• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

making a 12v to 240v power inverter

Status
Not open for further replies.

jahan002

New Member
first of all i will like o that this my first post and that i am a novice when it comes to electronic.

I purchased a solar panel which as the following spec:
Optimum working voltage of :- 17.5V
Optimum working current of:- 260mA
Peak power output:- 4.8W

I want create an inverter that will convert the power from the solar into 240V
i have a UPS which i can get some hardware from. thanks in advance.
 

audioguru

Well-Known Member
Most Helpful Member
Its very low power can charge a battery that will blink a 10W light bulb one time each week.
 

mneary

New Member
After a sunny 8-hour day of charging you will be lucky to get 15 minutes of laptop usage.
 

SPDCHK

Member
Laptops consume in the region of 50W PLUS power.

Power Out = Power In - Losses.

You will need at the least 10 times the panels you’ve mentioned.

And remember, even though sunlight is for free, everything else will come at a cost. I don't have the correct figures, but I do not believe (unless it's a unit designed by someone like TCMTECH), that you will get efficiency of greater that 60% from a home made inverter, so that will make the count of 10 times panels also not enough.

4.5W will be enough to power a LED flash light though. :D
 
Last edited:

tcmtech

Banned
Most Helpful Member
I'd say your about right on the 60% efficiency range.
If you were to use modern schematics and good modern day parts with designs based on actual data sheet information related to those parts, A low frequency iron core transformer based inverter could conceivably hit 85% efficiency.
But you would need a good quality transformer that has an honest 90% or higher efficiency. And still that would require the control circuits and switching devices to stay under 5% total loss.
I honestly could not guarantee that number either (and make an actual clean sine wave any way)!
75 -80% would be more realistic.
The low end non sine wave HF inverters run about 85% on average and the good high efficiency ones do have ratings above 90% now.

But given the tiny solar panels actual output I would still agree with everyone else and charge a battery with it and use the accumulated power.
 
Last edited:

tcmtech

Banned
Most Helpful Member
I rethought it and at that low of available power I doubt you could even hit much higher than 35% efficiency realistically.
The control circuit and switching devices would consume about 1.5 watts. The step up transformer (iron Core wall power pack type) at that small of size is going to be at best 50% efficient.
Given 4.8 - 1.5 = 3.3 3.3 * 50% = 1.65 watts. 1.65/4.8 = 34% efficiency.:(

1.65 watts at 240 volts is around .0069 amps! You might run a mini neon indicator light to tell you your inverter is on but then you would have no power left to work with! :p

Maybe make up a set of mini padles and use it to restart a hampsters heart! or electrocute some bugs! :D

Sorry to rain on your parade. At least now you have some idea of what your working with!

However with 4.8 watts available at 17.5 volts or less you have loads of small electronic devices you could build or power with it! :)
 

Thunderchild

New Member
i am looking forward to powering my laptop with it.
good luck, I have 2 X 20 W panels and I make enough iin a day to run one LCD computer monitor. if your going to run a laptop off it why not get a laptop power supply for use in a car so that it takes the power straight from the battery. you are proposing to charge a car battery and in this process not all of the power will result in a charged battery, then you are going to conver the 12 V DC to 240 V AC and in this process you will loose 10-15 % of the power, you will then reconvert 240 V AC down to the laptops voltage at DC and loose a further 15 % so by the time you finish you have about 75 % of what you started with. whereas if you directly use the battery to power a laptop power supply you cut out one stage and recover more power.
 

electronrancher

New Member
A laptop input is only 14-20v DC. So to convert your DC to 240v AC and back again is a big waste.

I'd suggest using a buck-boost DC-DC converter to convert that varying DC panel voltage into a fixed 19v (for example) to charge your laptop. You should get 85% at very worst case.
 
Last edited:

mneary

New Member
I'd suggest using a buck-boost DC-DC converter to convert that varying DC panel voltage into a fixed 19v (for example) to charge your laptop. You should get 85% at very worst case.
Search eBay using keywords auto laptop power and you will see about 131 hits which offer devices of this kind, starting at about US$18. I bought one and I'm extremely happy with it.

Or you could design and build one.
 

Hero999

Banned
A single 12V panel will probably be able to charge three 6V SLAs in series.

The 12V panels I have put out 26V each and their maximum power rating is taken at 17.5V.
 

Thunderchild

New Member
The 12V panels I have put out 26V each and their maximum power rating is taken at 17.5V.
in which case they can't charge 18 volts of battery as you need 20-21 volts and you have maximum output at 17.5 volts best thing is use 12 volts and a chargin regulator
 
Status
Not open for further replies.

EE World Online Articles

Loading
Top