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Thread: Regulating Car's Voltage to 12 Volts

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    Regulating Car's Voltage to 12 Volts

    Ok, I've tried twice to come with a circuit that will regulate a cars voltage to 12 volts. Reason being, I bought one of the cheaper 200 watt unregulated power supplies and an ITPS and am now in a bad position. As far as I can tell nobody offers circuits for this task that cost less than $70 so I am asking for help. If you have any idea on how to build a regulator circuit that can handle between 10 and 20 amps I'd appreciate your input. I have looked into both Linear and Switching Regulators and from what I see both of them would require that I first boost the voltage to around 20-25V DC and then scale it down. I am not looking for a unit that can survive cranking, however after I turn my car off, it has to be able to output 12 volts so that the computer won't crash instead of gracefully shutting down. The simpler and cheaper the circuit the better, but at this point I'll take just about anything I can get. Thanks.

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    It's probably not what you want to hear, but I suggest doing a cost/benefit analysis and determining whether or not it you might save by just buying an Opus. Remember, it's not just money, it's also time. If skipping the Opus means that 6 months from now you still won't have a reliable working system, the extra money up front might be worth it.
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    Quote Originally Posted by Chairboy
    It's probably not what you want to hear, but I suggest doing a cost/benefit analysis and determining whether or not it you might save by just buying an Opus. Remember, it's not just money, it's also time. If skipping the Opus means that 6 months from now you still won't have a reliable working system, the extra money up front might be worth it.
    Yeah I know, if I hadn't already spent $90 I'd be all over the Opus, however unfortunately I have and I just can't imagine spending around $280 just to get the power working for my carputer. One idea that I have, that would take some work to get it properly working is to use an inverter and a regular atx power supply which would provide power to my ITPS and DC-DC powersupply. I realize this would run into a lot of problems as a result so it's my LAST option.

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    I must be missing something. The ITPS is a regulator. If you put it in line before the 200 watt power supply, it should regulate the power to 12 volts.

    Not sure if it can handle 200 watts, but it handles my 120 watt supply okay - after I put a fan on the heat sink to keep it cool.
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    Nic
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    the older itps' can only handle 60w of power, the newer ones i believe can handle a little more? either way its a waste using a 120w PSU with an itps, you arent reaching your power supplys full potential, but hey if it works, dont change it!
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    ohh and putting a fan on the heatsink probably means it can also handle more too
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    Triwav,

    One thing you may want to consider is taking another look at the CarNetix P1260 regulator. You could keep your "200 Watt" PSU and put the P1260 in place of the ITPS. It has similar functionality, but actually works! It will provide up to 60 watts of power to your PSU, but that's really all the regulated power your "200 Watt" psu can provide (see this artice on our website . The "200W" is vendor B).
    And, you'll get the added benefit if surviving crank, remote enable for your audio amps, and pulse-start from a remtoe wireless device.

    MP3Cars.com store will have these P1260s in stock soon...

    Let me know if you have any other questions. Or visit our support forum .

    Enjoy!
    MikeH

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    Quote Originally Posted by MikeH
    Triwav,

    One thing you may want to consider is taking another look at the CarNetix P1260 regulator. You could keep your "200 Watt" PSU and put the P1260 in place of the ITPS. It has similar functionality, but actually works! It will provide up to 60 watts of power to your PSU, but that's really all the regulated power your "200 Watt" psu can provide (see this artice on our website . The "200W" is vendor B).
    And, you'll get the added benefit if surviving crank, remote enable for your audio amps, and pulse-start from a remtoe wireless device.

    MP3Cars.com store will have these P1260s in stock soon...

    Let me know if you have any other questions. Or visit our support forum .

    Enjoy!
    I'm afraid 60 watts will not be enough, I guess I should of explained my setup. I'm using a duron 700 with a microatx board um. 256 Ram 3.5" 5400 RPM system hard drive and will have either a 60GB or 80GB external 2.5" drive for all my mp3's. I will eventually be using an all in wonder card in order to receive fm radio. I'm also going to have a full size dvd drive along with several USB devices. When I did my calculations, I came out to around 123 watts which is obviously just an estimate but well over 60 watts. What I am really looking for here is somebody who has succesfully designed a circuit specifically for regulating the cars voltage to 12 volts AND can provide between 10 and 20 amps. Oh yeah, one more thing. I'm pretty sure they shouldn't draw a lot of power but I am also going be using the power supplies 5V channel to run REM for my two amps JBL BP1200.1 for my subs and a cheaper four channel JBL amp for my component speakers. I will also have to run one to the powered antenna so it will go up and down when I turn the computer on and off. Thanks for all your help people.

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    triwav,

    You're right. With that type of power requirement you'll certainly be over the 60 watt limit. In fact your "200W" psu will also choke since it's regulated output is only 60 watts. Here's the spec of its rails. Sorry the 2 figures don't line up...
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    MikeH

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    Quote Originally Posted by MikeH
    triwav,

    You're right. With that type of power requirement you'll certainly be over the 60 watt limit. In fact your "200W" psu will also choke since it's regulated output is only 60 watts. Here's the spec of its rails. Sorry the 2 figures don't line up...
    That is true, that is why I need a regulator so that I can make use of the other 140 or so watts of power coming out of the 12 volt rail. I know that it will work properly because I have used the system without the ITPS in my house with a AC-DC ATX powersupply running my DC-DC 200 watt power supply off the 12 volt rail of the ATX power supply. So it does provide 200 watts, it's just not 200 watts regulated.

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