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DC Power Loss Using 16-AWG Stranded Speaker Wire

09/17/2009 11:46 PM

I have a 7.2V 3300mA battery powering various devices. The circuit consists of a 36" length of 16AWG double stranded copper wire. It is labeled Radio Shack speaker wire, looks like zip cord to me. What is the formula for calculating the effect that varying lengths of this zip cord would have on effective power transmission and/or battery life? Instead of 36" what if the circuit was as short as 12" or as long as 72"? Thanks - Ed

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#1

Re: DC power loss using 16AWG stranded speaker wire

09/18/2009 2:56 AM

It's probably almost certainly not worth worrying about.
But if you really want to find out, then measure it, don't calculate it.
Measure the current you are drawing at full load (a cheap multimeter will do the job).Then measure the voltage from one end of the cable to the other (on,say the positive wire), it will probably be just a few millivolts.
Multiply the 2 figures double the figre because you will have the same loss in the return (negative) wire, and there you have it, the power lost in the cable.

Del

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#4
In reply to #1

Re: DC power loss using 16AWG stranded speaker wire

09/19/2009 2:18 AM

The 1980 Radio Amateur's Handbook states the resistance of 16 gauge copper wire to be 4.094 Ohms per 1000 feet at 25 degrees Celsius, so the theoretical voltage drop in three feet of this two-conductor speaker wire will be 24.5 millivolts at a current of one Ampere, about .3 per cent of your nominal battery voltage. If this is an intolerable voltage drop, you need to install a regulator.

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#5
In reply to #4

Re: DC power loss using 16AWG stranded speaker wire

09/19/2009 5:55 AM

Regards.

Regulators work where the power-source has a redundent power [Voltage wise & Current wise]

Here the Battery has a fixed Voltage; which can drop on increasing load & no buck-up is possible.

Had it been an AC power Rectified; having higher than the required DC volts; it was possible.

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#8
In reply to #5

Re: DC power loss using 16AWG stranded speaker wire

09/19/2009 12:06 PM

as I stated BATTERIES will function as a capacitor and a variable coil will work to adjust the voltage drop this is rudimentary electronics............any voltage may be manipulated through the use of a holding charge the volumne of the charge may be tuned to the required voltage through coils or as you need them named transformers.....transformers can be hand wound separating plates can be hand crafted even motors buy a book from radio shack learn to read english?

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#13
In reply to #8

Re: DC power loss using 16AWG stranded speaker wire

09/22/2009 6:10 PM

Dear Queue !!! A smple coil can't do any thing except store some energy which can only be disharged & brought into use [A circuit is needed]. secondly a triac works only on AC Supply to control power NOT on DC. A SMPS circuit is needed to increase or decrease a DC Voltage like Battery. Such units are available Off-The-Shelf for almost most popular purposes in various voltage to Voltage in a wide range of power rating. Have a nice day !

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#7
In reply to #4

Re: DC power loss using 16AWG stranded speaker wire

09/19/2009 11:58 AM

nice but you are redundant tell the man how to build a regulator from discreet parts instead.

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#10
In reply to #4

Re: DC power loss using 16AWG stranded speaker wire

09/22/2009 9:22 AM

Good answer.The rest are speculative and do not address the OP's question directly.

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#11
In reply to #10

Re: DC power loss using 16AWG stranded speaker wire

09/22/2009 9:35 AM

speculative and do not address the OP's question directly.????
Cobblers....#1 does what it says on the tin.
Anyhow...
your comment contibutes...
hang on let me just add up all the valid points you make...
Errr...
Ah yes...
I make it...
Absolutely nothing.
Del (baaaad grumpy kitty)

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#2

Re: DC power loss using 16AWG stranded speaker wire

09/18/2009 3:14 AM

I'll tell you some of the little known secrets for extending battery life, just promise not to tell the others...

Make sure that when the equipment is 'OFF' or in it's inactive state it is drawing as little current as possible (ideally zero). This sounds obvious, but you'd be surprise how something which runs once a day at a fixed time can eat up the current just running it's internal clock.

Make sure all the exraneous bits of circuitry, like indicator lights are removed.
Make sure it switches itself off and doesn't rely on the operator to remember.
Del

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#3

Re: DC power loss using 16AWG stranded speaker wire

09/18/2009 4:06 PM

IDEA: longer wire creates more static noise and can be reduced by increasing it's internal diameter IE... bigger diameter wire less static noise delivers more voltage faster which is measured as current or amperage...... now the application of POWER is your option if every device inline with the supply is of the same valued resistance no problem but if they are not the you will cook the lesser values and discharge the supply through them quickly....solution Variable capacitors in a TANK circuit IE... a cap and coil would allow you to trap unwanted RF interference "NOISE" for the specific device and control the supplied current to the device at the same time.

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#6

Re: DC Power Loss Using 16-AWG Stranded Speaker Wire

09/19/2009 9:08 AM

(look up resistance of 16 awg wire x 2) x load.

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#12
In reply to #6

Re: DC Power Loss Using 16-AWG Stranded Speaker Wire

09/22/2009 11:26 AM

I should have resourced available information, but I would not have learned as much as from contributors here. Thanks to all of you. - Ed

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#9

Re: DC Power Loss Using 16-AWG Stranded Speaker Wire

09/19/2009 12:17 PM

EJAY: what are you building? is this an audio system> if so simply install a cap and coil at the speakers terminate points use a variable resistor or a potentiaometer same thing they come in micro to mega sizes and you can build you own just depends on how much time an money you have to fool with. measure the impedance and maych it at each speaker and you will have balanced your potentials.if you use dial indicators within each speaker cabinet you can effect a surround echo chamber.

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#14

Re: DC Power Loss Using 16-AWG Stranded Speaker Wire

10/26/2009 11:46 PM

Measure voltage at batteries then at load then subtract and R=E/I then use house wiring may work better.

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#15

Re: DC Power Loss Using 16-AWG Stranded Speaker Wire

12/09/2009 2:12 AM

Hallo,

It is very easy. Try this formulas. R=Rho*l/A. l in meter, A in mm^2 and rho about 0,0175. U(R)=R(cable)*I. That's all

Be carefull. You have to count the length twice.

It should be nearly the same, what you are measuring.

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