Voltage wiring power query

  philonp 08:00 04 Apr 2007

I am thinking of connecting a switch to my internal fans, but I noticed that when I daisy chain my 2 rear fans to the psu with my cathode light all 3 seem to lose some power. But if I separately connect them to the psu they are okay. So I was wondering if
the voltage power would be affected by the length
of the wiring? And will my plan of connecting a switch which will further increase the length of wiring affect the supply of power? Does daisy chaining affect the supply?
My psu has 2 power lines with 2 plugs each for a total of 4. I connected 1 plug for harddrive and
the other one free. And the other line is one for dvd writer and the other for the fans and cathode light.

Just to be sure my pc is a celeron d, 1gig ram, 1 harddrive, geforce 6600, dvd writer, soundcard,
2 80mm rear fans and 1 cathode light.
psu is 400w.

  wee eddie 08:33 04 Apr 2007

At what voltage would the Power Company have to generate to get it to you at 240 Volts?

It may be that you need PSU that is able to deliver more Power.

  fonkets 08:45 04 Apr 2007

You will need to set the fans in parallel and not series (daisy chain).

  Diemmess 09:07 04 Apr 2007

I'm puzzled as to what you have and what you want to do?

fonkets is correct, parallel not series connection.

Most likely, the case fans need 12volts d.c. and the cathode light?
Is this all in a new case and the light is part of the decoration?

There is a maxim about "if you don't put it in it can't go wrong and costs nothing!"

Beware of damaging something you are not sure of.

The voltage drop along the length of a wire is a function of its electrical resistance and the current flowing. For your purposes you would not notice any difference between a short link and one 100' long.

  filthyphil 09:26 04 Apr 2007

fonkets and Diemmess are right you need to wire them in parrallel. the voltage will drop accross any component requiring electricty before it carries on therefore as for instance the first thing uses 1.2v of the 12v you only have 10.8 for the rest and obviously if the next uses 2.6v you only have 8.2 v and so on whereas in parrallel the voltage stays the same and only the current will drop which is not a problem if your PSU is man enough to handle the power requirement

  philonp 18:47 04 Apr 2007

Firstly, a very big thank you for your help.
This is what I am getting from you guys:
I should not daisy chain my fans and cathode light together. I should separate them. But then if I connect a fan to my dvd writer, will it not affect the power to the dvd writer? The same also if connected to the harddrive?
This is how the plugs are: (which is suppose to be wrong based on your advices.)
*I try giving my harddrive priority.
So I should do something like:
psuline1-plug1a-fan1plugin-fan1plugout-dvd writer
Is this correct? (but then power to dvd writer would not be correct based on what you guys stated.)

Finally, about wiring a switch which will extend the length of the wire, will the LENGTH affect the voltage? (Diemmess: not notice any difference between a short link and one 100' long.)
So is that a no?

  philonp 18:58 04 Apr 2007

To Diemmess, my case has a side window. So I bought
a cathode tube light just for fun. It's the kind that we can buy in pc shops for modding.
As to the fans, I live in the SEAsia and it gets hot
here up to 30+ Celsius. The pc gets really hot so I have them.
To Filthyphil, my psu is 400w. It should be enough,
shouldn't it?
Thanks again.

  Diemmess 19:40 04 Apr 2007

Glad you explained about the light and the ambiant temperature.

Agree your PSU should be enough. The fan/DVD power line is OK too.

The standard power cables should all look the same and really are interchangable.

Provided the TOTAL load doen't exceed the PSU's ability to supply, it shouldn't make any difference wigh supply feeds which gizmo.

On the whole, fans are a very low drain on power and can almost be discounted.

  woodchip 20:14 04 Apr 2007

We are only talking 12volts for fans, not 240volts. Having too thin or too long wires increases resistance so amps are slowed down. But it would be rubbish wire if you see the power drop. Daisy chaining is not a good idea

  woodchip 20:15 04 Apr 2007

Is that how you do your Christmas Tree, No wonder there are Fires

  philonp 22:15 04 Apr 2007

Thanks again for all your replies.
To Woodchip, so do you mean that it would be okay as long as it's not too long and it's good quality wire?
I am only planning on attaching about a foot long wiring to the switch. Hope that is not considered long.

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