cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
1629
Views
5
Helpful
2
Replies

3802i Question regarding real power draw

derobbacher
Level 1
Level 1

Hello Cisco WLAN experts,

 

we would like to upgrade a great WLAN installation here and ordered more than 1000 3802i-APs.

We looked also into the datasheet of this AP in front of this project to check power consumption requirements

and ended up in planning of ordering also a lot of new Cisco-Switches that can offer POE+ in future.

 

But to my surprise, when I connected the first 3802i to a cheap Cisco SG350 Office Switch,

I noticed, that this WLAN AP is consuming only  11.4 Watt with all antennas up and running perfect.

 

So why is the datasheet stating

25.8W at the PSE (22.5W at the PD) with all features enabled except for the USB 2.0 port

 

30W at the PSE (25.5W at the PD) with the USB 2.0 port enabled

 

To invest into new POE+ Switches would be a million dollar invest for our Hospital.

If the 3802i could be connected and working with elder Cisco Switches offering only PoE

we would save a lot of money instead.

 

So what is the real truth about the power consumption of this WLAN AP model ?

Can it be connected also to old Cisco Switches offering only PoE IEEE802.11af Type 1 max 12.95Watt ?

 

Thank You for Your tips in advance

 

Kind regards

Wini

 

 

2 Replies 2

Rich R
VIP
VIP
You've not supplied any outputs to support your claim that the AP is running all radios at low power but normally it would come up with all radios disabled so that you can configure the AP but it's not operational. Power data for normal full operation:
Interface Admin Oper Power Device Class Max
(Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi1/0/3 auto on 30.0 AIR-AP3802I-E-K9 4 30.0

sh cdp neighbors Gi1/0/3 detail
-------------------------
Device ID: <name>
Entry address(es):
IP address: X.X.X.X
IPv6 address: XXXXX
Platform: cisco AIR-AP3802I-E-K9, Capabilities: Router Trans-Bridge
Interface: GigabitEthernet1/0/3, Port ID (outgoing port): GigabitEthernet0
Holdtime : 179 sec
Version : Cisco AP Software, ap3g3-k9w8 Version: 8.5.151.0
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 2014-2015 by Cisco Systems, Inc.
advertisement version: 2
Duplex: full
Power drawn: 30.000 Watts
Power request id: 50292, Power management id: 4
Power request levels are:30000 15400 0 0 0

As you can see it has 2 power levels - regular POE 15.4W enough to boot, no radios and POE+ 30W for all radios.

Leo Laohoo
Hall of Fame
Hall of Fame
The 3802 will use >30.0w.
At 15.4w (or less), the radios will be disabled.
Something is not right with the switches if the AP is only drawing 11.4w.
Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: