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albertok
New Member
3 Posts |
 Posted - Jul 07 2009 : 11:05:14 AM
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quote:
Originally posted by audioguru
3000W is way too much for an inverter. If you use only 12V then its battery current will be 300A!
You would need to have a large room full of batteries to power it for a short time. Then it will take 1 week the charge the batteries.
Its wiring must be huge and it would need 48 output transistors and many driver transistors.
Its transformer would cost a fortune.
Why do you keep saying that it's not possible to make an 12V 3000W inverter? And that you would need a room full of batteries?? It simply is not true and you know it.
A well built 12V 300W inverter consumes about 300A at full load give or take. Well, that said I think you would agree with me that it's not impossible nor dangerous to take 55 Amps out of a small vehicle 55Ah battery, right? Neither is it any more danger involved in taking off 300Amps from a 300Ah battery, (given you know what you're dealing with), it CAN KILL YOU, but not because the battery is programmed to explode like you try to scare people with. So you probably should stack up with a couple of heavy duty 230Ah batteries.
3000W inverters have been around for a long time running on 12V, but given the high amperage you're dealing with it's more than twice as dangerous as a 3000W 24V inverter. |
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albertok
New Member
3 Posts |
Posted - Jul 07 2009 : 11:11:34 AM
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| Furtermore it's worth to say about heavy cables and large inverters that for any 12V invertes from a few hundred watts and up, it is absolutely nessesary to keep cable lenghts to a minimum. Unless you have a wery deep wallet :) |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Jul 07 2009 : 3:09:10 PM
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A battery rated at 300Ah is tested with a 30A current, not 300A.
Cold Cranking Amps are tested for a very short duration. |
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albertok
New Member
3 Posts |
Posted - Jul 07 2009 : 4:14:22 PM
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I'm not talking about CCA, I'm talking bout if there is a chance for a battery to blow up when you draw from it Amps in the range of its rated Ah capacity. It will not. I have never had any of my approx. 55Ah car batteries that's been fitted to my car blow up even when I draw up to 200 Amps. 30 Amps run just by turning the key, another 75 - 150 when I crank it. Comes close to 200. When that's said I'm also aware of it's intended purpose, and the fact that you'd drain it extremely fast. But for testing purposes it's close to ideal because you get quick response from the battery when you test your low voltage cut-off, and voltage regulator. You just turn off your charger and voltages drop fairly quick.
Also something I forgot to mention earlier is the main reason many people buy 3000W inverters in the first place. Some just want to be able to run 1000W power-tools for a few seconds at a time now and then, some want the convenience of haveing a microwave owen in their trailer, boat or cabin. Most do not intend using its full rated power for an extended period of time. |
Edited by - albertok on Jul 07 2009 4:23:22 PM |
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antish
New Member
Ethiopia
1 Posts |
Posted - Aug 20 2009 : 2:48:23 PM
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| i have a problem in 12/24vdc input to 220/230vac output with 4000w and above.please help me to do that |
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superchad
New Member
3 Posts |
Posted - Oct 30 2009 : 4:32:06 PM
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| hi i saw this simple inverter when googling schematics for and inverter, i saw that it might have problems, well i need to know what would best for me, i need to make an inverter that is about 75 Watts to 100 Watts (for using a laptop in a car) i want it to be as simple and cheap as possible. thanks in advance. |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Oct 31 2009 : 12:16:01 PM
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This week, Canadian Tire store is selling a Name-brand 150W inverter for $19.99.
It would cost about $60.00 to make one.
They also have an 800W one on sale for $59.99. |
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superchad
New Member
3 Posts |
Posted - Oct 31 2009 : 5:19:14 PM
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| i estimated the originaly circuit aaron posted at around $20 to $30 to make (for the parts) i want to make one someday so id like to have the link to schematic for one. |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Oct 31 2009 : 8:36:31 PM
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The inverter here does not work.
You can make a simple square-wave inverter that does work (but poorly) for the same low cost. |
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00milind
New Member
India
1 Posts |
Posted - Nov 01 2009 : 01:31:41 AM
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| Looking for a pure sine wave inverter design, 48V to 240V, 50Hz, if anyone can help I would appreciate it. |
TEXA |
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Darkthero
Apprentice
USA
51 Posts |
Posted - Nov 04 2009 : 03:48:38 AM
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| i didnt take time to read all the above posts but i have posted a pic of the circuit . i have made changes, and it dose work this way. i got it sitting next to me running as i type this. notice the caps. and yes Tantalum caps do have a polarity. http://img522.imageshack.us/img522/952/inverter.gif |
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Darkthero
Apprentice
USA
51 Posts |
Posted - Nov 04 2009 : 03:50:30 AM
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| dont ask why im not entirely sure why. but i accidentally placed them like this and it functions |
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Darkthero
Apprentice
USA
51 Posts |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Nov 04 2009 : 3:33:23 PM
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quote:
Originally posted by Darkthero
dont ask why im not entirely sure why. but i accidentally placed them like this and it functions
You corrected the error of the backwards polarity of the capacitors.
But you did not correct the error where the transistors have avalanche breakdown when the capacitors try to drive the bases to -23V (the max allowed voltage is only 7V). The avalanche breakdown causes extremely high currents in the capacitors that causes them to explode even when their polarity is corrected.
You also did not correct the error where the base current for the transistors is much too small. |
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Darkthero
Apprentice
USA
51 Posts |
Posted - Nov 04 2009 : 4:04:52 PM
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quote:
Originally posted by Darkthero
i didn't notice those. but the way i have it now its putting out 130v and low amps and my caps havent exploded yet
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12/120V inverter again
