An inverter from a 12v batt to 120v portable power

[huricaine]

I live in America where AC mains is 60hz, 120v.

I work at an industrial production plant where I push my tools around on a push cart.

I have a small 12v battery the size if a scooter battery which is strong enough to start a car.

I want to create an "inverter" circuit to give me 120v from the batt.

What I need help on: I need to choose an oscillator circuit/IC to create the 60hz ac signal. From there I can either boost the voltage with a discreet voltage amplifier and also a current buffer for power transformation. Or I can use a transformer for the voltage AND current amplification which would be so much easier but I think I may want to make it smaller with an SMPS power supply to boost voltage then a parallel transistor current amp(voltage follower).

What do you all think and can you help me on designing any of it? The oscillator can be very simple.

 

[blueroomelectronics]

Cheaper to buy than build. You can buy them pretty much anywhere in North America.

 

[MikeMl]

Cheaper to buy than build. You can buy them pretty much anywhere in North America.

e.g. Amazon

 

[huricaine]

Well yesterday I bought an 800VA transformer that will step up 12 to 120v. I got it for $80.

Then I plan on making a simple wein bridge oscillator and driving a voltage follower(pushpull) to buffer the oscillator signal going to the transformer primary. Should be simple. I have all the parts I need and I will be able to produce a decent amount of power.

 

[huricaine]

Shoot I just remembered, with 12v from a battery I will only be able to swing about 5v RMS...The transformers I use always amplify a bit more but I'd need to swing as close to rail as possible so maybe I should use a rail to rail opamp in my oscillator

 

[alec_t]

800VA/12V = 66A. That's going to be one helluva voltage follower .

 

[huricaine]

800VA/12V = 66A. That's going to be one helluva voltage follower .

Yea 60 -80A I have many large transistors....I deal with caraudio amplifiers that draw upto 200 - 300A...I need to use them in parallel.

About the voltage, I have 4 12v output on the transformer that I was going to put in parallel but instead I can place two sets in series for twice the step up so 5vrms x 10x step up is 50v when doubled will be 100v but like I said these trannies produce more voltage step up then they are rated.

 

[huricaine]

800VA/12V = 66A. That's going to be one helluva voltage follower .

Yea 60 -80A I have many large transistors....I deal with caraudio amplifiers that draw upto 200 - 300A...I need to use them in parallel.

About the voltage, I have 4 12v output on the transformer that I was going to put in parallel but instead I can place two sets in series for twice the step up so 5vrms x 10x step up is 50v when doubled will be 100v but like I said these trannies produce more voltage step up then they are rated.

 

[Reloadron]

Well if you are anywhere near NE Ohio (Cleveland) just come on over and I'll give you a pile of UPS inverters. 800 watts to 1.5 KW and some smaller. Keep in mind that many of these devices do not output a 60 Hz sine wave but a modified sine wave. Just scroll down to "Do I need Modified Sine Wave, or Pure Sine Wave"? Also you need to consider that an 800 watt inverter when powered by 12 volts under a full load will draw over 66 Amps and after efficiency is figured in over likely 70 Amps so I hope you have a real big battery. Heck, could have saved you the $80 you spent on a transformer as all the units I mentioned have transformers.

Ron

 

[huricaine]

I live in California. It sounds like a good idea to buy one or get one already made like everyone suggest(car inverters are perfect and use smps!) however I wanted build one myself...

As far as battery capacity issues, I also want to implement a smart charger built in so I can charge it whenever I'm near an outlet. Light loads of a few amps won't drain it too quickly.

 

[Reloadron]

I live in California. It sounds like a good idea to buy one or get one already made like everyone suggest(car inverters are perfect and use smps!) however I wanted build one myself...

As far as battery capacity issues, I also want to implement a smart charger built in so I can charge it whenever I'm near an outlet. Light loads of a few amps won't drain it too quickly.

While I can appreciate the enthusiasm, believe me these are one of those things that are better bought than built. The basic inverters made for automotive use are really a good deal overall.

Ron

 

[ChrisP58]

Yea 60 -80A I have many large transistors....I deal with caraudio amplifiers that draw upto 200 - 300A...I need to use them in parallel.

About the voltage, I have 4 12v output on the transformer that I was going to put in parallel but instead I can place two sets in series for twice the step up so 5vrms x 10x step up is 50v when doubled will be 100v but like I said these trannies produce more voltage step up then they are rated.

Putting two 12V windings in series (making a 24V winding) will produce half the step-up, not twice.

 

[tcmtech]

Well yesterday I bought an 800VA transformer that will step up 12 to 120v. I got it for $80.

Well unfortunately now a days for half that price you could have bought a name brand 1 KW+ power inverter and been done with it.

Shoot I just remembered, with 12v from a battery I will only be able to swing about 5v RMS..

What?

 

[huricaine]

Putting two 12V windings in series (making a 24V winding) will produce half the step-up, not twice.

Oops that's right I wasn't thinking properly.