, electric motors, and so on, built random things from batteries, wire, bulbs, motors and repurposed through hole components removed with side cutters. Great thing in being a kid is, when you draw a laser gun and actually get just a light bulb glowing with a battery, you are not disappointed at all, quite the opposite; you can play it's an actual laser gun!At about age 12, I finally started to have some remotely realistic idea about what can be done, and what can't, separating from the child's play side. Finally, at about age 30, I could call myself a professional (and, actually design and build a proper power inverter, if needed).Even if you start the learning process as an adult, you still have to go through the process of finding out what can be done and what it takes.

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2020, 06:45:38 pm
content: Quote from: jonpaul on November 28, 2020, 09:20:00 amThat's not entirely true. There is a 120V 30A standard that is commonly used for RVs and boats and you can certainly have multiple 15 or 20A sockets on an inverter or generator. 3kW and larger 120V inverters and inverter generators are not uncommon. Most larger conventional generators for the North American market deliver split phase 240V but the vast majority of inverter models are single phase 120V only.https://www.amazon.com/Giandel-Inverter-Outlets-Control-Display/dp/B07CTGJ46T/ref=sxin_10https://www.amazon.com/GoWISE-Power-PS1004-Pure-Inverter/dp/B0131PZ9J2/ref=sxin_10https://www.amazon.com/EDECOA-Inverter-Controller-Hardwire-Terminal/dp/B07PVG4GVW/ref=sr_1_11https://www.amazon.com/Champion-4000-Watt-Ready-Inverter-Technology/dp/B01M3R711N/ref=sr_1_3There are many others, these are just a few examples I found.

author: james_s
author_rank: Super Contributor
timestamp: November 28, 2020, 06:48:50 pm
content: Quote from: NiHaoMike on November 28, 2020, 01:21:53 pmThere's no reason you couldn't use one to power loads, but if the goal is as a backup supply wired into the panel you won't be able to make use of all three phases and there would be no great advantage. Not that it really matters since this is all academic at this point.

author: cpuerror
author_rank: Regular Contributor
timestamp: November 28, 2020, 11:33:38 pm
content: You can watch some of knurlgnar's videos on paralleling APCs and invertersBut it not an easy or safe project and if you think you can make a 1500w sine wave inverter that is stackable for $75 you may be in over your head.

author: Samuel1477
author_rank: Contributor
timestamp: November 29, 2020, 01:03:26 am
content: Hey thanks you guys are great. I love this community. I grew up without me dad so. Reading some of this stuff feels like a dad trying to convince me not to blow myself up ect ect. I am learning alot just by reading. I promise to use the proper PPE and be careful with high voltages. When pushing components to their limits and beyond. Shoot maybe I could send the results to the manufacturer for quality control. I can see it now "Sam's pocket 2kw inverter/personal heater" lol what about design a new super MOSFET lol I mean every other component has a super version couldn't a super MOSFET be ideal for high frequency inverters

author: james_s
author_rank: Super Contributor
timestamp: November 29, 2020, 02:32:17 am
content: There already exist parts that could be called super mosfets. Compared to what was available just 20 years ago you can get parts now that can switch much higher currents at much higher voltages much faster and they are more robust and cost less. I remember back in the 80s my family had a sailboat and I always wanted an inverter but even the basic square wave ones were expensive then, as in the equivalent of ~$2k for a 1kW squarewave inverter.

author: coromonadalix
author_rank: Super Contributor
timestamp: November 29, 2020, 03:31:24 am
content: i use "super mosfets" at my job at 45$ usd a piece, your budget is blown loll

author: Pawelr98
author_rank: Regular Contributor
timestamp: November 29, 2020, 03:59:11 am
content: Quote from: james_s on November 28, 2020, 06:48:50 pmIf the load is balanced then the power going through each switching element (or each inverter) will the same.That's why I would say it's a better thing, if you can make it more/less balanced.Of course this implies either a true three-phase load (eg. induction motor) or several single-phase loads that can make a balanced load.I don't know what transformers are available out there on the used market in the US but over here 400V/230V autotransformers are fairly cheap.Building an 400V (still can be controlled using cheap drivers like IR2101) inverter for further losses cuts and then going after an autotransformer to step it down.And to be fair, in europe almost all new homes have 3x400V available, even though we don't (usually) use industrial equipment at home.Even my small apartment has all three available.It just makes more sense for load balancing and power losses.

author: james_s
author_rank: Super Contributor
timestamp: November 29, 2020, 04:24:21 am
content: No doubt there are advantages to 3 phase but you don't see it in homes here, ever. The closest you get is apartment buildings where the building has a 3 phase feed and each apartment will get 2 of the 3 phases to a standard split phase residental panel or large farms where there are irrigation pumps and things.

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 29, 2020, 05:00:10 am
content: Quote from: Samuel1477 on November 29, 2020, 01:03:26 amcan you tell us what this IRF3205 does? (1st attached picture) can you drive it using PWM (variable frequency preferably) signal out of arduino so you can output 120/240Vac on secondary inverter transformer side? if you can answer and do those, you are on your way for a 5KW super true sine wave inverter, attached circuit is using full-bridge mosfets i suspect to drive the inverter transformer. if you cant answer those, be patient, read, study and experiment slowly, this is not a 1 week nor 1 month job however smart a person is. thats why you heard a lot of nay sayers when you ask in such a way, its like asking, can anyone help me building a super car? or a fighter jet? there's no amount of forum thread can explain that to you. please forgive them and us..btw, the circuit snapshots was taken few days ago during a few minutes blackout. because i was pissed off the batteries giving up too soon (about only a year life) and i wonder why this circuit can kill batteries so soon. i'm thinking to improve or understand it and make even better one if i have free time later, just like what you plan, minus the 2-5KW thing. i had few minutes in the dark, computer is dead, so it was a peaceful (hot) time dismantling it with help just a screwdriver and a torch led light. it is my KOSS 1KVA UPS, i also take out my 2 unit 500VA Contronetix UPSes and i thought paralleling them later to get 1KVA capacity. exactly like what you have in mind (3rd and 4th picture) but now electricity is back on, so i can continue with my other tasks, this plan may continue during another long blackoutjust to give you some ideas. cheers.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 29, 2020, 08:29:11 am
content: Quote from: Samuel1477 on November 29, 2020, 01:03:26 amNah, that's not the problem. People are just saying that if you start from where you are now, it will takeyearsof full-time learning. So it's a lot morecomplextask than you think it is.It's like "daddy, can I build a space rocket and go to the Moon?", not "daddy, can I use a knife to make bow and arrow?"But that's not a reason not to start.OTOH, it will be more rewarding to pick subgoals or smaller projects first. Building a basic buck converter is a good introduction to power conversion, and even that will take time. Try to convert 12V to 5V with a MOSFET, diode, inductor, capacitors and try to figure out how to do it.

author: Labrat101
author_rank: Unknown
timestamp: November 29, 2020, 07:12:01 pm
content: This is a customers 3kva Inverter that he tried to repair .And failed and killed the wholeoutput stage. Plus a bonus bill from hospital for burns.Runs from a Large Accumulator Bank .When running on full load Draws nearly 250AMP on 12 voltAnd this is only a baby inverter .Have Fun .

author: Samuel1477
author_rank: Contributor
timestamp: December 01, 2020, 12:45:13 pm
content: I grew up without a father so it's really comforting to see all of you guys telling me I'm in over my head. Or that I am going to blow up a bunch of MOSFETs. Thank you everyone for all your info. It really helps. Can anyone point me to a cheaper pure sine wave inverter 2kw or more I am also looking for a good power supply to charge batteries. One last important thing. What voltages and power levels are considered to be at the dangerous level. I thought as long as it's under 60v your pretty much ok. That is not to say that 2v and 5000A won't do damage but is there a rule of thumb so to speak. I started Kahn Academy as well. Crash course lol.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 01, 2020, 01:01:30 pm
content: Stay below about 50V AC or 100V DC.Currents are dangerous as well even if voltage is low: high current can melt and vaporize metal, causing burns or setting something on fire. Fusing helps. For example, if you play with a car battery, first wire a fuse right at the battery terminal (in series with either of the terminals, choose plus or minus), be careful doing that, then protect the battery terminals from accidental touching with metal objects. After the fuse, it's a lot safer. Use a fuse value that's enough for what you need, but not much bigger.Past some 50A things easily get HOT!

author: Labrat101
author_rank: Unknown
timestamp: December 01, 2020, 01:07:41 pm
content: Quote from: Samuel1477 on December 01, 2020, 12:45:13 pmSorry To hear that . But it should make you stronger and more aware of Life.Its hard to recommend it all depends on what Batteries you are going to use.If Car type batteries (example) I would go for 48v with a 2kva inverter other wise you willneed big ass lead acid batteries . You will have to do the maths and so home work.remember there is no free lunch in using an inverter .2Kva @ 48v = 41 amps (full load) so a 40 amp\ hr Battery will last less than 1 hour.That's with a 240vac inverter .. If your 110v it will be slightly different arrangement .Rules of thumbs . Not really just keep Murphy out .And follow local laws and regulations if they a ply to your home/flat etc.Get a licenced electrician to come and see . and advise .

author: james_s
author_rank: Super Contributor
timestamp: December 01, 2020, 06:24:32 pm
content: Quote from: Siwastaja on December 01, 2020, 01:01:30 pmMy dad has a scar on his finger from a ring that got between a wrench on the terminal of a car alternator (connected directly to battery+) and a grounded bracket. The short caused the ring to get very hot very quickly. There's a reason they say to disconnect the negative terminal first and remove any metal jewelry when working with electricity.

author: poorchava
author_rank: Super Contributor
timestamp: December 01, 2020, 07:55:25 pm
content: Mains-related power electronics are no joke. Especially, that if you have a 360 or 400V bus, the transients can easily be 1.5x that. I'm currently working on something that is essentislly an AC-DC-AC arbitrary waveform inverter/generator at 3kW. In order to keep hearing at acceptable level it recirculates energy from secondary to primary, uses regenerative clamping etc. Complex stuff. DSP generates like 13 different PWMs... The DC bus stores something like 180J. This is neither safe, nor simple to paly with. Definitely not something you can slap together out of salvaged parts...I once detonated the charge from main caps about 30cm from my face. It evaporated about 15cm of 1mm.squarr wire.... The only success in this was, that my pants stayed clean.... Again those power levels are not joke...

author: coromonadalix
author_rank: Super Contributor
timestamp: December 01, 2020, 08:16:24 pm
content: I think this thread should stop here for @Samuel1477If you dont understand all the dangers and intricaties of your own design, we should stop discussing this furtherIt simply show some stubbornness of your part and no one will really help you to design something dangerous for safety / security reasons and i would not or do not want to be accountable of anything that could happenmy 2 cents

author: Labrat101
author_rank: Unknown
timestamp: December 01, 2020, 08:17:24 pm
content: Quote from: poorchava on December 01, 2020, 07:55:25 pmYou were very luck .Edit .. Totally agree with @ coromonadalix enough is enough .

author: Samuel1477
author_rank: Contributor
timestamp: December 02, 2020, 02:21:01 am
content: I am doing more research. I wanted to go to MIT before I cut the tendons in my hand and was prescribed copious amounts of oxycontin. I decided to be a street pharmacist after that. I have since realised that it was not a good career path. I have begun my journey into the world of electronics. Now that everyone knows my life story. Could anyone point me to some inverter schematics or kits in the simplest form. Small ones of course. I am a welder by trade I do understand what high power is. I also install signs for a living don't see as much now with LEDs but I have removed some huge ballasts. Thanks again everyone.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 02, 2020, 06:39:09 am
content: Quote from: Samuel1477 on December 02, 2020, 02:21:01 amwhats wrong with welding career? its good enough money if specializing in..

author: james_s
author_rank: Super Contributor
timestamp: December 02, 2020, 06:32:12 pm
content: I don't recall ever seeing an inverter kit, and you're a long way from the point where schematics are going to be any use to you. Get the education first, learning the basics will take you a while and there isn't much we can do for you until you've got a handle on that.

author: poorchava
author_rank: Super Contributor
timestamp: December 02, 2020, 09:35:36 pm
content: This is just different from stuff like Arduino and other similar platforms, where you can do stuff by trial and error and either it works, or you give up, or the electronics give up and you buy more from eBay. There is also A LOT of knowledge on forums and many people, who are on similar, entry level. Nothing wrong with being on the entry level, we have all started somewhere and somehow.Kilowatt-range mains voltage inverters are probably as far as one could be from beginner level. Contrary to some other stuff, you must have certain knowledge, experience and solid background knowledge to do this. Learning by trial and error is definitely not the way to go . If not because if explosions, the just because of money: a good mains rated fet can be like 10€, and we're not even talking SiC here (although it's not much more expensive). And they usually die in pairs and take other components with them too. In the last project, I literally had a 3L jar filled to about half with dead transistors and I know what I'm doing (for the most part at least...).This is the same situation as with cars: getting a 1000HP tuned car with stripped safety systems is probably not what you should do a day after getting your driver's licence... And in that analogy you haven't started the driving school yet.