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General => Chatter => Topic started by: Rotary-Motion on November 19, 2012, 09:38:41 PM

Title: 12 volt to 240v invertor
Post by: Rotary-Motion on November 19, 2012, 09:38:41 PM
any body selling one of these, i want one...

thx
Title: Re: 12 volt to 240v invertor
Post by: nigelb on November 19, 2012, 09:54:35 PM
I bought a 1000W inverter from the bay a few years back. Well useful it is. There are limitations with them as most use a modified sine wave system to invert the current. If you can...try and find an ambulance being broken for spares. The inverters they have provide a true 240V as they power medical equipment. Modified sine waves are not approved for such things.

Nige
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 19, 2012, 10:18:13 PM
ambulance one i found was 110volts

if it says pure sine wave is this good?

also this one doesnt say pure sine wave but has 2 sockets? anyone know what the writting is?

(http://images.maplin.co.uk/300/a12hq_closeup.jpg)
Title: Re: 12 volt to 240v invertor
Post by: 1958steveflying on November 19, 2012, 10:18:48 PM
I bought a 1000W inverter from the bay a few years back. Well useful it is. There are limitations with them as most use a modified sine wave system to invert the current. If you can...try and find an ambulance being broken for spares. The inverters they have provide a true 240V as they power medical equipment. Modified sine waves are not approved for such things.

Nige

Yes check out that what you want to run from it will run from Modified sine wave if you decide to buy the cheaper option of the 2, true sine wave are many times more expensive.
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 19, 2012, 10:22:52 PM
ok im lost?

modified wave

pure sine wave

and

true sine wave

which out the 3 runs most things?
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 19, 2012, 10:24:28 PM
was looking at this one...

http://www.maplin.co.uk/pure-sine-wave-600w-12v-inverter-261496

(http://images.maplin.co.uk/300/a27jg.jpg)
Title: Re: 12 volt to 240v invertor
Post by: RobPerrie on November 20, 2012, 09:23:29 AM
i got that one above, tough unit, only used it for baby milk bottle warmer on a trip to malaga and back in the truck...

no problems with it,
Title: Re: 12 volt to 240v invertor
Post by: 1958steveflying on November 20, 2012, 09:30:52 AM
was looking at this one...

http://www.maplin.co.uk/pure-sine-wave-600w-12v-inverter-261496

(http://images.maplin.co.uk/300/a27jg.jpg)

What are you planning to run from it ?
Title: Re: 12 volt to 240v invertor
Post by: julianf on November 20, 2012, 09:59:05 AM
as above, if you dont need the pure sine wave, then, unless it does not cost any more, you could probably do without it.

Laptops etc all have their own switch mode supplies, which can probably handle most stuff.  Heaters wont care at all.  Pumps, if the way PWM controllers are anything to go by, wont care.

...indeed, im not actually sure what you could use with a car that does need a clean wave form?
Title: Re: 12 volt to 240v invertor
Post by: K.H on November 20, 2012, 10:39:09 AM
Fatboy has got a 350 one he would flog
Title: Re: 12 volt to 240v invertor
Post by: photoman290 on November 20, 2012, 01:52:54 PM
modified sine wave or MSW for short are fine for most things except motors . they wont work with things like fridge compressors. i had a 1000 watt one for years till i plugged in a shorted soldering iron and killed it. i now have a 300 watt one which works fine. takes a few flickers of the lights  when i plug the laptop and satellite  in but otherwise it is fine. you can find the 1000 watt ones on ebay for about £85 to £130.
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 20, 2012, 07:25:49 PM
it will maybe be running an LED LCD HDTV, they dont like spiking.... aswell as laptop maybe.

========================================================

Do I need Modified Sine Wave, or Pure Sine Wave?

Advantages of Pure Sine Wave inverters over modified sine wave inverters:

a) Output voltage wave form is pure sine wave with very low harmonic distortion and clean power like utility-supplied electricity.

b) Inductive loads like microwave ovens and motors run faster, quieter and cooler.

c) Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.

d) Prevents crashes in computers, weird print out, and glitches and noise in monitors.

e) Reliably powers the following devices that will normally not work with modified sine wave inverters:

Laser printers, photocopiers, magneto-optical hard drives
Certain laptop computers (you should check with your manufacturer)
Some fluorescent lights with electronic ballasts
Power tools employing "solid state" power or variable speed control
Some battery chargers for cordless tools
Some new furnaces and pellet stoves with microprocessor control
Digital clocks with radios
Sewing machines with speed/microprocessor control
X-10 home automation system
Medical equipment such as oxygen concentrators
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 20, 2012, 07:39:03 PM
Fatboy has got a 350 one he would flog

is it pure sine wave kieth?
Title: Re: 12 volt to 240v invertor
Post by: K.H on November 20, 2012, 08:29:55 PM
TBH i havent a clue,its in his car anyway i think,so have a look when your in,or bring something you want to use on it and test it?
I dont even know what the 1000w one i got is wave wise
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 20, 2012, 08:33:27 PM
TBH i havent a clue,its in his car anyway i think,so have a look when your in,or bring something you want to use on it and test it?
I dont even know what the 1000w one i got is wave wise

good ol amazon has a 1000w pure sine wave for £157 which is good and i may go for...
Title: Re: 12 volt to 240v invertor
Post by: photoman290 on November 21, 2012, 01:39:02 AM
if the tv has a switch mode power supply it will be fine on a MSW one. the sine wave ones are not as efficient as the MSW ones.
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 21, 2012, 06:42:37 AM
i will check that switch after i buy one...

so a pure sine wave is a much steady voltage and will run any delicate instrument but a modified sine is more efficient? how do you mean it uses less 12v power? is there much difference PM?
Title: Re: 12 volt to 240v invertor
Post by: photoman290 on November 21, 2012, 12:07:16 PM
the battery will go flat quicker with a sinewave  one. if you are going to use it at full power on 12 volts it will be drawing 82 amps at  1000watts. volts x amps = watts that means big cables. and a flat car battery in about 1/2 hour if you use it at full power.
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 22, 2012, 06:06:31 AM
how many watts in 1 amp, maybe easyer to work out potential load...

goodle is giving me mixed results

http://answers.yahoo.com/question/index?qid=1006041612376

i was lost when i got here:

Watts = Amps X Volts. You need to know the voltage drop across the resistance.
 Volts = Amps X Resistance to find the voltage

then read this:

http://answers.yahoo.com/question/index?qid=20090814130822AAamid4

and now no idea, i think just buy one and chuck it all on and see...

and this page says:

http://www.powerstream.com/Amps-Watts.htm#watts-amps

so say 600 watts x 12volts = 7200 amps?
Title: Re: 12 volt to 240v invertor
Post by: Chug on November 22, 2012, 10:22:40 AM
I blew two inverters up in one day in my motorhome, first I spilt tea over my 1000w 24v one fizz pop dead!

So I then dug out my old 12v 300w one and used that until the leisure batteries started dying, and wouldn't give 12v anymore then I wired it across the terminals as you would for 24v and got 14v great it worked again..

Later I started the engine and heard the 12v inverter (now getting 24V, or more like 26-28V) start hissing and saw it smoking... then dead DOH!
Title: Re: 12 volt to 240v invertor
Post by: Bio Dervotee on November 22, 2012, 01:08:41 PM
Hi, RM,JH, einstein lol
amps = watts divided by voltage, so 600 watts is 50 amps@12volt
r=voltage divided by current,    so 60 watt headlamp at 12volts uses 5 amps , resistance would be 2.4 ohms
If you know any two, you can work out the other two.
Resistance = voltage divided by current
voltage = current x resistance
current = voltage divided by resistance
watts = voltage x current
hope this helps
Will
ps         E=MC squared
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 25, 2012, 09:03:57 PM
i got a fridge thats 85 watts how long would a 100AH leisure battery last?
Title: Re: 12 volt to 240v invertor
Post by: photoman290 on November 25, 2012, 09:31:47 PM
not very long on a small MSW inverter. is it 240 volts or is it a  multipower one with 240 12v or gas ? if it is 12v you dont need an inverter. if it has a compressor you need an inverter at least 10 times the current rating
or it will either not start or kill the inverter.  so a 1kw one at least. even then make sure you can return it when the smoke comes out.
7 amps in answer to the question but taking losses into account nearer 9 amps  so if you go to 50% of the battery capacity that is about 7 hours. but you will kill the battery very quickly if you do that too often.  4 hours would be kinder to the battery. fridges are the worse thing to try and run off a battery. i have a gas one. that costs about £5 a week in gas. if you are thinking of using it to keep your beer cool on trips the best thing is to  fill the home freezer with cool packs and use them.
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 25, 2012, 09:32:31 PM
12v 85 watts
Title: Re: 12 volt to 240v invertor
Post by: K.H on November 25, 2012, 09:38:05 PM
Dont kill my inverter! ;D
Title: Re: 12 volt to 240v invertor
Post by: photoman290 on November 25, 2012, 09:44:34 PM
Dont kill my inverter! ;D

 just clean all the melted plastic up and  blow the burnt smell out with a hoover. he wont even notice. 8)
Title: Re: 12 volt to 240v invertor
Post by: Rotary-Motion on November 25, 2012, 09:45:45 PM
its not 240v shame  ::)