[Elecraft] K3 Voltage drop

Don Wilhelm w3fpr at embarqmail.com
Sun Feb 26 10:17:15 EST 2012


Joel,

Measure the voltage drop right at the power supply terminals - that will 
tell you how much of that total voltage drop is due to the power 
supply.  The rest is in the wire and connectors - there are 12 
connectors if your PowerPole distribution box has fuses, and 8 
connectors if no fuses.  The connectors can account for about 0.2 volts 
drop at 14.5 amps, and another 0.015 volts drop in the 8 feet of #10 
wire (you have to count the length of the return path too.  So 0.22 
volts of the total drop can be attributed to wire and the connectors.

A 1 volt drop at a 15 amp current draw is not unusual.

73,
Don W3FPR

On 2/26/2012 8:36 AM, Joel Black wrote:
> Ron,
>
> I didn't think to look at that last night, but I am testing it now into
> a dummy load at 50W.  I am using an MFJ-4125 with about 18" of #10 "zip
> cord."  This goes to a PowerPole DC distribution panel and there is
> another run of about 30" of #10 to the K3.  On receive, I have 13.4 -
> 13.5VDC (1.15 - 1.16A).  On transmit, it drops to 12.4 - 12.5VDC
> (~14.5A).  The wires are not even remotely warm.
>
> I do not have time to test with my Astron RS-35A at the moment, but I
> will when I get home this afternoon.  I also have an Astron RS-20A I can
> experiment with.
>
> Joel - W4JBB
>
>


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