[Elecraft] OT Battery question

Fri May 21 21:27:03 EDT 2004

I have this problem also with my Maha, but not all of the time. I believe
Maha states that you shouldn't charge only 2 batteries, but rather at least
3 or 4 cells at time.  The heat sensor, only seems to kick in when the
batteries are very warm to the touch.

I seem to lose batteries before they have a chance to get ruined, I guess
that makes this a moot point in my case...hi

Tom WB2QDG

----------------------------------------------------------------------------
----------------------
One thing I don't like about this country is that everyone gets to have his
own opinion on things!
-----Original Message-----
From: bprats at telis.org <bprats at telis.org>
To: 'Don Brown' <DolfinDon at msn.com>; 'Elecraft' <elecraft at mailman.qth.net>;
'Vic Rosenthal' <vic at rakefet.com>
Date: Thursday, May 20, 2004 8:29 PM
Subject: RE: [Elecraft] OT Battery question

Although the Maha 777 plus series seems very good, I would take Maha to task
that it ruins a lot of batteries because it charges too fast, causing
extreme heat and venting.  Ask your battery supplier for their opinion.

I would recommend leaving the NI / LI switch in the LI position because this
position limits the maximum current but I notice the 10 cell AA charge
voltage is 12.5 when "FULL" and not 14.5 as is with the NI setting.  This
info is in the  777 Plus manual.  The Maha must be OFF / ON for the switch
setting to take affect.

Other than that, I'm told a simple series resister is not the answer, maybe
someone who is familiar with the microprocessor control and regulator can
help.

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Don Brown
Sent: Thursday, May 20, 2004 3:21 PM
To: Elecraft; Vic Rosenthal
Subject: Re: [Elecraft] OT Battery question

Hi

All fast chargers will cause the batteries to get quite warm, but not so hot
that it is uncomfortable to touch the batteries. There are some chargers
that overdo it. The so called 1 hour chargers are the ones that are the
problem. This is just a little too fast for a AA cell. I have tried a lot of
chargers but the Maha 401 is the best I have found for AA and AAA cells.
This charger has slots for 4 cells AA or AAA in any combination. Each slot
is independent so the charge is monitored on each cell rather than several
in series. It has a fast mode that will charge a set of 2000 mA hr cells in
about 100 minutes or a slow mode that will charge them in about 4-5 hours.
When the charge is complete the charger switches to a trickle mode of 50 ma
per cell to top them off. This charger seems to put the most power back into
the batteries without overheating the batteries. It uses a delta V pulsed
charging algorithm. It cost about $35 and comes with a set of 2000 ma
batteries or you can buy it alone for about $25. There is also a 12 volt
cable for the car.

For larger battery packs the best I have found is the Maha 777+ This charger
will handle battery packs of just about any size or any voltage up to about
16 volts automatically. It has an innovative connector that allows it to
connect to just about any configuration on the pack and it will determine
the proper charge voltage and polarity. It can cycle a pack and will display
the mA Hr input to the battery on a digital display. It will also charge
LiOn type batteries as well as NiCad and NiMh batteries.

Don Brown

  ----- Original Message -----
  From: Vic Rosenthal<mailto:vic at rakefet.com>
  To: Elecraft<mailto:elecraft at mailman.qth.net>
  Sent: Thursday, May 20, 2004 4:53 PM
  Subject: [Elecraft] OT Battery question

  I have a battery charger for NIMH aa cells.  I charge NIMH aa cells in
  it, as you are supposed to do.  The cells get very hot (too hot to touch
  for more than a few seconds) when charging, and the charging process
  takes only a few minutes.

  My feeling is: this can't be good.  Should I look for a slower, more
  gentle, charger (recommendations?)  Or is this the way NIMH cells are
  supposed to work?

  --
  73,
  Vic, K2VCO
  Fresno CA
  http://www.qsl.net/k2vco<http://www.qsl.net/k2vco>

  _______________________________________________
  Elecraft mailing list
  Post to: Elecraft at mailman.qth.net<mailto:Elecraft at mailman.qth.net>

http://mailman.qth.net/mailman/listinfo/elecraft<http://mailman.qth.net/mail
man/listinfo/elecraft>
  You must be a subscriber to post.
  Elecraft web page: http://www.elecraft.com<http://www.elecraft.com/>
_______________________________________________
Elecraft mailing list
Post to: Elecraft at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/elecraft
You must be a subscriber to post.
Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: Elecraft at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/elecraft
You must be a subscriber to post.
Elecraft web page: http://www.elecraft.com