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How to redesign PCs PSU so it work on cars 12V?

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DimaA

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Hacking cmputer's PSU

I am planning to put a PC in my car to view DVD and listen music,and my concern is the Power supply.I don't want to use inverters to get 220V,too gangerous and expensive,so I thought about redesigning the PSU,so it should work from car's 12V. The idea is to use PWM controler like SG3595 and use modified transformer to get the needed voltages.
Anyone have done something similar or has an ideas how to do it?
 

Re: Hacking cmputer's PSU

Hi,
A pc is not optimised to consume a low ammount of power, it's big, it is not resistant to vibrations, extended temperature range, humidity..... Why don't you use a laptop? It is easier to build a boost converter to obtain 18-20V, ammount required by laptop from car's batt.
 

Re: Hacking cmputer's PSU

is there really a problem to use pc? I think laptop will not be suitable,because I want to connect external sound card for better music performance and also a gps card for navigation.Also I will need a wi-fi lan card to connect my main computer (to download songs) so I don't know how can I integrate all this in laptop
about pc104 board - they are extremely expensive,about 500$ for a board for a PIII,better computer will cost much more for sure.
 

Re: Hacking cmputer's PSU

Hi,
Obviously, it is not a problem to use a pc. There are only some disadvantages to use a pc instead of a laptop, but if you want to ignore them , then it's ok. After all, they are your tools :). First would be the size, a laptop is smaller. Second, most of the extension boards inside a pc are connected using slots (pci or isa) which are not designed to work in automotive environment. The same problem stands for coolers in the pc, both cpu and power supply. Also, the harddrive is not designed to work in automotive environment. The effect is that in time, you system will most proably crash because of its components. Also the temperature is a problem, especialy when it has rapid variations. This in combination with high humidity will form condens inside the pc. This is a good cause to kill your system. Maybe the most important thing is the cd/dvd unit, which is also not designed for such an environment. Vibrations ca seriously affect the functionality of a descktop pc cd/dvd drive, because the primary reading system is purely mechanical. For example, a portable audio cd player is designed with a very high ammount of buffer memory, to compensate reading errors due to vibrations (both, for cars and pedestrians). An audio cd player for home use does not have the buffer memory. Slap it during play, and it will interrupt the audio signal. About the extensions, you can connect an external sound card, I think if you do some search on the web you will find audio cards with pcmcia connection or usb. Also, the gps receiver outputs the data in serial format, rs232 or usb. A laptop have both. And one other issue: a gps system is designed for navigation, so the most gps tools will have serial, usb or maybe pcmcia connection. I really do not think there are GPS isa or pci cards available. Who needs gps for a desktop pc ?!? What for ? WIFI connection is available also for pcmcia or usb. Dima, this is just an opinion, they are you tools, do what you want. Good luck. :)
 

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Enjoy! :)
 

Re: Hacking cmputer's PSU

All the comments above are valid. I have had a PC in my car in a VERY well designed case with all the possible precautions for vibration and temperature changes, as well did I use the best components available.

The PSU was a normal ATX brick modified for 12V, that can be done rather easily.

However, when driving over a speed bump, the system would regularly hang, probably due to loose connections on the bus. The DVD player was no good when driving, when parked it worked perfectly. The motherboard broke down 5 times, for no clear reason. When starting a cold car, condensation would form during warm up, causing all kinds of erratic behaviour. Also the sleep mode of the PC was an issue, it kept on draining 7 or 8 watts even though the power supply was over 90% efficient, causing flat batteries and making me install a second enterainment battery system with its own alternator. I used a deep cycle battery because the normal automotive battery lasted less than 3 months before it would loose capacity.

I used a 2.5" laptop HD, which performed fine under all circumstances, though.

Then there were the voltage spikes. Even though the power supply worked well, the spikes caused when starting the engine etc. at best appeared like random keystrokes, but more commonly caused crashes.

Running SiSandra when driving, detected all kinds of hardware errors, which disappeared when parked.

Bottom line: don't use a PC in an automotive environment. Get an industrial board or a laptop. You'll save yourself money and time.

Bert
 

Re: Hacking cmputer's PSU

8) The main problem is hard disk and Cd rom drive because they are electromechanical components, a hard disk will be damaged if it is used in mobile application due to vibration. you can try to mount the hard disk on a spongy material to avoid shock to it.
 

Re: Hacking cmputer's PSU

you might need dc converter to change from 12 V car battery to 3,3,V, 5 V,-5 V, -3,3 , 12 V. Isuggested that you buy such converter then build your self because it'more cheap
thanks
 

Re: Hacking cmputer's PSU

just un plug power supply of pc and userequired power from car .
12v . 5v 3.3 v etc..
 

Hacking cmputer's PSU

How about using memory cards or usb memory sticks for storage. Isn't there an option in BIOS to boot computer from such devices? Shouldn't be many problems due to vibration because it's a solid state device.

Sputnik :idea:
 

Re: Hacking cmputer's PSU

Why not just build a new front end for the PC PSU like this:
 

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