[Elecraft] kx3 internal batteries question

[Richard Gagnon]

Hi Greg,
Really appreciate the detailed instructions! Still waiting for my 9000
and new Enloops, but I will follow these recommendations as soon as it
arrives. I didn't even think of the importance of Low Discharge verses
the high Ah rating, but it is clearly an important parameter.
Rich

-----Original Message-----
From: Greg Troxel [mailto:gdt at lexort.com] 
Sent: Sunday, October 20, 2013 8:29 AM
To: Richard Gagnon
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] kx3 internal batteries question

  I then removed all 8 batteries and checked their voltage (no load,
just
  with an old Simpson VOM) and 4 batteries measured 1.2 V and the other
4
  were at 0.0 V. I am not sure why they would be different, nor do I
  understand the BATT ERROR message. 

[Others have explained BATT ERROR.]

It sounds like 4 of the batteries are weak and/or failed relative to the
other 4.  Are they really the same kind and age?

I usually advise against buying batteries that are 1) not
ultra-low-discharge or 2) other than Maha/PowerEx or Sanyo.

First, label the 8 batteries with something that won't rub off.  Also
label your new 8 batteries.  Log the as-found voltages, and all of the
following data.

Eventually you will have weak/bad cells, and it's really hard to know
what's going on if they aren't labeled.  With a set of 8, you will need
to get 8 new ones when you have one failure, but you will likely have a
number of cells that can be used in pairs.  (I got 8 Maha Imedions in
2009, and have been using them nearly daily to power a handheld GPS
receiver.  6 are working fine, and 2 have failed, which seems ok given
their usage.)



When your C9000 arrives (that spares me from advising that you get one
:-), do a REFRESH-ANALYZE cycle on each battery.  I use 1000 mA charge,
200 mA discharge, as a standard load over multiple devices.  After
you've
done all 8, do them again.   If some are weak (not 100 mA less, but like
700 mAh vs 2400 mAh), they are bad and should be recycled.

Also do refresh-analyze on the new batteries, 2 cycles.  Probably they
will stabilize in capacity on the 2nd cycle, with values not that
different than the first.  Keep this data so you can do it again every
year.

Feel free to send me the data offlist for interpretation.

My extended battery ranting is at
  http://www.lexort.com/blog/12v.html

73 de n1dam