Tandy Service ManualAgreed.

There are some differences between NiCd and NiMH charging recommendations, but 
according to the Panasonic literature the standby Trickle charging currents are 
exactly the same.

  ----- Original Message ----- 
  From: Fugu ME100 
  To: m...@bitchin100.com 
  Sent: Monday, March 12, 2018 4:21 PM
  Subject: Re: [M100] batteries...

  Where is that stated about Trickle Charging,  I don’t see it in the M102 

  I can find the section on pg 1-7 where it says "Charging current 1.2mA 
(typ)".   Which is in line with an average current however it will vary 
considerably depending on charge state of the battery.  Fully charged the 
current will be 300uA it cannot be more.   

  So the impact will be well below any but the worst quality batteries – which 
may have other issues :) 

  From: M100 <m100-boun...@lists.bitchin100.com> on behalf of George Michael 
Rimakis <grima...@gmail.com>
  Reply-To: <m...@bitchin100.com>
  Date: Monday, March 12, 2018 at 12:11 PM
  To: <m...@bitchin100.com>
  Subject: Re: [M100] batteries...

    The M102 service manual says the trickle charge is at 1.2mA, and some 
batteries may not be as tolerant.

    On Mon, Mar 12, 2018 at 3:54 PM, Fugu ME100 <b4me...@hotmail.com> wrote:

      I swapped to NiMH for my replacements mainly because NiCd was hard to 
find.  Before doing so I did some research on manufacturer recommendations.  
This doc is pretty good 
http://data.energizer.com/pdfs/nickelmetalhydride_appman.pdf  If you look at 
the Recommended Charging Rates section (pg 11) it gives this recommendation on 
trickle charging:

      'Finally a maintenance (or trickle) charge rate of less than 0.025C 
(C/40) is recommended. The use of very small trickle charges is preferred to 
reduce the negative effects overcharging.’

      The NiMH and NiCd self-discharge very badly so if the trickle charge < 
self discharge rate things should be fine.  

      Looking at the charge circuit on the M100 it is basically a series diode, 
resistor (1.8K) and the battery.  If the battery is at 0V the max current is 
~2mA,  at full charge (3.7V) the current is ~300uA.   Based on the 
recommendations of Energizer the charge should be <C/40 for a trickle charge. 
The battery is ~60mAh, which gives ~1.5mA trickle or maintenance charge well 
above that produced in the M100, in fact the NiMH might sell discharge at that 
rate.   So I went ahead and updated the batteries.  

      If you trickle charge at very high rates then NiMH might fail earlier but 
so too would NiCd.   The initial charge might be slower for NiMH compared to 
NiCd but that is not really an issue in this application it is merely acting as 
a backup battery.  

      From: M100 <m100-boun...@lists.bitchin100.com> on behalf of George 
Michael Rimakis <grima...@gmail.com>
      Reply-To: <m...@bitchin100.com>
      Date: Monday, March 12, 2018 at 10:10 AM
      To: <m...@bitchin100.com>
      Subject: Re: [M100] batteries...

        The thing about NiMH, is the level of trickle charge that they can 
tolerate is a bit less than NiCD. Might not be good in the long run.

        On Fri, Mar 9, 2018 at 5:00 PM, Jim Anderson <jim.ander...@kpu.ca> 

          > -----Original Message-----
          > This brings up an interesting point.  Having just replaced my NiCad 
          > think I'm going to use my label maker to leave a note about when it 
          > replaced under the battery door.

          I like to do this anyway (and not just with m100s), because I find 
myself struggling to remember later which machines have which things replaced, 
and when they were done...


Reply via email to