Introduction: Transforming a 300W Sinewave DC/AC Mini Inverter to a 5000W Monster

Picture of Transforming a 300W Sinewave DC/AC Mini Inverter to a 5000W Monster

I was planning to build a PIC microcontroller sinewave inverter and while browsing the internet to buy the necessary items I got accross this little 300w ready made pure sinewave inverter which would cost less than all the main items I was searching.
An idea flashed in my head to try to drive my "already have" square wave inverter's power stage from this ready made thing so I went ahead and ordered it.
After receiving the item I ran some tests on it and was surprised of the many hidden options this tiny thing packed:
-Built-in PWM maintaing a stable 230v at all times.
-Over voltage "+15v" and under voltage "+11v" cutoff.
-Low battery audibale warning.
-Overload cutoff
-Waveform distortion :<5%

Actually 300w is way too much to drive the power stage, 100w would have been more than enough and the price would be much less but unfortunately I didn't find one.

Anyway.. The idea was a 100% success, I connected the mini inverter to my power stage that I already have built from a previous instructable and the monster came to life just as was expected :)

Of course you can adjust the power stage to your needs following the table of my main instructable.


โสภณไ (author)2017-12-24

what happened to Nick? It's a 268 volt out put. But enough of the filtering system, the power is only 168 volts.

Muhammad BulhaqiS (author)2017-09-14

hello sir, i found the problem on the output transformer ... the trafo is hot like a short current, when i check the mosfet and the transformer looks fine,the voltage on "drain" mosfet is dropped when i connect to battery

feijooster (author)2017-05-30

i don't understand something. i need to make a 5000w inverter. but. i need 84-0-84 + 20 transistors to get 5000w????

giftemma411 (author)2017-05-06

i can't view any of your inverter pictures because of network problem..can someone send all me nicks inverter instructables to
Am researching on inverter....i will appreciate anyone who send me even the author

Electro46 (author)2016-04-16

Hello Nick,

I am new here and would first like to say thanks for this project of instruction. Had a few questions on the transformer useage and inputs/outputs. I am guessing that the 12-0-12 trans is rated at 220v ac input and 12v+ dc output in order to supply good current to gates? I also was wondering about the 84vdc tap trans with 220v ac out. Many may not have the means to supply 84v DC via batteries; with this being the case, can't we just use a buck converter and cap to stabilize and provide voltage to center tap? Note: transistors mention are pretty durable and I have found a few alternates to supply power to this wonderful design; ex: MJ15022, rated at 250w 16A 250v. Please assist me...

Electro46 (author)Electro462016-04-17

Hey Nick,

Thanks for the update. I will proceed with the 24 trans, any particular brand? Your recommendation is highly appreciated.


Nick_Zouein (author)Electro462016-04-17

Hi Electro46,

It not a rule to use a 84v transformer, the power stage trans's voltage is related to the DC supply, if you're operating on 24vdc then this trans should be 24-0-24/220 and so on. Read my other instructable to get a clear idea on the transformer's power stage and what to use.

saetech1 (author)2013-12-28

Hi Nick,

I have a doubt about this unit. That is when I am using the 300watt sinewave inverter, the out is connected to a 12-0-12 volt transformer. According to your table the 5kw inverter must have a 84 dc volt input. In drawing you are showing the last transformer as 84-0-84. How does this happen will the voltage automatically increase from 12 to 84 after the transistors.

Hwolfw (author)saetech12014-02-16

Notice at the bottom of the diagram, he has 7 12V batteries. The +84VDC comes from all 7 batteries in series.

dineshg1 (author)Hwolfw2014-08-24

please refer drawing carefully ,that 7 battery's connected before 220 / 12-0-12, 0.5A transformer

Hwolfw (author)dineshg12015-09-05

7 battery's connected yes, but only one is being used for the 300W Sine inverter. The full 84V is being tapped into the 84-0-84/220 Transformer at it's center tap.

dineshg1 (author)Hwolfw2014-08-24

please refer drawing carefully ,that 7 battery's connected before 220 / 12-0-12, 0.5A transformer

RusticoL (author)2015-04-13

hi nick can i used transistor d1047 for monster inverter?

RusticoL (author)2015-03-19

hi nick

i build ur monster circuit n it works,but the problem is,the power output is to high,it goes to 380 volts ac,i used d1047 transistor and my transformer is 12vdc/220vac 45 amps.what is the exact transformer do i used,thanks more power,i nead ur reply,

SolarE1 (author)2014-12-09

hi nick,

does the output of this monster is a sinewave?

from 12V DCto 220Vac (sinewave)--> going to 220vac transformer then diode(squarewave),.going to power stage, where does the conversion of sqaurewave from diode to sinewave occurs?

thank you, im just a little bit confused.

KHARSANG (author)2014-11-18

Is it necessary to use 300W UPS for this project? Can I use UPS with lower wattage, say 100 watts as we only need 12 volts pure sine wave input from the inverter to feed the 2N6227 MOSFETs?


aaronandamerica (author)2014-11-17

can anyone help me with this? i have spent more than $100 on transistors and bought a oscilliscope. im going 48 volt to 115. have all the parts but keep burning transistors, using 2n3055. have more on order. my problem is what base resistor should i use? would like to use 48 volt for switching but my next attempt will be 100 ohm at 24 volt switching 48-51 volt collector emitter. im a do it yourselfer but the math for transistor base resistors is to confusing. seems like 100 ohm at 24 volt is somewhere in the middle of what they like if it works i will try 220 ohm at 48 volt for switching power. anyone willing to plz help.

tplim (author)2014-10-12

Can i uses IRFP260N instead of 2n6277? If yes, which part of the "" circuit I needs to change?

flogy4031 (author)2014-10-04

preaty cool ! nice work!

Wouldn't it be easier to use some IGBTs?

and how about recharging the battery pack? 84v chargers are hard to find and also pretty expensive... could one use a simple charger circuit with 7-8 ATX PSU linked in series?

anyway I'm definitely going to build one :D

tmsantos (author)2014-09-11

você não pode gravar um video para podemos ver como ficou .

seria muito bom ,

dineshg1 (author)2014-08-24

hello sir how can i convert my Microtec 600W Square wave invertwr in to sine wave ???

ggadogbe (author)2014-03-27

i think this is wast of funds to run 80v with this inverter i think 12v 600watts pure sine wave is best. Or 24v 1.5kwatts pure sine wave inverter. Is much better that thi.

power4me2use (author)2013-12-05

Hi Nick,I am going to build your 300w to 5KW power monster. I just have a few questions
Some guys say that a modified sine wave inverter can damage electric components in the house,is this true?
If my supply voltage to the inverter is 144v would I then require less amps for the same output than with 84vdc?
Anyway,thanx for this project I will keep you posted

alex young (author)2013-10-17

hello Mr Nickk could u incorporate a feedback voltage correction circuit to this design .This is my greatest problem the voltage falllls with varing loads. If u could get this circuit to work just like ur other work horse inverter I would need no other inverter please help me here to get this problem corrceted. Thank u and keep the good work going

maclee4real (author)2013-08-28

hi nick
how is the system gonna charge cos with the charging system of the ups, it will not be able to charge fast. and will the TIP122 withstand the 12v from the transformer?

Zaman (author)2013-06-06

hello nick.
really nice project.
at the moment i am collecting parts and i couldn’t found 2N6277 in my area so can you suggest something else as alternative. in one comment i saw 2N3773 but again i couldn’t found this one either.

Nick_Zouein (author)Zaman2013-06-08

Hi Zaman,
why not build a MOSFET version

Zaman (author)Nick_Zouein2013-08-18

indeed its a good idea but mosfet dosent last long. anyway i can try that too. currently i am looking for 5Kw transformer. the cost is too high these days here so looking to build my own. may be this way i can save some cost. and need assistance too for build.

Nick_Zouein (author)Zaman2013-06-08

2n3773 is a very common transistor, strange why you can't find it, anyway any 150w replacement that you're parts supplier suggests should work, you can just get a couple for testing reasons.

yoyllyoy (author)2013-07-31

hi nick
Interest charges are too great.
Thank you so much for the help.

Based on this, but It does not work, and some experiments. I would question seeking some advice

In Korea, as an alternative because you can buy 2n6277
Specifications: ((VDSS) 200V, (ID) 30A, (PD) 150W, RDS (on) 0.085Ω, Single N-Channel HEXFET Power MOSFET)
Specifications: (NPN 250V, 16A, 250W, 60 (hfe), 4MHz (ft))
Can I use any of these?
Can I substitute irf250 mosfet version?
Can I use several possible when 5000watt?
Or something else while I would appreciate it if.

Transformer specification 48V-0-48V transformer capacity, and if the 3,000 watt transistor called a rightfully deserves some do?

In addition, two 84V-0-84V transformer specifications and is 3,000 watt transformer capacity at this time is some transistors?
(I to have the above two transformer.)

alex young (author)2013-06-04

Thank u Nickk I will try this and let u know. I am running 120v AC I really hope this works because I love your power stage and not able to build your other sine wave inverter as yet. Thank u for ur support

alex young (author)2013-05-27

hello Nick I am still having some problem here with the AC volts falling off i have 9.89v on the gates and still the ac falls off from 123 to 111 with certain loads. I am testing this with a modified sine wave inverter before i buy the right sinewave inverter does it have to be a sine wave signal to work.Please help me here Nickk what else should I look for. I still have to bigg u up Nick i am running my house full time on ur other version 1500watts i call it my commercial inverter its a work horse to handle heavy loads.God blesss u

Nick_Zouein (author)alex young2013-06-03

Hi Alex,
1- "Falling from 123v to 111v" ? Does this mean that you are running a 110v secondary? or is your secondary 220v ?

2- Try putting a 2.2 uF / 400V at the secondary of the transformer.

alex young (author)2013-06-03

hello Nickk could u kindly help me here thank u

alex young (author)2013-05-22

hello nick just to make sure I am right the output of this inverter becomes sine wave also using ur power stage being driven with a sinewave inverter Thanks for ur support

alex young (author)2013-05-18

ok thank you Nickk i really appreciate this info maybe thats why my volts on the AC side drops off I will change this on monday and tell u and the other guys the result. Thank u

alex young (author)2013-05-18

Thank you Nickk for your usual support as i said before this is the best support inverter forum on the internet I am proud of you please keep up the good work world wide u have helped many to light up their homes. I dont have a camera to send a photo at this time.As I said I have 1k in series with the gate and I am using 12 irf260 so i have 5v on the gates Please tell me how much volts should i have on the gates of the fets so I can adjust that volt. Thank u

Nick_Zouein (author)alex young2013-05-18

there should be between 8 to 12v on the gates so the fets conduct fully.

renkaimo (author)2013-05-06

Hi Nick,
For a 10,000W output, will I need 108x 2N3773 (two times more than the 2N6277) and a larger transformer (what kind of transformer would I need)? and is that all i'll need? Also I have two silly questions, sorry. (1) The two diode signs in your diagram on the 84-0-84/220V, are those the same two diodes (in4007) near the other transformer? or is it just something that comes with the transformer? (2) I'm looking at the data sheet for the 2N6277 and 2N3773, I cant seem to find any number where it's half, or double of the other. Could you please help me understand this? I see 50A, 250W, 150V for the 2N6277 and I see 16A 140V, 150W for 2N3773. I just would like to clearly understand so I dont buy more than I need.
Thanks so much for your help, this is am amazing instructable! :)

Nick_Zouein (author)renkaimo2013-05-17

Going over 5000w is impractical, that's why all my designs do not exceed the 5250w limit, you'll need a DC voltage like 168vdc (14 x 12v batteries) and you'll have to use IGBT's, a totaly different design.

1)No they are not the same neither they come with a transformer.

2) the 2N6277 can handle 250w while the 2n3773 is 150w.
ex: for a 1000w inverter if u use the 6277 you'll need 4 on each side while if you use 3773 it will be 7

Excuse me to say but you don't seem to have enough knowledge to make such a project, I don't suggest you go any further because this envolves high dangerous lethal voltages. 

alex young (author)2013-05-16

Thank you Nickk for your reply because i was feeling so disappointed when i did not hear from you in a while. it is a 120v design when i check the 12v ac with or without load it is the same because i am still having about 5v on the gate of the fets with or without load.the power stage is the same stage of my 1500 watt inverter that works well. I have 1k in series with the gate of the fets and 10k to ground The Ac output voltage will fall from about 120v to 100v with a load of 60watts which is my solder iron. please help me here Nickk I am depending on you. Thank you

Nick_Zouein (author)alex young2013-05-17

why 5v on the gates? isn't your trans 12-0-12?

alex young (author)2013-05-17

hello Teacher I await your support on the voltage drop problem. Thank u

Nick_Zouein (author)alex young2013-05-17

strange why it is dropping, it should not drop. send some pics to see what you're doing.

alex young (author)2013-05-14

Hello Nickk I built ur design but I am having some problem with it. I am having a voltage drop in the AC voltage .on the output of my power stage.The ac voltage from the small inverter is stable and do not fall off but the main output does please tell me what to do. Thank u

Nick_Zouein (author)alex young2013-05-15

it should be 220v, how much is it falling? with or without load? when it falls how much is the voltage reading on the 12-0-12 trans?

alex young (author)2013-05-13

hello Teacher Nickk can this circuit be used with fets could u please tell us the modification. Thank u keep the great work going

sandy143in (author)2013-04-07

Hello Nick,

Its a very nice work and has turned down the option of buying Xantrex Pure Sine wave power Inverter. I am novice to this field but willing to make one to run my Air Conditioner.  I would be thankful if you please answer to my questions below:

1) What would be its efficiency?
2) How much surge power a 5000 watt inverter will withstand?
3) What precautions are to be taken for input DC supply from my solar panels to the inverter?

Please suggest modifications, if any.


pierelectrik (author)2013-03-26

I wish you can Whatsapp or Viber for I'm a little lost 70907733, I was asking you about the 300w pure sine wave

pierelectrik (author)2013-03-25

HI Nick,
I live in Ehden, but I beleive it's quite expensive as I can buy full UPS pure sine wave 1KVA with smart charger that can handle up to 200amps battery for 140US$, I'm gonna try to build the 300w pure sine wave board you've listed wish me luck, thx though for your kindness, and if you like whatsapp or viber 70907733, stay in touch.

About This Instructable




More by Nick_Zouein:Aux Input for BMW 325i Business CDAdaptable 12vDC/220vAC Pure Sinewave InverterTransforming a 300W Sinewave DC/AC mini inverter to a 5000W monster
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