[time-nuts] HP 105B: Modern replacement for NiCad battery pack?

[Van Horn, David]

Nicads are still made.

NIMH is not necessarily a drop in. While it will work fine in the short term, crude chargers that implement constant trickle like C/10 can be (emphasis) tolerated (/emphasis) by some NIMH cells, and totally out of spec for others.

Modern chargers and NIMH is a good pairing, but if you must use the original NICAD charger, you likely need real NICADs for a long term solution.


-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of paul swed
Sent: Friday, January 5, 2018 10:00 AM
To: Ulf Kylenfall; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

Ulf
A drop in replacement for nicads is nickle metal hydride or NiMh. Nicads are still available but can be expensive.
The other comment I would make is the 1970s charging circuits were pretty crude and lead to boiled batteries.
If your going to invest in an internal battery you may want to consider a smarter modern charger.
There seems to be all sorts of very nice boards out of China for little cost. Its amazing.
If you go the alternate approach you may consider Lithium batteries.
Drones seemed to have made a very nice market for batteries and smart chargers.
Regards
Paul
WB8TSL

On Fri, Jan 5, 2018 at 11:46 AM, Ulf Kylenfall via time-nuts < time-nuts at febo.com> wrote:

>
> Gentlemen,
> I may have asked this question before...
> I am looking for a modern replacement for the NiCadbattery pack used 
> in the HP 105B. One such 105that I salvaged have been standing on a 
> shelf with thebatteries "happily boiling away".
> So, what kind of chemistry would be possible to usewithout to much 
> re-design of the charging circuitry?
> Ulf Kylenfall
> SM6GXV
>
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