L
les
hello...
I have an atomic wristwatch that after a year or so acted like the battery
was worn.
Specifically, the EL backlight (when depressed) would cause the numerics to
momentarily blank, and the clock to default to noon.
After replacing the battery, it seemed fine for a few days, and the symptoms
returned. Not suspecting anything, I bought a replacement watch by another
company (it had a different marking) but worked identically. Again the year
went
by and the story was the same. I bought the CR1620 at Walmart, and even
replaced that one within a week, and had this identical problem.
So this brings me now here.
I measured the current in 3 states:
quiescent: 3 uA, actively radio syncing: 180 uA, EL backlight : 5mA
When I used a AA 3 volt pack, the issue disappeared. Eveything was fine.
I suspect the current draw essentially drops the voltage below a theshold,
reseting
the watch. But is this normal? Can a lithium button cell be expected to
sustain
a 5mA draw momentarily and not reset a watch? Or am I constantly finding
poor quality lithium cells?
Suggestions? Perhaps a source for "good" button cells?
Les KA9GLW
I have an atomic wristwatch that after a year or so acted like the battery
was worn.
Specifically, the EL backlight (when depressed) would cause the numerics to
momentarily blank, and the clock to default to noon.
After replacing the battery, it seemed fine for a few days, and the symptoms
returned. Not suspecting anything, I bought a replacement watch by another
company (it had a different marking) but worked identically. Again the year
went
by and the story was the same. I bought the CR1620 at Walmart, and even
replaced that one within a week, and had this identical problem.
So this brings me now here.
I measured the current in 3 states:
quiescent: 3 uA, actively radio syncing: 180 uA, EL backlight : 5mA
When I used a AA 3 volt pack, the issue disappeared. Eveything was fine.
I suspect the current draw essentially drops the voltage below a theshold,
reseting
the watch. But is this normal? Can a lithium button cell be expected to
sustain
a 5mA draw momentarily and not reset a watch? Or am I constantly finding
poor quality lithium cells?
Suggestions? Perhaps a source for "good" button cells?
Les KA9GLW