CR2025 question (update)

[Stream]

[Well, it happened again with the new battery. So I think that rules out the old battery as the fault. The IC of the watch just seems to be defective somehow. It works most of the time, though, but I just can't rely too much on this watch]

At what voltage would you say a CR2025 3v lithium coin cell is depleted? This is a watch battery for a Casio wrist watch, and the display would occasionally fade out but then come back if you pressed a button. The display and the display light was not dim at all, except when it was fading out. I just swapped out the battery for a new one. The new one read 3.3v and the old one read 2.9v. The watch is supposed to run ten years on one batter, and I've only had it about a year. I bought it on ebay (New according to seller) and it was cheap so I thought would just change the battery and be done with it. But now I'm wondering if the battery was the problem. If you guys think 2.9v sounds like a weak battery then I guess problem solved. If not then i will just have to wait and see if the problem returns with the new battery, in which case I guess the watch may have another defect :shrug:

 

[Dan FO]

Re: CR2025 question

2.9V is weak for a Casio watch. Maybe it was a bad battery to begin with. If the watch has a PS (power saver) feature, turn it on. The battery life is calculated using the the display once per day.

 

[davidefromitaly]

Re: CR2025 question

the problem is the watch, is a series of modules that have a high fail rate, buy another one...

i have see good working casio digital watches run also with a 0.8V supply

 

[Stream]

Re: CR2025 question

the problem is the watch, is a series of modules that have a high fail rate, buy another one...

i have see good working casio digital watches run also with a 0.8V supply

The watch is a Casio AQ-180W (module nr. 3793). It's the type with an analog face with two hands and a small digital display at the bottom. So if I understand you correctly, many of these cheap Casio watches are very prone to failure. Correct? I always considered Casio to be a decent brand, even the cheaper watches. But I guess it makes sense that the problem could be the watch and not the battery when it shows 2.95v and the watch is experiencing problems. I'm gonna see if the problems show up again with the new battery, but it took a year before I started seeing problems with the last battery.

If I get another watch I guess I will stay clear of Casio, a least the cheap ones. What other brands would you recommend for cheap or moderately priced watches?

 

[Dan FO]

Re: CR2025 question

These are bullet proof. Probably the most popular military combat watch out there, they have a NSN and are certified by NASA for space flight.

http://en.wikipedia.org/wiki/DW-5600E

 

[Burgess]

Re: CR2025 question

to Dan FO --


Wow !

Thank you for that Link :thumbsup:


Very interesting stuff.

:twothumbs

_

 

[Dan FO]

Re: CR2025 question

Except for the Casio Frogman series this is my favorite of the Casios --> http://www.casio.com/products/Timepiece/G-Shock/GW5600_Series/product/GW5600J-1/

 

[kitelights]

Re: CR2025 question

The watch is a Casio AQ-180W (module nr. 3793). It's the type with an analog face with two hands and a small digital display at the bottom. So if I understand you correctly, many of these cheap Casio watches are very prone to failure. Correct? I always considered Casio to be a decent brand, even the cheaper watches. But I guess it makes sense that the problem could be the watch and not the battery when it shows 2.95v and the watch is experiencing problems. I'm gonna see if the problems show up again with the new battery, but it took a year before I started seeing problems with the last battery.

If I get another watch I guess I will stay clear of Casio, a least the cheap ones. What other brands would you recommend for cheap or moderately priced watches?

In spite of the good information that you've received here, if you like the watch and it will run for a year on a cell, you can buy ten 2025 cells for $5-10 online (maybe less). Change the cell once a year and enjoy the watch.

 

[davidefromitaly]

Re: CR2025 question

In spite of the good information that you've received here, if you like the watch and it will run for a year on a cell, you can buy ten 2025 cells for $5-10 online (maybe less). Change the cell once a year and enjoy the watch.

well isn't a good reason... first of all if a battery is declared to last 10 years i can accept 7-8 but 1-2 isn't fine. and at 2.95V the battery is quite charged, so there is a problem in the watch. i have some old casio, with a 90mAh battery they last 5-7 years, now the watch of stream use a 165mAh and last only 1-2 years? there is a problem...

The watch is a Casio AQ-180W (module nr. 3793). It's the type with an analog face with two hands and a small digital display at the bottom. So if I understand you correctly, many of these cheap Casio watches are very prone to failure. Correct? I always considered Casio to be a decent brand, even the cheaper watches. But I guess it makes sense that the problem could be the watch and not the battery when it shows 2.95v and the watch is experiencing problems. I'm gonna see if the problems show up again with the new battery, but it took a year before I started seeing problems with the last battery.

If I get another watch I guess I will stay clear of Casio, a least the cheap ones. What other brands would you recommend for cheap or moderately priced watches?

i never hear problems with the 3793 module... instead a lot of tought-solar with the CTL1616 battery had problems (now solved i think) and some very cheap 2963 module

your problem with the 3793 is really similar to the one happend to the 2963 series but for now i can't say if is a unlucky watch or is a diffused problem

for sure, at 2.95V your watch must run, otherwise there is a problem. when the battery is really discharged the display dim when you use the alarm or the backlight, this mean that the voltage is under 2V around

 

[kitelights]

Re: CR2025 question

First of all, open voltage testing on these cells means nothing. I just tested a 'new' unused older cell that I have from a batch that I determined was not up to par and it read 3.25V and tested 0 on my ZTS.

So, to start with, as someone already suggested, the cell that came in the watch may not have been up to par to start with. Is the watch now working properly and was the 'new' cell known to be a good cell? Open voltage testing doesn't guarantee that it is.

The next major issue, again as someone has already said, is that the battery life is calculated using the display once a day. If you're using the display 10 times a day, that's an easy way to cut off 9-10 years of life.

There very well may be a problem with the watch. Others that seem to be in the know have commented that there is a known problem with that model.

My point is that it hasn't yet been determined that the cell is not dead.

 

[davidefromitaly]

Re: CR2025 question

First of all, open voltage testing on these cells means nothing. I just tested a 'new' unused older cell that I have from a batch that I determined was not up to par and it read 3.25V and tested 0 on my ZTS.

just for complete: this kind of watches drain something like 2 micro-amps average, less than 1 uA most of time, around 20 uA when the analog clock pulse, around 0,8 mA when the alarm sound or the light is on

this will help you to simulate the drain and see how much the voltage drop

 

[Stream]

Re: CR2025 question

First of all, open voltage testing on these cells means nothing. I just tested a 'new' unused older cell that I have from a batch that I determined was not up to par and it read 3.25V and tested 0 on my ZTS.

So, to start with, as someone already suggested, the cell that came in the watch may not have been up to par to start with. Is the watch now working properly and was the 'new' cell known to be a good cell? Open voltage testing doesn't guarantee that it is.

You know, I was thinking the same thing, but I don't have a device to test the battery under load. I just have a regular volt meter. The only thing that makes me kind of doubt that the battery was bad is that the display was not dim at all, and it would not dim when I activated the backlight or when I used the alarm. It would only occasionally dim and/ or fade out completely - one time to the point where I had to reset the digital display clock.

Another fact that I'm not sure if I have mentioned before is that the two first times it happened (it has happened a total of 3 times that I have been able to observe) the watch went from cold to room temperature environment. The first time I had it with me when I was outside exercising and the temp must have been around 23F (-5C), and when I went back inside to where the temp was probably around 68F (20C) the display started to dim. The second time was when I went from room temp to outside when it was a little warmer outside (probably around 41F / 5C) - that's when it went completely dead until I pushed a button, then the display came back. The third time was in room temperature and the watch had been indoors for several hours, and i actually think it dimmed when I pushed a button (that's the only time it dimmed when I pushed a button). So that's why I'm not sure if the temperature thing is relevant. I tried recreating it several times by bushing the buttons, and activating the backlight repeatedly, as well as using the alarm lots of times, but nothing seemed to make the display dim or even flicker a little.

The new battery was factory sealed and unused. Of course that doesn't necessarily guarantee that the new battery is good, but so far I have not seen the display fade out again. Time will tell, I guess.

The next major issue, again as someone has already said, is that the battery life is calculated using the display once a day. If you're using the display 10 times a day, that's an easy way to cut off 9-10 years of life.

By using the display, do you mean using the backlight or alarm? This watch does see a lot of use, I use the stopwatch about once a day (no alarm), and I use the alarm at least two or three times a week. I hardly ever use the backlight, the watch hands glow in the dark so it is easy to check the time at a glance in the dark without using the backlight. But even so, it should not cut down the life of the battery as drastically as 9-10 years. According to the manual, 3 light operations (total 4.5 seconds) and daily using the alarm for 10 seconds will cut the life down to 7.5 years. Using the light 5 times a day (about 7.5 seconds) will cut the life down to 5.5 years.

There very well may be a problem with the watch. Others that seem to be in the know have commented that there is a known problem with that model.

I haven't seen anyone point out that there is a known problem with this watch yet. Davidefromitaly pointed out that there were a series of Casio modules that had a high fail rate, but when I specified the module number on my watch he said he had not heard of any problems with that module. But you are right, there very well may be a problem with the watch. And I'm starting to think that may be the case because I would expect the display to have been dim or at least shown signs of dimming upon using the alarm or light if it was the battery. But I can't rule out the battery either since I have not been able to test it under load. And of course there was that one time when the display seemed to dim as a result of pushing a button. So it's hard to say for sure without testing the old battery with something like your ZTS, and not just a regular volt meter.

I guess I will just have to wait and see if the display acts up again with the new battery. I think I will start to shop around a little for a new watch, though. I want a watch I can depend on. The Casio combat watch looks cool, but If I'm going to spend $100+ on a watch I have a few other options in mind. I want an analog face, and preferably some stainless steel :D

 

[davidefromitaly]

Re: CR2025 question

So it's hard to say for sure without testing the old battery with something like your ZTS, and not just a regular volt meter.

I guess I will just have to wait and see if the display acts up again with the new battery. I think I will start to shop around a little for a new watch, though. I want a watch I can depend on. The Casio combat watch looks cool, but If I'm going to spend $100+ on a watch I have a few other options in mind. I want an analog face, and preferably some stainless steel :D

for test watch batteries, simply buy a 1000 ohm resistor and put on the batt for some minutes, if the voltage drop at less than 2.5V is depleted, btw some watches can run also with a voltage of around 0.7V

i can suggest you some citizen eco-drive, they use a li-ion battery that can last also 10 years (Panasonic MT920). this battery never had problem

i like a lot the new casio pro-trek thought solar, they had some problem in the past but now they work very well (Panasonic CTL1616 battery)

for the problem you have observed in your watch, is about the same i have see, the display dim or totally disappear but the battery is charged cause the backlight or the alarm work well. i suppose that the problem is the really cheap construction of the IC, so there can be a batch of watches with this problem. don't know if is solved now

i have some old casio watches (made in japan ok...) and they work perfectly still now after 20 years or so, the batteries last 5-7 years... so this isn't a new technology, the new thing is that casio have moved the production in china and lowered the IC quality, so the fail rate is higher

 

[Stream]

Re: CR2025 question

That's interesting. I may buy some 1000 ohm resistors on ebay and test it on the battery. I'm guessing the way to do it would be to bend each of the ends and tape them to each side of the coin cell battery (+ and -) and then just leaving it there for a few minutes, like you suggested, before breaking out the volt meter to see how far it has dropped. Thanks for the tip :)

 

[Stream]

Re: CR2025 question

i can suggest you some citizen eco-drive, they use a li-ion battery that can last also 10 years (Panasonic MT920). this battery never had problem

i like a lot the new casio pro-trek thought solar, they had some problem in the past but now they work very well (Panasonic CTL1616 battery)

I just googled the Casio Pro-Trek Tough Solar and it looks very cool. All the Citizen watches are very nice looking, but pricey.