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New Member

7921/7925 Battery Life & Battery Condition

Hi All,

I recently encountered an issue with battery life on the 7921 and 7925 phones following an update to 1.4(4.3) - the volume of complaitns about shorter battery life from end-users using these phones has gone up quite significantly.

I was wondering if there are any known bugs with this version (so far I have not been able to locate any), and as well if there are any known devices which can used to test the condition of the batteries in these phones. I have contacted Cisco directly, and no such device appears to exist (at least no publically available device). Has anyone successfully used any third party devices or methods for testing the condition of these batteries?

Best Regards,

-Evan

Everyone's tags (6)
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Cisco Employee

7921/7925 Battery Life & Battery Condition

No known issues with recent releases include 1.4.5.3.

However, batteries do not last forever and should be replaced every 2-3 years depending on the # of full cycle charges.

Can also check the date code on the battery (e.g. FS1015.. means mfg in week 15 of 2010).

11 REPLIES
Cisco Employee

7921/7925 Battery Life & Battery Condition

No known issues with recent releases include 1.4.5.3.

However, batteries do not last forever and should be replaced every 2-3 years depending on the # of full cycle charges.

Can also check the date code on the battery (e.g. FS1015.. means mfg in week 15 of 2010).

7921/7925 Battery Life & Battery Condition

Mike,

Thanks for sharing this date code.

__________________________________________________________________________________________
"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
__________________________________________________________________________________________
‎"I'm in a serious relationship with my Wi-Fi. You could say we have a connection."

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________

7921/7925 Battery Life & Battery Condition

What are the remaining numberd in the date code? Does the 7921 read the same way ? Looks different ..

__________________________________________________________________________________________
"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
__________________________________________________________________________________________
‎"I'm in a serious relationship with my Wi-Fi. You could say we have a connection."

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
Cisco Employee

7921/7925 Battery Life & Battery Condition

The rest are just unique identifiers.

For the 7921, it is the same logic.

The first 4 #s are year and week.

For example, I have a standard 7921 battery with date code F07121800649, which is week 12 of 2007.

As you may know, the 7921 started shipping in January 2007.

The 7921 extended battery is the same but has a different prefix.

Date code CM07124928831 is also week 12 of 2007.

7921/7925 Battery Life & Battery Condition

Excellent !  thanks

__________________________________________________________________________________________
"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
__________________________________________________________________________________________
‎"I'm in a serious relationship with my Wi-Fi. You could say we have a connection."

__________________________________________________________________________________________ "Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin ___________________________________________________________
New Member

7921/7925 Battery Life & Battery Condition

Thanks for the prompt responses! Quite helpful being able to discern the manufacturing date to see how old the battery is. Strange that following the update the battery life would be seemingly shorter. Outside of inspecting the manufacturing date, have you encountered any other methods for assessing battery condition?

New Member

7921/7925 Battery Life & Battery Condition

Any idea on the approximate number of cycles that these batteries are expected to last?

Cisco Employee

7921/7925 Battery Life & Battery Condition

The current battery technology allows for around 300-500 full charging cycles (charging from empty to full) before it will lose around 20-30% of its capacity.

So should expect to replace the battery every 2-3 years.

New Member

7921/7925 Battery Life & Battery Condition

Is that for the standard battery? Do you happen to know this information for the extended battery as well?

New Member

Re: 7921/7925 Battery Life & Battery Condition

If I can afford a complement to the question. A battery, such as CM0708 # # # # # # # # entirely new (no charging) will it be as good or needs to be replaced anyway?

     

In addition, I would like to know if it is better to wait until the battery is completely flat to a charging where to place the phone on charge at all times ?

Do leave a phone on charge for extended periods (weeks, months) may damage the battery ?

Ce message a été modifié par: Dany Fortin

Cisco Employee

Re: 7921/7925 Battery Life & Battery Condition

Batteries can degrade / lose capacity over time in storage as well.

Sent from Cisco Technical Support iPad App

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