Re: Unusual Challenge

[RTS <gafa@xxxxxxxxxxxxx>]

On 1/12/2022 9:12 PM, John R. Sowden wrote:
> Could you please advise how you got a 60% reading on a cr2032 lithium
> battery.  When I replace a battery on a wireless job, it was my
> understanding that there is no test for a life of a lithiom battery.
>
> John Sowden
> American Aentry
> SF Bay Area
> jsowden@xxxxxxxxxxxxxxxxxx
>
> On 10/20/21 5:31 PM, ABLE1 wrote:
>> Hey Guys,
>>
>> Would like some thoughts on the following challenge.
>>
>> Customer has a showroom/office in one building and the shop in another
>> that is 70 feet away.  They wanted to have a way to get notified in the
>> shop that a potential customer came into the showroom.
>>
>> What I installed was a door contact switch on the entry door and wired
>> a Linear DXT-31 transmitter and a Linear DXT-701 Receiver in the shop.
>>
>> Â From there I used the contacts on the receiver to trigger and Altronix
>> timer and the contacts there to trigger a horn/buzzer for about 1 sec.
>> when the door was opened.
>>
>> It has worked quite well for some time but, recently I was told that
>> it did not respond to ALL entering the showroom.
>>
>> I was there a couple of weeks ago and it was working but the the CR2032
>> batteries were about 60% level and I changed to new.  Tested the
>> batteries were at 100%. OK.
>>
>> I was then informed yesterday that it was still missing some entries.
>>
>> I stopped in today and first I tested the door 3 times and it did not
>> work.
>>
>> I tested the batteries.  They were at 100%
>>
>> I removed the transmitter and went to the shop and it worked 5 times
>> in a row.  Or let's say 100%  I put the transmitter back in the attic
>> above the showroom where it was but staff was in a meeting so I could
>> not test.
>>
>> Was told later that they tried it and it did not work a total of 3 times
>>
>> Now the receiver has a wire about 7" long as a antenna.  I have
>> it hanging over the edge of a window so that the walls would not block
>> the RF signal. The Transmitter is in the attic space on a vertical
>> 2x4.  The only thing that might block the signal would be the plywood
>> and asphalt shingles on the roof, 70' of distance, bug screen and
>> glass window.
>>
>> Needless to say this is a intermittent problem that is NOW not working!!
>>
>> So, any thoughts on this before I type something that really made a
>> difference this afternoon.
>>
>> Thanks for any thoughts!!
>>
>> Les
>
Whenever I have a need to check the current status of a battery,
I use a static resistance load..
First you need the discharge rate sheet from the manufacture.
Then a meter to read the static voltage on the cell
Second another meter to read the current from battery to load
Third a rated load (resistor) I use different resistors to make up
the discharge current as listed on the manufacturers discharge sheet.
(take care to use a high enough wattage rating on your resistor)

Then just add the load to the battery and monitor the discharge
rates on the meters..
Compare your reading with the manufacturers sheet..  ;-)

you can do the same thing using the device as the load..
giving you a better idea of battery life expectancy ...

Isn't that fun.. ?
RTS
--

*Rocky T. Squirrel, esq.*