[K3] Real Time Clock Battery replacement

[Geoffrey Downs]

In the next few days I’ll be taking apart my trusty K3 #266 to install K3SYNAs and do KBPF3 mods. As it’s seven and a half years old I could also replace the clock battery while I have it exposed or I could leave it to see how long it keeps going. Has anyone’s K3 clock battery run down yet? Any views on how long it should last?

73 to all,

Geoff
G3UCK
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[Matt Zilmer-3]

Hi Geoff,

I have a K3 of similar vintage.  When I upgraded to KSYN3As, I just
replaced the coin cell while it was exposed with the sub-RX removed.
At the time I replaced it, the cell was still going strong.

Most of the CR series coin cells from around 2007 survive on the order
of 10 years (shelf life).  I think that this lifetime is generally
longer now, but it varies by manufacturer.  The cell I put in was
rated to be good until 2025.

I've used CR series cells in applications where they lasted 15 years.

73,
matt
W6NIA

On Sat, 18 Jul 2015 18:28:49 +0100, you wrote:

>In the next few days I’ll be taking apart my trusty K3 #266 to install K3SYNAs and do KBPF3 mods. As it’s seven and a half years old I could also replace the clock battery while I have it exposed or I could leave it to see how long it keeps going. Has anyone’s K3 clock battery run down yet? Any views on how long it should last?
>
>73 to all,
>
>Geoff
>G3UCK
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>Elecraft mailing list
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Matt Zilmer, W6NIA
--
"Always store beer in a dark place."  -R. Heinlein

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[Phil Wheeler-2]

No data here, Geoff; my K3 is only about 15 months
old.

Likely irrelevant but the battery in my old
TS-570DG was over 15 years old and still working
when I replaced that battery a year ago.  But the
TS-570 was little used after I built my K2
starting in 1999 (which then became my primary rig
until last year).

73, Phil W7OX

On 7/18/15 10:28 AM, Geoffrey Downs wrote:
> In the next few days I’ll be taking apart my trusty K3 #266 to install K3SYNAs and do KBPF3 mods. As it’s seven and a half years old I could also replace the clock battery while I have it exposed or I could leave it to see how long it keeps going. Has anyone’s K3 clock battery run down yet? Any views on how long it should last?
>
> 73 to all,
>
> Geoff
> G3UCK

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[Vic Rosenthal]

I have K3 serial number 7 and I forgot it had a realtime clock or the
last time I set it. It is off about 30 seconds now.

73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/

On 18 Jul 2015 20:28, Geoffrey Downs wrote:
> In the next few days I’ll be taking apart my trusty K3 #266 to
> install K3SYNAs and do KBPF3 mods. As it’s seven and a half years old
> I could also replace the clock battery while I have it exposed or I
> could leave it to see how long it keeps going. Has anyone’s K3 clock
> battery run down yet? Any views on how long it should last?
>
> 73 to all,
>
> Geoff G3UCK
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It all depends on the RTC current.  A nice graph of expected life vs current (uA) for a number of CR cells is in http://www.varta-microbattery.com/applications/mb_data/documents/sales_literature_varta/HANDBOOK_Primary_Lithium_Cells_en.pdf

I had my K3 for 3 yrs when I upgraded the synth cards and I did replace the CR2032 on general principle.

Cheers
Rick AG6AY