[time-nuts] HP-105B Battery Replacement?

Brooke Clarke brooke at pacific.net
Thu Sep 15 12:59:15 EDT 2016


Hi Jeremy:

I'm currently having fun playing with various rechargeable battery related stuff  which includes Li-Ion cells.
http://www.prc68.com/I/BatTst.shtml#Resistor
The cells come in three configurations:
1. the raw flat top cell with optional tabs to allow easy soldering into a pack,
2. cell plus positive button cap which includes a Positive Temperature Coefficient (PTC) fuse and an over pressure vent,
3. fully protected, like 2, plus circuit that turns off the battery if charging and over voltage or loaded and under 
voltage.  On these you can feel a wire/ribbon running from positive to negative under the shrink wrap and they are 
slightly longer.
These configurations are independent of the flavor of Li chemistry.

To go with any of the above you need a charger specific to the particular Li chemistry (the charging voltage is not the 
same) and if a pack you also need a either cells like 3 above or a protection circuit for the pack.  For optimum 
performance in addition a tap between each virtual cell (made of of parallel cells) so that the charge can be balanced 
and a charger that can do that.  This is not easy, witness the current recall of the Galaxy Note 7s phones.

I would just use modern Ni-Cad cells mainly because of the ease of charging and maintaining them and use the existing 
charging circuitry.
Li chemistry has advantages for portable equipment, but not so much for rack mounted equipment.

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

-------- Original Message --------
> Thanks, Brooke, I'll price new Ni-Cads. I wasn't thinking of lead-acid (gel
> cells) but rather lithium rechargeable, providing I can find a type that
> won't catch fire and will work with the 105B'scircuits.
>
> Jeremy
>
>
> On Wednesday, September 14, 2016, Brooke Clarke <brooke at pacific.net> wrote:
>
>> Hi Alex:
>>
>> Yes, I'm recommending Ni-Cad but NOT any acid type.
>>
>> --
>> Have Fun,
>>
>> Brooke Clarke
>> http://www.PRC68.com
>> http://www.end2partygovernment.com/2012Issues.html
>> The lesser of evils is still evil.
>>
>> -------- Original Message --------
>>
>>> Hi Brooke,
>>>
>>> sorry I have to disappoint you; Ni-Cd batteries do not use any acid, they
>>> have K-OH  kalium hidrioxid  [potassium hydroxide  for anglophone ] as
>>> electrolyte and they are normally very air-tide, and widely used in radios.
>>>
>>> 73
>>>
>>> KJ6UHN
>>>
>>> Alex
>>>
>>> On 9/14/2016 4:45 PM, Brooke Clarke wrote:
>>>
>>>> Hi Jeremy:
>>>>
>>>> It's a very bad idea to put any battery with acid in an enclosure that
>>>> has electronics since if it vents the acid will etch the PCBs.
>>>> Guess how I learned this.  I got a great price on a Gibbs Frequency
>>>> Standard because the oven no longer worked.
>>>> http://prc68.com/I/office_equip.html
>>>>
>>>>
>>>> Modern Ni-Cad batteries have much more capacity than older ones and no
>>>> longer have a memory effect.  They are also very easy to charge, so why not
>>>> just replace the old cells?
>>>>
>>>>
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>




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