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Thread: Is it Current Limiter Necessary???

  1. #1
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    Is it Current Limiter Necessary???

    Hi,

    I'm using:
    1) Intel Atom D945GCLF2 + 2GB Ram + 320GB 3.5" HDD + Custom Built Case.
    2) 80 Ah Battery + 8 Amps Charger

    Usage: Wanted to use as a FILE Server which is 24x7 online.

    I bought PSU from Ebay: http://cgi.ebay.in/ws/eBayISAPI.dll?...m=120433049001 & found its works fine without any problems.

    Currently I'm Running on 5 Amps Adapter to power-up my PC.

    Actually I Wanted to Power-up my PC with my BATTERY (80Ah) & Always it should be RUN on Battery itself.

    IS IT NECESSARY TO USE ANY CURRENT LIMITER BETWEEN PSU & BATTERY?? or SHALL I CONNECT BATTERY DIRECTLY TO MY PSU ???

    Also I got 8Amps Transformer based Charger to charge 80Ah battery.

    Can anyone advice me how to use 80Ah battery with 120W PSU Please..??

    Thanx.

  2. #2
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    I purchased the same power supply. By a current limiter do you mean Amperage? The PS is capable of putting out 120 watts, which at 12v would be about 10 Amps. I have the inbound power on mine going through a 10AMP fuse - from a car battery - don't know the amp hours of the battery.

    The problem that I have is the PS works fine at 12.8 vdc (from a regulated supply) but in the vehicle at 13.73 vdc (battery charging) the PS shuts down. Figured that the inbound voltage should be 12v to 15v but maybe not.

  3. #3
    Neither darque nor pervert DarquePervert's Avatar
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    If you mean a12v regulator, then yes, you should regulate 12v input.
    If you don't you risk frying that PSU (which is generally considered crap by most of us.)
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

  4. #4
    Fusion Brain Creator 2k1Toaster's Avatar
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    Quote Originally Posted by DarquePervert View Post
    If you mean a12v regulator, then yes, you should regulate 12v input.
    If you don't you risk frying that PSU (which is generally considered crap by most of us.)
    +1

    I had a picoPSU and a M3ATX, both sucked
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  5. #5
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    The power supply in question that I have - shows that with a 12.2 vdc input (error in initial post yesterday) the power supply will put out 12.18 vdc. At 13.6 vdc input the power supply shuts down. So the question is, how to regulate the inbound power. I am using this power supply to run a TVS (Taiwan Video Systems) 10" LCD monitor (12 vdc) and a satellite radio (5.2 vdc). On the bench it works fine - but the 13.6 vdc from the battery, with the altenator charging the battery, shuts the power supply down. Have looked at using a resistor across the power line to reduce the voltage, but then if the altenator is not operating, then the voltage could drop to 11.8 or less, which might affect the LCD monitor. Low Drop Out regulators are generally rated for a couple amps, and I would like to get the full 8 to 10 amps.
    Any suggestions on regulating the power?

    Thanks

  6. #6
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    Bugbyte's Avatar
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    I think that the OP is asking whether an 80 amp hour battery will fry his 5 amp adaptor if he hooks it up to the battery.

    The answer is NO, it will not. The battery will not suddenly push 80 amps through your 5 amp adaptor. It could be an 80,000 amp hour battery and not damage it. You are thinking of voltage.

    Amperage is how much power CAN be applied, if requested by the electrical device. Think of it as a 5 gallon bucket attached to a garden hose vs. a water tower attached to a garden hose. Obviously, the bucket runs out first but in both cases the garden hose is not damaged.

    What you want to watch out for is voltage mismatches. That's kind of like the same garden hose example hooked up to a low pressure connection like your house vs. a high pressure one like a fire hydrant. THAT will destroy the garden hose.

    @micky53usa - if your power supply shuts down at 13.6 volts, you need a regulator. Cars will often output as much as 14.5 volts from the alternator. Using a resistor will cause a lot of heat, especially if you are going to pull 8-10 amps.

    Carnetix used to make a regulator (2190?) that worked great. All of the major car PSU's have regulation built into them and negate the need for the power supply. If you only need 8-10 amps, then you're looking at a PSU that needs to supply perhaps 120 watts. You can use some of the online power calculators to see exactly what your setup will draw on each rail, but unless you have something really weird, a PSU in the 160 watt range should do fine.
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  7. #7
    Constant Bitrate
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    It looks like you got one of the PicoPSUs from Mini-Box. The ones rated for car use have a -WI designation on them for Wide Input voltage range. The other ones (and probably the one you have) require regulated 12v input.

    What's worse is that the image of your supply in the e-bay posting doesn't match any of the ones posted on mini-box's website. Either you have an earlier revision or a cheap knock-off of a PSU that was never thought to be that good to begin with.

    For the cost of getting a 12v regulator at the required current rating to feed that poser supply (typo left in, I like it), you might be better off just getting a new one that can handle automotive voltage ranges.

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