Computer Power Supply Converted to 13.8V for Radio

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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 10 Jul 2012, 21:28

yeah i have the motherboard connector, the +5v and the 3.3v with there sence are the only other ones paired up.... someone else said check the meter... would a plug socket be any good mine can measure that voltage
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 10 Jul 2012, 21:46

Lol im sure my meter is knackered, pluged it in the wall and it reading 350volt ac and riseing lol lol
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by sureshot » 11 Jul 2012, 00:28

If our mains voltage is 350 volts single phase the UK power grids got troubles, if you read it on the appropriate AC Volts range then yes the meter has problems, ive got a few meters and that's one of them same as yours mines been ok for about 3 years so far, but yours might have developed a fault, as your ATX reading is DC volts i was thinking more along the lines of another power supply a known good one or maybe a 9 volt pp3 or some thing similar car battery etc, it just really odd to get them readings, see if you can get hold of another meter try that, but do test yours on a known DC voltage. :)
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 11 Jul 2012, 14:45

lol ok think the meter knckered.... i think i must be the only person with a car that can do 20+v from a 12V batt lol.......... at most the batt should be about 14v
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by sureshot » 11 Jul 2012, 17:29

Yep nominal car battery voltage 14.4 volts, so when you get another meter measure again it should read ok.
I would not run a radio on it until you measure the voltage and i normally use a low voltage halogen bulb 12 volt type to test the supply for a couple of hours for stability of current measured meter in series with the load bulb and voltage after the units been run heavy for a few hours, you can normally pick up the 20 and 50 watt halogen bulbs in the pound shops, i would put a 50 watt or even two in parallel for a couple of hours on the 12 volts ATX lines.

Let us know how you get on. ;)
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 11 Jul 2012, 19:14

as in a car halogen bulbs? they have 3 prongs dont they? how would i wire them up?
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 11 Jul 2012, 19:21

hdjmings1 wrote:as in a car halogen bulbs? they have 3 prongs dont they? how would i wire them up?
and new meter worked.... but both the 4.7ohm and the 10ohm give me the same reading at 12.14v :D :D
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by sureshot » 11 Jul 2012, 19:58

OK use the 4.7 ohm on the +5 volts leads, but if you put the load resistor on the +12 volt rail it must be 10 ohms 20 or 25 watts, but go with the +5 volt rail and the 4.7 ohm 10 watt resistor, good its giving the right voltage.

the three pins is probably high and low beam, i dont do much automotive stuff, the halogen bulbs i was referring to where the dioctric down spot lights the indoor low 12 volt ones the quid shops often have 20 and 50 watt lamps in stock, but your car lamp will do but i dont know how many watts it is, divide the watts of the lamp with the voltage 12 volts to get the current, so if 20 watts 20/12 = 1.66 amps load, you can put the meter in series with the lamp to confirm the current if you wanted, a bigger load 50 or 100 watts say two 50 watt lamps in parallel, one would still be fine though, the rest after is putting it together with how you want it, but keep the load resistor clear of any other components for safety, tied to the vented slots or in the air flow keeps it cool, but anywhere is fine. :)
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 13 Jul 2012, 15:29

hi just quick question for anyone to answer please, the pic below are 2x 50watt halogen bulbs i wired up to test the power supply e.c.t

but when i check the amps it says it only drawing just over 1amp (1.08 amp)
is this correct? as i thought it might pull at least 8 amps?
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by sureshot » 13 Jul 2012, 17:02

This should help, even for the basics for testing. ;)
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 13 Jul 2012, 17:17

lol should help lol but lol............. so would mean as i have 2x50watt lights running on 12v so then 100/12=8.3 amps? but its not it reads just over 1amp

to read this i put the neg lead of meter on the end light on the live lead on that light and the live end of the meter on the live terminal of the psu? was this right
as when i put the meter leads on the psu it shuts the psu down
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by sureshot » 13 Jul 2012, 17:35

Your shorting out the psu, check your meter lead sockets are plugged in for measuring DC current, in the image below imagine the battery is the psu so power source, use two lamps in parallel, red positive probe goes in series to the highest potential the psu + volts, the negative lead goes to the lamp wire so your opening the circuit and putting the meter in series with two lamps in parallel. :)
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 13 Jul 2012, 18:27

lol got it, yeah just over 8 amps lol, where would i measur for voltage drop? at the end of the line or at the psu terminals?
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by sureshot » 13 Jul 2012, 19:02

At the terminals is fine, the chart below is a guide to tolerances, but bare in mind the pc uses all rails, as where just using the +12 volts rail, not its intended purpose but works fine volts drop with load will vary from one ATX to another as the circuits are built different to sense load. :)
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Re: Computer Power Supply Converted to 13.8V for Radio

Post by hdjmings1 » 13 Jul 2012, 21:19

well pulling 14.7 amps the voltage at the terminals stay at 12.08v, when no load is on the supply the standered volts are 12.09/12.1v

but the real test will be tomorrow :lol:
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