[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...

Bob Camp kb8tq at n1k.org
Sun Nov 2 16:20:30 EST 2014


Hi

It’s those little onboard batteries that I have the experience with. After a while, you are doing well to get a month out of them. Play for a bit longer and they are down to a couple weeks. That’s not a surprising thing, the charging circuit on some of this stuff is often less than perfect. You get a lot of cycles / long life out of a properly handled battery. Abuse the poor thing and not so long a life.

Bob

> On Nov 2, 2014, at 4:12 PM, GandalfG8--- via time-nuts <time-nuts at febo.com> wrote:
> 
> Ah, just found an Engineering Note in my files that again quotes 5uA at  
> 2.5V but also quotes 100uA at 5.0V, perhaps not too relevant at 3.1V but 
> that's  quite an increase.
> 
> The same document quotes the following specs for the optional onboard  
> lithium battery...
> 
> Voltage -- 3V
> Capacity -- 15mAh
>                  approximately  3 months between charges
> Recharge -- approximately 8 hours for a full charge
> Lifetime -- 5 Years minimum.
> 
> So I guess an onboard battery conversion might still be a viable  option.
> 
> Regards
> 
> Nigel
> GM8PZR  
> 
> 
> In a message dated 02/11/2014 21:01:55 GMT Standard Time, kb8tq at n1k.org  
> writes:
> 
> Hi
> 
> So then the question becomes - What is the real cutoff  voltage?
> 
> Your pair of AA’s will start off at 3.1V, but they will get to  2.5 long 
> before they are truly dead. Is the RAM gone at 2.5000 or 2.4 or  “about 2 volts
> ” ….
> 
> Bob
> 
>> On Nov 2, 2014, at 3:54 PM,  GandalfG8--- via time-nuts 
> <time-nuts at febo.com> wrote:
>> 
>> Hi Bob
>> 
>> The UT+ data sheet from 1998 quotes an external backup  supply of 2.5 to  
>> 5.35V with a drain of 5uA typical at 2.5  Volts.
>> 
>> Regards
>> 
>> Nigel
>> GM8PZR
>> 
>> 
>> In a message dated 02/11/2014 20:41:44 GMT Standard Time,  kb8tq at n1k.org  
>> writes:
>> 
>> Hi
>> 
>> The  numbers quoted earlier (and they sound right) were 20  uA at 2.5V. 
> That  
>> would be well under your 100uA. My *guess* is that self   discharge / 
> aging 
>> on a normal AA is going to limit things faster than  a 20 uA  drain. 
>> 
>> Now, if you have the more normal tiny  coin cell involved  with  1/10 or 
>> 1/100 that capacity and  much lower self discharge  ….
>> 
>> Bob
>> 
>>> On Nov 2, 2014, at 3:17 PM, Hal Murray  <hmurray at megapathdsl.net>  
> wrote:
>>> 
>>>> By the way the  z3801 is off most of  the year so the drains quite 
> small.
>>> 
>>> I  think  that's backwards.  The battery is only used when there is no 
>> power  to 
>>> the GPS module.
>>> 
>>> AAs are  roughly 2800 mA  hours.  There are 8760 hours in a year.   
> That's 
>> 319 
>>> microamp years.  (How's that for a SI  unit?)  So that's 3 years if  
> your 
>> GPS 
>>> module  takes 100 uA.  I think that's way high.   Anybody measured  it?  
>> There 
>>> is probably a strong temperature   component.
>>> 
>>> 
>>> -- 
>>> These are my  opinions.   I hate spam.
>>> 
>>> 
>>> 
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