Coin cell battery dying soon

Hi,

We are facing a critical issue related to coin cell battery. We have our own products,its powering through 3V coin cell battery (BR2450,550mAh). According to our calculation battery should work more than 5 year. But some of the device's battery is dying soon (within 1 month) and all our products are manually potted with our own enclosure.

We are using CC2541 BLE (TI),we found one issue that CC2541's DCOUPL pin always consuming power (1.8v) or is it a problem with potting??? If anyone has any other opinion please share here.

Thanks

Kick said:

Hi,

We are facing a critical issue related to coin cell battery. We have our own products,its powering through 3V coin cell battery (BR2450,550mAh). According to our calculation battery should work more than 5 year. But some of the device's battery is dying soon (within 1 month) and all our products are manually potted with our own enclosure.

We are using CC2541 BLE (TI),we found one issue that CC2541's DCOUPL pin always consuming power (1.8v) or is it a problem with potting??? If anyone has any other opinion please share here.

Thanks

Click to expand...

I would analyze some of the failing units: Even if potted, there should be a possibility to "dig in" where the battery is, and then substitute the battery with a power supply and a current meter. That should give an answer if the battery is self-discharging rapidly due to a production problem or if the electronics is using much more power than stipulated.

Also, you didn't say what kind of potting you are using: I have bad experiences of potting electronics in hard epoxy, as it creates a lot of mechanical stress to the potted electronics. Better to use some kind of slightly flexible compound, which may have still high Shore figure, making it "virtually hard." Such materials may be two component silicons, or some other potting materials. I have not used such stuff for many years and can't remember exact specifications, but suppliers should know what is compatible with electronics.

I am no very familiar with CC2541 but have used other similar TI chips. Often you can find help in TIs forums. For example someone had a related type of problem, and solved it by fixing the design: https://e2e.ti.com/support/wireless_connectivity/bluetooth_low_energy/f/538/t/224394 - the final conclusion in that case being "Do not connect DCOUPL to Vcc..."

I don't know if you have searched in TIs forums, but at least it has been very useful to me.

I have faced a similar problem and the current drawn from the battery was within specs. After some investigation it was discovered that the boards were being shipped to the customers in anti-static bags which were conductive!!! Check your handling of the boards in respect of anti-static precautions and any conductive protection.

Thanks for the reply.

But we are facing this issue in potted boards. Once we potted we can not check the voltage level also, this is the main problem we are facing.