[Elecraft] New Output Power Issue

[Don Wilhelm]

Despite the potential for voltage drop, I would not forget the fuse at 
the power supply end of the wire unless you are certain the power source 
has adequate overcurrent protection built in.  The blade type fuses with 
tight fitting sockets will cause very little voltage drop.  If the 
connection is not in the milliohm range, connection tightness is to blame.

That fuse is not intended to protect the equipment connected, but is 
instead to protect the wire from a short circuit.
Many power supplies do have adequate overcurrent protection - however ---

I hear of instances where this was not in place when the power source is 
a battery.  In the event of a short at the end of the power cable (or 
internal to the cable), a LOT of energy can be available which will have 
current sufficient to melt copper conductors of any size and spew molten 
metal all over the place - a personnel and a fire hazard.

Low voltage high current power sources can be just as maiming as high 
voltage supplies.  Please be safe!

Merry Christmas and Happy New Year.  Keep all hams healthy and free of 
injury in the coming New Year.

73,
Don W3FPR

On 12/24/2012 7:21 PM, Bill K9YEQ wrote:
> Ian,
> As a bottom up reader, I see you have plenty of advice already.  I would
> also like to point out in addition to what I posted below, I had an extra
> set of fuses and a Red-Dee connect 45 amp distributor in line with the
> battery backup/power supply and this alone added > 1.5v drop.  With those
> two items out of line, I now see the ~ 12v to my radio and I get out the
> full 100 watts from the radio under load.  Those two items added an
> additional  4 connections or 16 surfaces.  If I wanted almost zero drop, I
> would take out the RigRunner and put power directly to the radio.  This
> would drop it further.
>
> 73,
> Bill
>