Observation on Battery Life

[BigRedGonzo]

First of all, at work my reception has always been bad (1 to 2 bars) and since the update it drops all the way to 1X sometimes. My company has recently installed a Wireless Network for vendors to have access to the internet. I decided that since network speed is always (at least in my case) faster over WiFi that I would set up a profile on my phone to hook into the Visitor network at the office instead of using Verizon. Prior to the network install, I would take the Droid off the charger at home at 6:00 am and when I would leave work at around 4:30 pm my battery would be at around 30-40%. Now that I have access to WiFi at the office, I never leave with less than 80% and sometimes its still at 90%. I do not charge my phone at the office unless I decide to listen to Pandora and I very seldom do that. I also hook into the WiFi at the house instead of using Verizon's network and now instead of 10-20% battery at 11:00 pm when I usually plug the phone in I am usually on 70%. I use the phone at work quite a bit for e-mail, phone calls and some office applications, so I would consider it moderate usage during the day.

Anyway, I just thought someone may find this interesting or useful.

BigRedGonzo

 

[jmt9779]

Makes sense. When the phone is searching for a stronger signal it'll really spank your battery, but (I assume, since I never use wifi on my phone) when you hook it onto a pretty strong wifi signal, it doesn't waste power searching for something better from Verizon's network.

 

[BigRedGonzo]

I heard this from the dude at the Verizon store. I like him and he seems very knowledgeable and on occasion I have heard him respond with, "I don't know." In my mind, that gives what he says a modicum of value. Anyway, he told me that for every bar you drop the battery uses about twice the power to use the signal that it is left with and that the worst situation that you can get into is the case where the signal bobbles back and forth between 1X and 3G. He says that if you can hold the 1X the battery will do pretty well and if you can hold 3G it will also do pretty well, but the constant switching between the two is a battery killer. Here recently I have had a lot of bobbling between the two states in the office. I guess my biggest question is what happened with the update to cause the signal issue? I was under the impression that the new radio delivered with the update was supposed to be better.

BigRedGonzo

 

[jmt9779]

I heard this from the dude at the Verizon store. I like him and he seems very knowledgeable and on occasion I have heard him respond with, "I don't know." In my mind, that gives what he says a modicum of value. Anyway, he told me that for every bar you drop the battery uses about twice the power to use the signal that it is left with and that the worst situation that you can get into is the case where the signal bobbles back and forth between 1X and 3G. He says that if you can hold the 1X the battery will do pretty well and if you can hold 3G it will also do pretty well, but the constant switching between the two is a battery killer. Here recently I have had a lot of bobbling between the two states in the office. I guess my biggest question is what happened with the update to cause the signal issue? I was under the impression that the new radio delivered with the update was supposed to be better.

BigRedGonzo

Well, the whole "using twice as much battery power for each bar of signal you lose" doesn't make much sense. That would break down like this: If I have 4 bars and my battery lasts 24 hours, then 3 bars would give me 12 hours, 2 bars would give me 6 hours, and 1 bar would give me 3 hours and you can see that you end up with an exponential decline in battery life. I couldn't tell exactly how the radios appropriate battery power, but I can tell you that it doesn't work like that rep's explanation.

I also wanted to mention this thread:

http://androidforums.com/motorola-droid/61567-declining-reception.html

We don't seem to have an answer yet, but it's clearly a widespread thing - You're not alone.

 

[BigRedGonzo]

Well, the whole "using twice as much battery power for each bar of signal you lose" doesn't make much sense. That would break down like this: If I have 4 bars and my battery lasts 24 hours, then 3 bars would give me 12 hours, 2 bars would give me 6 hours, and 1 bar would give me 3 hours and you can see that you end up with an exponential decline in battery life. I couldn't tell exactly how the radios appropriate battery power, but I can tell you that it doesn't work like that rep's explanation.

I also wanted to mention this thread:

http://androidforums.com/motorola-droid/61567-declining-reception.html

We don't seem to have an answer yet, but it's clearly a widespread thing - You're not alone.

Point taken and understood, but the only problem with that reasoning is that only a very small portion of the battery is used for signal reception (phone idle,) when the phone has good reception, not all of it. Based on my recent observations, I have more information to argue the Verizon Dude's point than the other way. Of course, my observations are only that, observations. I have no way to quantify what I am seeing from a batter life standpoint.

BTW ... Thanks for the link, I've been following that one also. It seems to me that it must be the update because I can't imagine the the entire Verizon network taking a dive at one time.

BigRedGonzo

 

[Lock-N-Load]

seems wifi would increase battery use

not only are you searching for a signal normally, but now your asking the phone to ALSO search for a wifi... thats a lot of outgoing pings

 

[Lock-N-Load]

seems wifi would increase battery use

not only are you searching for a signal normally, but now your asking the phone to ALSO search for a wifi... thats a lot of outgoing pings

 

[BigRedGonzo]

seems wifi would increase battery use

not only are you searching for a signal normally, but now your asking the phone to ALSO search for a wifi... thats a lot of outgoing pings

From what I understand the Droid (or I guess maybe Android system) chooses networks preferentially. So if it has WiFi access, it drops the radio back to 1X only and turns off 3G. I don't have any documentation to support this, but I read it on a forum somewhere and it seems to hold true with my phone.

 

[takeshi]

I'm not sure it shuts off 3G but if WiFi is available it will use WiFi for data. For the same amount of data, WiFi should consume less power. That's what Lock-N-Load is missing from his equation.

 

[Lock-N-Load]

BUT

it must be searching - which is power and effort - to find a WiFi. It can't find "if WiFi is available" unless it spends effort and power going out and pining and looking for networks. it finds them by taking power looking for them.

"For the same amount of data, WiFi should consume less power." - I won;t argue that as I have no idea. BUT the question I posed, not answered, is that to FIND that wifi is going to take more battery power. So sure, when it is locked on it might be more of a battery saver. It is finding, maintaining, pinging for a better channel that seems it would take more power in the end.

So, if I was at work and locked into a great wifi channel that is fine, but then as I drive home it takes power and effort going out and looking for any wifi channel. And it might also search for a better and stronger "preferentially" chosen network. So, when I get home, it lists my 5 neighbors as well as my "preferred" home wifi channel. It still shows the other 5 and not just mine.. seems to me, constantly keeping tabs on all the wifi going on around you is taking battery and power even IF you are locked into your preferred wifi network.

 

[BigRedGonzo]

BUT

it must be searching - which is power and effort - to find a WiFi. It can't find "if WiFi is available" unless it spends effort and power going out and pining and looking for networks. it finds them by taking power looking for them.

"For the same amount of data, WiFi should consume less power." - I won;t argue that as I have no idea. BUT the question I posed, not answered, is that to FIND that wifi is going to take more battery power. So sure, when it is locked on it might be more of a battery saver. It is finding, maintaining, pinging for a better channel that seems it would take more power in the end.

So, if I was at work and locked into a great wifi channel that is fine, but then as I drive home it takes power and effort going out and looking for any wifi channel. And it might also search for a better and stronger "preferentially" chosen network. So, when I get home, it lists my 5 neighbors as well as my "preferred" home wifi channel. It still shows the other 5 and not just mine.. seems to me, constantly keeping tabs on all the wifi going on around you is taking battery and power even IF you are locked into your preferred wifi network.

I don't disagree at all and now I see that I should have mentioned that I have a package installed that turns on WiFi when I want it on. When at home and when at work, the WiFi comes on automatically and hooks up to the "Remembered" network in that area. I didn't mean to sound as if I had all the answers, it was just an observation that I had made.

Here is another bit of data to add to the pile. Every day that I have been at work and used the network connection at the office, I get the best battery life that I ever had. This weekend, I attended baseball games all day on Saturday and, of course was outside. I had a 4 bar 3G signal the entire day. When I went to bed that evening, I checked my battery level. I had definitely not used the phone like I would have had I been at work and my battery level at bedtime was shown as 30%. I unplugged the phone at around 6:00 am (like normal) and hit the road. We went several places, but the majority of the day was spent at the ball field with good reception. In my mind, this points pretty hard at WiFi taking less battery than 3G. Of course, I guess if you were in a situation where WiFi dipped in and out like 3G does quite often, it wouldn't help any.

 

[inssane]

seems wifi would increase battery use

not only are you searching for a signal normally, but now your asking the phone to ALSO search for a wifi... thats a lot of outgoing pings

I concur