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Cisco IP Phone 8821 Battery Standby Time

Staempfli_
Beginner
Beginner

Hi all

Since 2 weeks we have 10 8821 Cisco IP Phones in use. On every Phones we have a poor Battery Standby Time. According the Data sheet we should have a Standby Time about 200 hours.

 

The Battery on our Phones is over one night empty.

 

System we run:

 

Cisco Unified CM System version: 10.5.2.12901-1
Cisco IP Phone 8821 Load: sip8821.11-0-3SR4-3
 
Bluetooth is Off
802.11 mode is 5GHz only
On call power save is Enabled
Display sleep is 30 Seconds
Battery Type is CP-Batt-8821
 
Thanks in advance for any suggestions
 
Regards
Andreas 
1 Accepted Solution

Accepted Solutions

I'm not sure but certainly possible. You can go to 8.2.x with 1142 as far as I know before there's a hard limit it's just some features after 8.0 are unsupported. You can definitely go to full-featured 8.0.x with them.

 

Ric

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View solution in original post

10 Replies 10

Ric Beeching
Rising star
Rising star

Have you tried:

 

  1. Extending the DTIM period to 2 instead of 1 on the WLAN so the phone wakes up less frequently to check for data.
  2. Setting scanning mode to Auto instead of Continuous. This is only recommended for deployments where clients don't roam a lot whilst on calls as it reduces background scanning for roaming targets.
  3. If using the phones with a FlexConnect deployment, Cisco also recommend enabling Proxy ARP. I have experienced issues with this feature where printers in particular end up with 169. addresses due to IP conflict and it was caused by Proxy ARP. However, you could always test it and it may work for you.

Ric

 

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Thanks Ric

1. DTIM period on WLC is already set to 2, but the WLAN diagnostic on the 8821 shows a 0. On 7925

   phones is a 2. 

    WLC Software Version is 7.6.130.0. Could that be the reason? I cannot upgrade to 8.x, otherwise

   35 Access Points 1142 will get obsolete.

2. I Will try that

3. Proxy ARP is already enabled

 

Regards

Andreas

I'm not sure but certainly possible. You can go to 8.2.x with 1142 as far as I know before there's a hard limit it's just some features after 8.0 are unsupported. You can definitely go to full-featured 8.0.x with them.

 

Ric

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BRPRoman
Beginner
Beginner

Hi Andreas!

 

We have the same issue since already May. We use ~620 phones in our facility.

 

I see that the problem is solved for you, can you tell me what exactly solved the problem? And how´s about the voice-quality with the on call power save activated?

 

Bluetooth is off

802.11 is 5GHz only

On call power save is DEACTIVATED

Display sleep is 30 Seconds
Battery Type is CP-Batt-8821
CUCM is 11.5.1.12900-21
8821 phone load is rootfs8821.11-0-3SR4-3
 
As soon as we activate the "on call power save", the quality of the calls is going down and is not usable anymore. Calls are interrupted, have lags, they´re chopped and sometimes there are breaks for 2-3 seconds so you can´t follow the communication anymore. So at the moment it is not an option for us to activate it.
 
Would be nice to know what fixed the problem for the battery issue on your side and how long you can have them in standby now.
 
many thanks in advance for your feedback,
Roman

Hi Roman

 

Honestly I maybe was a little to early with my statement that the problem is solved, I'm sorry for that.

On the Wireless Controller we run the Software Version 7.6.130.0.

 

Recommended is 8.0.140.0, 8.2.151.0 or 8.3.112.0

 

In the next few weeks we plan an upgrade on the WLC to Version 8.3.112.0 and I hope this will solve the problem.

 

 

Regards

Andreas

Hi Andreas

 

Did you resolve the problem by upgrading the WLC ?Thanks

 

Regards

Jasper

gordthom
Cisco Employee
Cisco Employee

Hello Andreas,

 

Please let us know if you resolved the issue.  If not here are a couple of things that might be affecting the battery life.

 

1.  Defect CSCvf59659  deals with phone logging that keeps the phone in an active mode so it never goes to standby mode which can drain the battery.  This will be fixed in firmware SR6 which should be out in the next week.

 

2. Check to see if the 8821 phone ever goes into sleep mode.  If it does not change the sleep to another time setting first then check if it goes into that sleep mode at that time. the sleep setting is under the phone display settings on the phone.  I have seen an issue where some new 8821 phones don't do to sleep until that setting is changed at least once. 

 

Thanks

Gordon

 

 

Hi Gordon
For the SR6 how many bugs that will be fixed on this version of firmware? We are hitting a few of them at the moment. Thanks
Regards
Jasper

The following defect fixes are resolved starting in SR6.

CSCvg46824

CSCvg40435

CSCvg66059

CSCvg69345

CSCvg64790

CSCvg45158

CSCvg74852

CSCvg68954

CSCvg61117

Thanks Gordon.

 

Cheers

Jasper

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