Inverter

Thor

Thor

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Hey.

I am such a noob when it comes to this inverter stuff...

Can someone explain to me why the one would be better than the other one and why? ( Going by price, I assume the 300watt is better than the 1200watt? but why? )

1200watt inverter @ R550 ( Link Here - pricecheck website )

300watt inverter @ R569 ( Link Here - Also pricecheck website )

========

Basically I have a few 12volt 7Ah batteries also 2 x 12volt 105Ah batteries.

I want to run a few things like 1 router, a few led strips ( 1m x 4 ) thats about it.

Might add more small electronics like chargers for the cellphone
 
The 1200w inverter is modified sine wave, the 300w is pure sine wave. Electronics prefer pure sine wave outputs, but most do fine on modified sine wave. You want to use deep cycle batteries if possible. Calculate your total requirements in watts, then buy an inverter that'll handle it. Divide your total watts by 10 to get a rough current draw at 12v to roughly calculate your battery requirements

e.g 350watts / 10 = 35 amps

35 amps being drawn for 4 hours will be 140ah which is your minimum combined battery requirements
Remember batteries are rated according to a 20 hour discharge and their actual capacity will decrease if the discharge rate is higher

EDIT: Never completely discharge a battery, and unless you are using a pure deep cycle, avoid dropping its capacity below 40% (True deep cycle batteries at 105ah often start at R5k+, most "deep cycle" batteries at +- R2k are actually semi-deep cycles) Deltek is an awesome brand

This is what I remember off the top of my head so I'm open to corrections wrt the calculations

Anyway, here is a graph showing the square wave (don't ever use these inverters) compared to a modified sine wave, compared to a pure sine wave

Inverter_Wave_Comp.jpeg
 
Last edited:
Wow that makes a lot of sense now, finally grasping this sine wave thing!!
 
Soooo..... If I want to make my own sine wave Inverter ...


Anyone have a schema of the components etc, I have few breadboards lying around...

If I have a modified sinewave, can I add capacitors to "lessen" the voltage variations?
 
savage said:
*slaps forehead* NO, but good luck! :sick:
Click to expand...

I've made AC to DC modules before, can't be that hard if one has a well documented schema to work from.

I'm not THAT a noob when it comes to electronics, still a noob no doubt, but not THAT much.
 
Thor187 said:
Soooo..... If I want to make my own sine wave Inverter ...


Anyone have a schema of the components etc, I have few breadboards lying around...

If I have a modified sinewave, can I add capacitors to "lessen" the voltage variations?
Click to expand...

Im interested...can you convert modified sine wave to pure sine wave using some kind of converter, do they exist? Im in the same boat, was given a nice modified sine inverter...stuff is buzzing and freaking me out lol
 
Thor187 said:
I've made AC to DC modules before, can't be that hard if one has a well documented schema to work from.

I'm not THAT a noob when it comes to electronics, still a noob no doubt, but not THAT much.
Click to expand...

Good luck with that one smoothing AC to DC is a different ball game to DC to AC , will be interested to know how you get on with this one .
 
eddief1 said:
Im interested...can you convert modified sine wave to pure sine wave using some kind of converter, do they exist? Im in the same boat, was given a nice modified sine inverter...stuff is buzzing and freaking me out lol
Click to expand...

IMO it would be cheaper just to buy a pure sine wave inverter than try to smooth the wave .
Transformers cost money especially large ones , and that is what you would need to smooth the wave 1 to 1 .
 
FNfal said:
Good luck with that one smoothing AC to DC is a different ball game to DC to AC , will be interested to know how you get on with this one .
Click to expand...

I will show you what I have in mind in a short while. When I wake up.

FNfal said:
IMO it would be cheaper just to buy a pure sine wave inverter than try to smooth the wave .
Transformers cost money especially large ones , and that is what you would need to smooth the wave 1 to 1 .
Click to expand...

I actually went and had a look. It's going to work out a lot cheaper to build your own pure sine wave Inverter than to buy one.
 
Thor187 said:
I actually went and had a look. It's going to work out a lot cheaper to build your own pure sine wave Inverter than to buy one.
Click to expand...

This gunna be good... I think that's all I should say, anything else will just get nasty
 
Archer said:
This gunna be good... I think that's all I should say, anything else will just get nasty
Click to expand...
Hehe yeah.
Just converting the DC to ac is one thing. Not even starting to take into account safety measures, protections etc...
 
While I dont specialise in electronics in my line of work, it is what I studied and I still have a very good understanding of what is going on. Half the schematics you find on the net couldn't power a single lightbulb (well they could, just before they melted), nevermind do it with upwards of 90% efficiency, and they don't even get close to pure sinewave either. And they have no safety at all. So it is not doubt, it is being realistic.

And if you magically get all that right (which takes a team of engineers a long time to do) how can you possibly compete with the economies of scale they have?
 
Thor187 said:
Soooo..... If I want to make my own sine wave Inverter ...


Anyone have a schema of the components etc, I have few breadboards lying around...

If I have a modified sinewave, can I add capacitors to "lessen" the voltage variations?
Click to expand...

Here you go

This guys is quite good Swagatam Majumdar. He answers all questions on the forum.

Pure Sine Wave Inverter Circuit
http://4.bp.blogspot.com/-Y2aIrZuga...ave+inverter+with+auto+correction+circuit.png

How to Make a 500 VA PWM Controlled Modified Sine Wave Inverter Circuit
http://1.bp.blogspot.com/-bzxgR31Pa.../500+watt+pure+sine+wave+inverter+circuit.png
http://www.homemade-circuits.com/2012/02/how-to-make-500-va-pwm-controlled.html

How to Build an Automatic 6 volt, 12 volt, 24 volt Lead Acid Battery Charger Circuit
http://www.homemade-circuits.com/2012/02/how-to-build-automatic-6-volt-12-volt.html
http://3.bp.blogspot.com/-QL6-kDaGM...RDdWl-8/s1600/24v+battery+charger+circuit.png
 
I saw that website. I asked someone I know who is alot more clued up than I am when it comes to the individual components to give me some guidance.

Will report back if I eventually try this.
 
Archer said:
While I dont specialise in electronics in my line of work, it is what I studied and I still have a very good understanding of what is going on. Half the schematics you find on the net couldn't power a single lightbulb (well they could, just before they melted), nevermind do it with upwards of 90% efficiency, and they don't even get close to pure sinewave either. And they have no safety at all. So it is not doubt, it is being realistic.

And if you magically get all that right (which takes a team of engineers a long time to do) how can you possibly compete with the economies of scale they have?
Click to expand...

Get the right components, get the right schematics, solder the shiat together.

No need to over complicate, I'm not trying to compete, all I want is to see if I can make my own system to my own taste.

Assembling the actual thing is not my problem I do this has a hobby mostly, I have a nice PCB board making station going so I can make my own boards etc.

All I don't have is the experienced knowledge to know what components to use and why.

So that is why I am scouting to see of I can find a decent schematic which will include the layout I need to create on the PCB board etc. Then I start soldering.
 
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