Eddy_P Posted July 24, 2005 Report Share Posted July 24, 2005 For this hypothetical, let's assume that I do not want a lap-top computer. Let's say I want to take my home computer with me in the back of my utility, but it has to fit within an area of 500 mm wide x 300 mm high. A wooden box of length X would suit this storage and transport problem. It needs to hold the computer parts set out sideways ready for use, plus a power source. How long would the box have to be ? In the side of the box, a window will be made for the screen to be seen, with a sliding door that reveals and gives access to three compartments for the mouse, keyboard and CPU unit - so it can all be used on site from the side of the utility vehicle. The monitor (400mm wide and just under 300mm high), keyboard and mouse pad (480mm + 220mm) and desk-top CPU unit (450 x 450 mm) would take up the first 1600mm (400mm for the screen window and 1200mm for the others). This leaves a minimum area of 500 x 300 x 1200 mm for the batteries (being the region behind the sliding door that opens). Questions:1) What type of battery would power this home computer so that I could use it from the rear of my utility ? 2) How much of the 500 x 300 x 1200 mm area would they take up ? My thoughts:I assume that something like a series of car batteries would do the job (but I am probably wrong).To obtain the 240 volts required to power a 240 volt computer system, I calculate that I would need 20 twelve volt car batteries. (12 V x 20 = 240 V) My car's battery is 220 x 250 x 200 mm. 20 of these batteries (as 2 x 10) would take up 2000mm. This is more than I have available to me, as the maximum length of the box can only be 3000mm. So, what type of battery (which determines its dimensions) - and how many of them - would be needed to fit in an area no larger than 1400mm long, 500mm wide, and 300 high ? Thanks,Eddy Quote Link to comment Share on other sites More sharing options...
C1ay Posted July 24, 2005 Report Share Posted July 24, 2005 You can buy an inverter that connects to your car batteries that will convert the voltage to 240 volt. Just buy one that's around 500W or so. Quote Link to comment Share on other sites More sharing options...
Boerseun Posted July 24, 2005 Report Share Posted July 24, 2005 Hi, and welcome to hypography! Using a series of car batteries is a bit clunky, seeing as your computer and its peripherals run much lower, in the 4 to 12 volt category. But, your pc's power supply was built to handle power fluctuations, and shouldn't be dispensed with if you can't replace it with something suitable as a power regulator. I'd recommend investing in a power inverter, that'll take your van's 12V DC and convert it to 240V AC. Then all you'd have to do is plug it into your lighter socket, or wire it up to the circuit feeding the lighter socket, and Bob's your uncle. A mid-range inverter is about a third the size of an average 12V car battery, and will set you back in the region of a single battery's price. I'd also recommend using a flat panel which you can take out of its housing, instead of a CRT. That'll reduce the strain on the inverter by a bucketload, and also save you lots of space. So, you'd still have your pc's power supply acting as a regulator, and the cool thing is you can even run a kettle to make some coffee on site from the inverter as well! Let me know how your project is going! Quote Link to comment Share on other sites More sharing options...
Jay-qu Posted July 25, 2005 Report Share Posted July 25, 2005 apart from problems of having 20 car batteries you are also wrong. The 240V your computer recieves from your house is AC and hence the 240V is a RMS voltage... your best going with what boerseun said, but i have never heard of someone wanting to do this befors so.. yeah let us know how you go Quote Link to comment Share on other sites More sharing options...
alexander Posted July 25, 2005 Report Share Posted July 25, 2005 You are much better off with a series of bike batteries then one car one, they will hold more charge for longer per same area, plus you are talking 600 watts out of those, thats a lot of current to be running. Inverter is a splendid but wasteful idea, it is very much not efficient, and you'd be wasting all that precious electricity, however i can't also imagine anyone building a transformer for a motherboard at their home convenience without a degree in electronics. So I would suggest scrapping the idea with using a conventional mobo and do something crazy, like we always do. choice #1, you could build it using an X-Box, however the power converter is still inside i beleive so it is not such a great idea, but saves space. Choice #2 building it out of a linksys router, and yes there is a project that is doing just that, now that should solve some problems, i beleive that that box has an external power supply, which means bingo for you, it will be pretty easy to buid a transoformer that converts DC into variable DC, square wave, and really high frequency, then pass that through a transformer to get the right voltage, and add a diode bridge, some resistors, and a few capacitors just in case, check to make sure you got the specs on the power supply right, the specs outlined on the linksys's power supply, and you are good, all you have to do is hook up positive and negative to the original power supply wire and plug it into your linksys router/Linux box, little space, and you have a Debian box to carry around with you :hihi: Quote Link to comment Share on other sites More sharing options...
C1ay Posted July 25, 2005 Report Share Posted July 25, 2005 it will be pretty easy to buid a transoformer that converts DC into variable DC, square wave, and really high frequency, then pass that through a transformer to get the right voltageTransformers only work on AC.... Quote Link to comment Share on other sites More sharing options...
alexander Posted July 25, 2005 Report Share Posted July 25, 2005 sorry i had another sentense typed there before and that word just happened to be there, i meant power supply, not transformer Clay.... Quote Link to comment Share on other sites More sharing options...
alexander Posted July 25, 2005 Report Share Posted July 25, 2005 oh and transformers do work on variable DC, since you get a wave, and thus the oscillation of charge from positive to negative, a magnetic field will be generated by the tranformer coil and you will induce a current in the second coil, so you are all set :hihi: Works in your monitor doesnt it? Quote Link to comment Share on other sites More sharing options...
Erasmus00 Posted July 25, 2005 Report Share Posted July 25, 2005 oh and transformers do work on variable DC, since you get a wave, and thus the oscillation of charge from positive to negative, a magnetic field will be generated by the tranformer coil and you will induce a current in the second coil, so you are all set :hihi: I'm assuming you mean square waves with variable DC? When you have square waves input to a transformer, the output instead of having a nice square waves is a series of delta function pulses timed to the square wave rise time. These delta functions aren't fit for much in the way of running something. -Will Quote Link to comment Share on other sites More sharing options...
Qfwfq Posted July 25, 2005 Report Share Posted July 25, 2005 Inverters use a fast duty cycle and smoothing to approximate a sine wave. Alex, couldn't you have posted an attachment with a nice thumbnail? The thread would be easier to read! :hihi: Quote Link to comment Share on other sites More sharing options...
C1ay Posted July 25, 2005 Report Share Posted July 25, 2005 oh and transformers do work on variable DC...Well yes, they do work on pulsating DC but I was taught that this was a poor design practice because of a poor efficiency in operation. Quote Link to comment Share on other sites More sharing options...
alexander Posted July 25, 2005 Report Share Posted July 25, 2005 Alex, couldn't you have posted an attachment with a nice thumbnail? The thread would be easier to read!is that better? Quote Link to comment Share on other sites More sharing options...
Boerseun Posted July 25, 2005 Report Share Posted July 25, 2005 Dude - the fact that you've even contemplated throwing 20 car batteries in the back of your van, tells me that the safest route for you would be to go the inverter route. No hassles, no funky circuit designs, no stress about sine waves. Forget the wastefulness. Plug and Play. And as a bonus you get a cup of coffee on site as well. Quote Link to comment Share on other sites More sharing options...
alexander Posted July 27, 2005 Report Share Posted July 27, 2005 Wasnt the original design requiring you to be able to care the computer, if not, heck, 8 bike batteries and some 0 or 4 gauge wire to the car battery into a simple inverter should work out just fine, and your milage wont get killed from all the extra weight, and the computer will be able to safely run for 9-10 hours without having to start the engine to recharge the batteries... actually if you can get your hands across some silver batteries used on the space shuttles, those are about 1/2 the size and hold waay more charge for much longer. I've talked to a guy who had one in his car instead of the original battery, didnt need switching for 20 years, he switched 3 cars and never had to change that battery... Quote Link to comment Share on other sites More sharing options...
alexander Posted July 27, 2005 Report Share Posted July 27, 2005 Well yes, they do work on pulsating DC but I was taught that this was a poor design practice because of a poor efficiency in operation.that is true, but it very much depends on the transformer you use, I saw some website that can't recall for the life of me, that had somparison in efficiency of different makes of tranformers while using square wave, but I'll ask around, i know someone who is a radio engineer but worked for years designing power supplies for the new equipment that the institute developed, see what he says... Quote Link to comment Share on other sites More sharing options...
C1ay Posted July 27, 2005 Report Share Posted July 27, 2005 Wasnt the original design requiring you to be able to care the computer, if not, heck, 8 bike batteries and some 0 or 4 gauge wire to the car battery into a simple inverter should work out just fine, and your milage wont get killed from all the extra weight, and the computer will be able to safely run for 9-10 hours without having to start the engine to recharge the batteries....At my last job I made a little wireless cart that the warehouse used to enter inventory. It was a no frills desktop box and flatscreen monitor with a bar code printer. The whole thing ran on a single 400 CCA 12V car battery connected to a 500W inverter. It was used 8 to 10 hours a day and connected to a trickle charger at night. We never had trouble making it through the day. A deep cycle marine battery would last much longer than this even. OTOH, if I rebuilt it today I'd use a notebook. You could run it for days on a single charge. Quote Link to comment Share on other sites More sharing options...
Dark Mind Posted July 27, 2005 Report Share Posted July 27, 2005 Awaiting C1ay's reply... Been working on it since 7:15 Quote Link to comment Share on other sites More sharing options...
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