How Much Power Does a 3G Modem Draw?

Posted on 23 June 2009, at 1:35 am, by Mitchell Oke

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I received my brand new 13” MacBook Pro about a week ago and for the most part (a few software issues at the moment), I am loving it. One thing I have noticed is that the battery life I’ve been getting hasn’t really been all that close to what others have been reporting online. Anandtech tested the 15” model they have and were able to quite happily achieve close to what Apple said you should be, so why is it I’ve been getting quite a fair bit under 4hrs out of my machine?

Initially I thought it might be because my battery was so new and hadn’t been “broken in” yet. It is now nearing on 10 cycles and life hasn’t really changed.

huaweie220mbp13

That was until last night, when I was using it for the first time on battery at home. I had an indicated 6hrs of battery life remaining, something I had yet to see on this machine. This intrigued me, but initially I couldn’t figure out what it was.

Then it came to me: 3G. Whenever I take my laptop out of the house, it is faithfully accompanied by a USB 3G modem. And almost every time I use my laptop out of the house, it is connected up to provide sweet internets. Unfortunately the coffee shops I visit at the moment do not have free WiFi, so I have to the use the 3G modem if I want to get online.

What has truly astounded me is just how much power the modem is sucking down through that USB port. As I sit here now, I just disconnected my USB modem and watched the remaining time rapidly rise from 2hrs 20mins (at 67 percent) to 3hrs 40mins (at 63 percent). That is simply a huge difference!!

modemdisconnected
USB Modem Not Plugged In

modemconnected
USB Modem Plugged in and Connected

What I’m wondering now is whether it is the particular modem I am using, a Huawei E220 HSDPA modem that came with my data plan. Included in the box is a short, 10cm miniUSB to USB cable, as well as a two-pronged cable (like those that come with 2.5” USB HDDs) should your USB port not be up to the task. I guess this cable should have been rather telling…

I’ll be getting a new USB modem shortly, and it will be interesting to see how it affects the battery life of my MBP13.

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