# Inverter help

#### Tarikul

Joined Nov 22, 2019
3
I would like an inverter circuit diagram. This circuit will have charging, current control, battery low cut and high cut. Inverter output can be controlled.

#### Audioguru again

Joined Oct 21, 2019
258
Your request has absolutely no important details.

You forgot to say the input and output voltages and maximum output current. My solar garden lights use a 1.2V AAA battery cell to drive an inverter that produces about 3V at 5mA to light a white LED. Do you want an output higher than 3V at 5mA?
What input battery voltage will you use?

You also forgot to say if the waveform must be a sinewave or if a modified sinewave or a squarewave is acceptable.
Electricity in your home is a 50Hz or 60Hz sinewave.
My solar garden lights produce a squarewave at about 80kHz. What frequency do you want?

What output do you want to control? The output voltage? Usually an inverter must have a regulated output voltage like 120VAC or 240VAC.

#### Tarikul

Joined Nov 22, 2019
3
Your request has absolutely no important details.

You forgot to say the input and output voltages and maximum output current. My solar garden lights use a 1.2V AAA battery cell to drive an inverter that produces about 3V at 5mA to light a white LED. Do you want an output higher than 3V at 5mA?
What input battery voltage will you use?

You also forgot to say if the waveform must be a sinewave or if a modified sinewave or a squarewave is acceptable.
Electricity in your home is a 50Hz or 60Hz sinewave.
My solar garden lights produce a squarewave at about 80kHz. What frequency do you want?

What output do you want to control? The output voltage? Usually an inverter must have a regulated output voltage like 120VAC or 240VAC.
Inverter input volt is 12 and the output volt is 230/240v. It will be the Modified Square Wave. When the current arrives, the battery will be charge by 10,15,20 as i wish to set. Current and voltages can be controlled. Overload protection, low battery protection, thank you

#### Tarikul

Joined Nov 22, 2019
3
Why did they give it? I didn't want that. I wanted a design that could make the inverter myself.
Here is the electronic instruction of my inverter. You can have a look. I hope that can help you.

#### shortbus

Joined Sep 30, 2009
7,073

#### MisterBill2

Joined Jan 23, 2018
4,033
An inverter with a built in switchover to charging circuit was one of those in the "schematics for free website, and there are LOTS of others. A web search will produce a few thousand hits, of which maybe 100 will be useful, while 750 or so will want to sell you one of them, even if they have no clue about what it may be. And the functions that you specify add a fair amount of complexity. But check the site I listed, it will take a bit of clicking but they have a lot of circuits.
And while you want to build it your self, with those features it will be a very big task.

Joined Feb 20, 2016
3,071
My opinion is that if you have to ask for a circuit, this project is well above your capability. And you would be dealing with deadly power levels. As you do not appear to know what you are doing, it would be quite dangerous and irresponsible for you to proceed. And I
am sure you can buy one ready made cheaper than you can build one of any quality anyway.

#### MisterBill2

Joined Jan 23, 2018
4,033
My opinion is that if you have to ask for a circuit, this project is well above your capability. And you would be dealing with deadly power levels. As you do not appear to know what you are doing, it would be quite dangerous and irresponsible for you to proceed. And I
am sure you can buy one ready made cheaper than you can build one of any quality anyway.
The panic-level fear of shocks is not appropriate because it is simple enough to be adequately careful to avoid all shock problems. The safety regulations promoted to protect drunks bent on self destruction is way extreme. It is fundamental that an individual is the one responsible for the results of their actions. Working on any circuit, including 3 volt logic, always requires focus, attention, and understanding of what one is working with. Fear is not a suitable part of the situation. Understanding of what one is doing is always the needed element. That holds true in all situations.
Building a power inverter to produce mains-level voltages certainly requires an understanding of what voltages are present and how to work with them, but blind fear is not what is needed. Attention to what one is doing is what works.

#### SteveSh

Joined Nov 5, 2019
92
Why don't
Why did they give it? I didn't want that. I wanted a design that could make the inverter myself.
From the details you provided, which is not very much, why don't you just buy a commercial 12V to 115 VAC inverter that's designed for a car, truck, or boat?

Joined Feb 20, 2016
3,071
I do not intend to dwell on "fear". But this project is not one for a novice to attempt. Start with something easier, and safer.
High voltage generation of sufficient power levels to be deadly requires care and the builder needs to be very aware that they are dealing with a dangerous device. I do not see a very large difference between something that can generate lethal voltages from a low voltage input and others directly connected to the mains. Direct mains connected devices are blocked in discussion on this site, and I think for good reason. Similarly, I feel it is my duty to advise novices against attempting to build something that can easily kill themselves, or some other folk.
The TS's question sounds novice to me. That is why my answer is as above. To do otherwise I think is shirking my responsibility.
But, if they can build it successfully, without injury, then, good on 'em!

#### Alec_t

Joined Sep 17, 2013
10,446
If you are going to use the inverter just for charging batteries up to 20V, why do you need one with a 230/240V output?

Joined Feb 20, 2016
3,071
Our friends were burnt out a couple of years ago. They drove out through the flames, not even having time to untie their dog. They were lucky to survive. Their house, shearing shed, tractors and cars and sheep were all lost.
I gave them my caravan to set up on their farm so they would have a base to work from.
Also, a couple of 12V batteries, solar panels and an inverter.....
https://www.ebay.com.au/itm/HSE-3000w-24V-230vac-Solar-Inverter-50A-solar-charger-battery-charger-25A/131094766150?epid=16026506924&hash=item1e85db6246:g:qwsAAOSwYBtbGQFr
This inverter can charge the batteries from solar panels or from mains. In their case, a petrol generator set, as they no longer have the mains power connected to the farm.
This may be what the TS needs. I could not build one for anywhere near this price.
Note: The price on this Ebay add is in $AU. And there are cheaper stores than this one. You can get one for around$250 US.

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#### MisterBill2

Joined Jan 23, 2018
4,033
I do not intend to dwell on "fear". But this project is not one for a novice to attempt. Start with something easier, and safer.
High voltage generation of sufficient power levels to be deadly requires care and the builder needs to be very aware that they are dealing with a dangerous device. I do not see a very large difference between something that can generate lethal voltages from a low voltage input and others directly connected to the mains. Direct mains connected devices are blocked in discussion on this site, and I think for good reason. Similarly, I feel it is my duty to advise novices against attempting to build something that can easily kill themselves, or some other folk.
The TS's question sounds novice to me. That is why my answer is as above. To do otherwise I think is shirking my responsibility.
But, if they can build it successfully, without injury, then, good on 'em!
Certainly the initial question seems rather "novice", and certainly a whole lot of details were missing, and it is indeed true that a good amount of caution is in order for working with the higher secondary voltages of an inverter of this kind. But the comments came across to me as being fear mongering. My very first experimenting with electrical circuits was with mains powered industrial surplus relays, all open 120 volt wiring. The caution was to always unplug it before working on it and hat worked well. I was almost ten years old at the time, and while other kids were breaking their toys I was building electrical things and noise makers. Not very practical but quite entertaining for a kid. And did not get zapped.

Joined Feb 20, 2016
3,071
Yes indeed. My first electronic play things were valve (tube) radios, and running on 240VAC here in Oz. Does anyone remember the 80 rectifiers and 6V6 amps?
But I still need to stress caution to novices. There are quite a few very dangerous practices done by those with no clue. Like a guy here some years ago who ran a 240V active wire around his fish pond to keep stray cats away. I think he ended up killing a child.
Stupid things do happen.

#### SteveSh

Joined Nov 5, 2019
92
But I still need to stress caution to novices. There are quite a few very dangerous practices done by those with no clue. Like a guy here some years ago who ran a 240V active wire around his fish pond to keep stray cats away. I think he ended up killing a child.
Stupid things do happen.
Even those of us who have been around electronics for many years need to keep that advice in mind. I know I've picked a lot of "bad" habits over the years working almost exclusively with 5V and lower logic systems, and occasionally 28VDC power supplies, and have to consciously think about where to rest my free hand when working with potentially lethal voltages.

#### MisterBill2

Joined Jan 23, 2018
4,033
Those inverters listed on ebay are listed as "pure sine wave", and also are all for 24 volt battery systems, and really do not sound like what the TS is seeking. and while I am not current on the AU dollar versus US dollar conversion rate those prices do not seem reasonable for the claimed performance. Unfortunately for the TS, designs for complete systems are seldom totally complete, and most of the products now available include proprietary logic ICs that are not available outside of completed assemblies. In addition, creating the power transformer is a big deal all in itself. That would tend to be the show-stopper even if a suitable circuit was found.

#### shortbus

Joined Sep 30, 2009
7,073
And it's almost a given that both the 12V and 24V use the board that I linked to earlier. If not the board itself, at least the main chip on a board made by the inverter company.

#### djsfantasi

Joined Apr 11, 2010
5,693
Annnnddd the TS last posted a week ago and 14 posts ago. I think we’ve either scared him away or convinced him that we’re useless!

#### MisterBill2

Joined Jan 23, 2018
4,033
Annnnddd the TS last posted a week ago and 14 posts ago. I think we’ve either scared him away or convinced him that we’re useless!
I did see that nobody posted the design that was requested, although I did give the name of a website that has such circuits. But it was only a site name, not a link to the specific drawing. I believe, based on the first response from the TS that they were rather disappointed that such a design was not immediately provided. Of course, the one question that I posted was not really answered, either.