Cowon AW1 battery problems

prakashks

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Hi all,
I had purchased the Cowon AW1 from Japan BIC Camera last year. After a year i started to observe that the dashcam used to become hot. Soon after that i started to see that the camera would stop recording once the vehicle stops. What i mean is once the vehicle is stopped and started next day or few minutes later the dashcam just keeps blinking red and stops and nothing happens after that. What i observed is that if I format the sd card then it would record that drive till vehicle is running.

Again once vehicle is stopped next start same problem . So what i believe is that the internal lipo/li-ion battery might have conked off which results in abnormal termination of recording on SD card when the vehicle is powered off .

So i disassembled the unit as shown in the posts here, but i am thinking would it be possible to have a capacitor instead of this battery. Any suggestion for battery replacement as i don't have any service center here in India :-( .. Any help / suggestion would be very helpful..

Regards
Prakash
 
I will be in Japan, so with help of my Japanese colleagues found a place in Akhiabhara area who sells some thing which is similar. Will buy and let know my experience. The web link for the same is below http://www.aitendo.com/product/9667

Regards
Prakash
 
So finally i made to the shop and bought 3 units of the battery as reserve, costed me 450Yen+Tax for each. Also assembled the battery into the unit and there is ample space left still for battery. I will power on the unit once i go back to India next week and update my experience. Hope some one who has this problem will get benefited by this..

IMG_Shop.jpg Shop front view

IMG_batteryCompare.jpg Battery Size comparison

IMG_NewBttryIn1.jpg IMG_NewBttryIn2.jpg After replacing the battery in unit , perfect fit..

Keeping fingers crossed (y)

Regards
Prakash
 
I am writing with heavy heart that even after i replaced the unit with new battery... the symptoms remain same. So even now after formatting the card the first recording goes fine. With Car power off, the unit does not come up with next power on. So i even replaced the sd card with a class10 Sandisk 16GB one so that faster writes are supported.. but even that seems not solving...

Really i appreciate if some one can give some lead / solution to this kind of behavior. I am not sure how much COWON support is helpful in this regard... But i am sure some one in forum will throw some light .. :nailbiting:

Regards
Prakash
 
What was the other card you were using? SanDisk Ultra cards shouldn't be used in dash camera. You could get results like you experienced.
 
Thanks for your reply.. But any reason for not using Sandisk Ultra Mirco SD card in DashCams? As i see this SD card has support for faster write and operates at more wider temperature ranges too..

My earlier card came along with COWON AW1 unit and has no branding as such on the card :) ... And even with that card i am experiencing the same problem..

Regards
Prakash
 
:eek: wish i had read this article before my purchase.. But as of now i am living with the glitch with a self made work around..ie.. daily when i start the dashcam, i eject the sd card and reinsert when the dashcam says no sd card found.. It then shouts to format it couple of times.. and then stops and starts recording the drive..:p:D ... Let me see how long this goes on....
 
I see that the battery marked in the attached picture has gone bad.. It has some green color corrosion on it. So does any one know what is the rating of this button cell and is it rechargeable one.
Capture.PNG
 
I think as long as you have the voltage and size of the battery you should be able to find something useful.
The MAH rating i dont think matter much on these little suckers.
 
Thank you for your replies.
I find myself lazy sometimes and decided to delve into this power-supply board and find out what it is.
Unfortunately, the manufacturer offers no clue as to what this tiny battery is as it has no markings and once the battery has died, it's impossible to measure it directly.
In an attempt to offer something back to this community, here's what I've found.

The + side of the battery is charged from output 6 of an Active 8810QJ power management chip. Output 6 is designated for the RTC circuit (real time clock). This is a programmable output voltage which I've determined to be 3.36v.
This output is modulated to a maximum output of 30mAh.
Essentially, this small battery is a manganese lithium 3v rechargeable battery. The RTC used on this camera is a Maxim DS1337+ and has a current requirement of between 200 and 500nAh. This mean that a 5mAh battery will maintain the RTC in backup mode for approximately 1 year without being powered on. The spacing on the PCB pads is exactly 1.5mm.
@kamkar is 100% correct in saying the MAH rating doesn't matter, however, so long as the maximum charging rate doesn't exceed 0.12C for the battery.

Here is a perfect high quality replacement for the generic battery.
https://www.digikey.com/en/products/detail/panasonic-bsg/ML-621S-DN/278835 <------ if the link doesn't work, search for a Panasonic ML621S/DN. ML621S/F9D to be exact with the tabs.

This battery is 3v, 5mAh, 6.8mm wide and has a tab spacing of 1.5mm and fits perfectly.

The above fix will put it back to factory specs if you're happy to occasionally replace the battery as Cowon has made an engineering mistake on this board that will definitely reduce its life span.


Error #1 - They are charging the tiny battery at 6C which is 50X the .12C standard charging rate suggested for manganese lithium cell batteries. 30mAh is WAY too high and should be in the 600uAh range.
Error #2 - Manganese lithium cells should never be charged above 3.1v and they are 0.25v higher at 3.36v.

Either of these conditions are detrimental to the life of the battery and together perfectly explains why they are releasing the green goo after a year or two.. Possibly sooner if the battery is allowed to get too low.
I will be modifying my board with a series resistor and a voltage dividing circuit to exactly 3.1v and .6mAh as suggested by the manufacturer. This will provide me years of trouble-free service.
If anyone is interested I'll gladly post the upgrades here, but I doubt there's much interest in such an old design.

Cheers!!
 
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