[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...
Bob Camp
kb8tq at n1k.org
Sun Nov 2 21:20:30 UTC 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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