[Elecraft] Anderson Powerpole voltage loss

[Jeff Cochrane - VK4BOF]

Further info:
This is the second time I have mentioned / bitched / whinged about this issue in this list and I have finally found the problem, read on.

After a year of looking (and bitching) about my voltage drop issues, in sheer desperation I took a look at the K3's connectors and finally solved the riddle of my missing volts! 
(And it was volts at one stage, on a 20A load current I would see a 1.5 to 2 volt drop @ 13.8V - 20Amp current draw indicated by the radio!)
The original voltage drops mentioned above were seen with the factory built power lead and radio right from when I got the K3 in May / June 2010.

At that time they were just dismissed as "being an anomaly in the rigs own measurement capabilities" or a "problem with the power supply" but on checking the power supply and finding it to be in good health, measuring the actual voltage drop and then speaking with other K3 owners I realised that there was an issue somewhere.

The original lead was ditched not long after I was made aware the voltage drops were too high and the current (pun intended) power lead for the radio is a newly self made 6mm dual core cable fitted with soldered 30A Anderson Powerpoles at one end with soldered 4mm lugs at the other end to suit my power supply. The new power cable is approximately 36" (1 Metre) long. (I don't believe in or use crimped connections as a rule)
This improved things to the point where I was seeing a voltage drop of generally around 1.2Volts at 13.8V - 20A current draw. 
(A useful improvement over the 2 volt drop I had seen before) :-)

I put up with this loss for some time but I finally got around to looking harder at the issue last night.

Upon further investigation I found that the problem was with the connectors that are fitted to the K3's motherboard, which is what had me flummoxed, the rig is just on a year old and I didn't even think to consider that the onboard connectors could be dodgy for one minute. (Just goes to show you, never discount anything unless you test it!)

Once the contacts were cleaned (First by cleaning with a cotton bud dipped in thinners and then when that didn't work by scraping the contacts in the radios connector with a small screwdriver then burnishing with a small file) the voltage drop has been within 0.2 - 0.3V @ 4A current draw and *0.5 - 0.6V at 20A draw. (That is a 28MHz 100W FM carrier into a 1.0:1 VSWR dummy load).

* (All voltage drops shown here are measured at 13.8V supply voltage and are as shown by the rig itself, the measurements shown are in fact a little higher than they actually are due to internal voltage drops etc in the K3.)

Now I realise that according to Anderson the connectors are supposed to be self cleaning, but my experience so far with them has demonstrated otherwise. 
In that case it may be wise to check the connectors fitted to your rig / cable occasionally, I 'sure as sh1t' will be from now on. (Until I ditch them all)

Of course, none of all the above raises my opinion of Anderson PowerPoles one iota, I don't believe that they are a particularly good idea, especially for a radio that is designed to be in used more in a portable situation far more than any other radio and given the hassles I have had with the damned things, if I could I would gladly ditch then from the back of my K3 in an instant.

What would I use in their place?

A pair of 6mm wires, permanently soldered to the motherboard and fitted with a strain relief, voltage drop problems solved!

73 de
Jeff Cochrane - VK4BOF
Innisfail, QLD, Australia
Elecraft K3 #4257 + KPA500 + PR6 + K144XV = Multiband greatness!

  ----- Original Message ----- 
  From: David Ferrington, M0XDF 
  To: elecraft at mailman.qth.net 
  Sent: Wednesday, May 18, 2011 6:44 PM
  Subject: Re: [Elecraft] Anderson Powerpole voltage loss


  I have never found dirty APPs - the whole idea is that they wipe each other as joined and unjoined.
  This suggests a badly fitting contact in the housing.
  73 de M0XDF, K3 #174, P3 #10873 de M0XDF

  On 18 May 2011, at 09:29, Gary Gregory wrote:

  > The gentleman also discovered the contacts were "dirty", after cleaning they
  > showed normal and expected voltage...:-)

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