[Elecraft] KXBC3 charging schedule for self discharge

[Greg Troxel]

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Mike WA8BXN <hubby2k at hotmail.com> writes:

> I have a set of Maha 2700 mAh NiMH batteries in my KX3. Its used mostly with
> a 14.4 V power supply. The instruction sheet for the KXBC3 indicates
> batteries typically self discharging 2% per day. What would be a good
> charging plan (how often/how many hours) to keep the batteries reasonably
> charged and maximize battery life? For example, every 2 weeks for 8 hours?
> Once a week for 4 hours?

My three suggestions:

  1) every 2 weeks, 4h.  measure voltage PER CELL before doing this, and
  if it's at least 1.3, don't worry too much.  Remind yourself that
  without instrumentation you don't really know what's going on.  Think
  about getting a MAHA C9000 :-)

  2) buy a MAHA C9000.  Charge the batteries.  Let them set for 2 weeks.
  Charge them at 200 mA and see what they need.  Note that they are
  probably not even.  If they are, you have your answer.  If not,
  proceed to worry or #3.

  3) Set those aside and get some 2100 mAh imedions.  If you are really
  not using them the daya after they are charged, you should be using
  low-discharge batteries.  With the imedions, buy a C9000 also, and
  charge them, wait two weeks, and do a test discharge.  Decide to give
  them 8h every 3 months and not worry.

(For those wondering, I have no connection with maha/powerex/thomas).
But having been able to measure charge into a battery (in mAh) and do
discharge measurements, I can't imaginge going back.)

73 de n1dam