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

Bob Camp kb8tq at n1k.org
Sun Nov 2 16:01:52 EST 2014


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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