The Push vs. Fetch Battery Debate

[macDonalds]

So at first I heard one of the main advantages of push email was that it was less of a burden on your battery life. Then all of a sudden, posts started to crop up denying this. Some people apparently turning off push in favor for fetching.

Now I only know what happens on the surface with push vs. fetch and it seems logical that PUSH would be the better choice in terms of preserving battery life.

Last night was the first time that I went strictly push (since MobileMe was actually working for ME *knocks on wood*). This morning when I awoke, I was pleasantly surprised at my remaining battery life. It was most definitely better for push than when it was fetch.

What are your experiences?

 

[Apple Ink]

It has to be push! lol
Since its the server which 'pushes' the mail and the client (iPhone) doesn't have to struggle to retrieve the mail......

 

[OasisNYK]

I have to say - getting exchange e-mail on this device is pretty awesome!

I am using push for now but I dont really have anything to compare battery life to since I didnt have iphone 1.0 and just upgraded from a Razr (which had awful battery life).

 

[vandozza]

but in order to recieve a push doesn't the iPhone have to keep a constant connection to the server alive. like a heartbeat for activesync?

i would love to know the answer to this question... i'm sure someone will do semi-scientific tests soon, that will tell us the answer!

 

[OasisNYK]

Good question - I was thinking it would only update when new mail comes in and gets pushed to the phone - but how would the phone know to accept the connection unless it was open all the time?

Experts?

 

[macDonalds]

Good question - I was thinking it would only update when new mail comes in and gets pushed to the phone - but how would the phone know to accept the connection unless it was open all the time?

Experts?

Right, I thought about that as well.

Could have been a coincidence, but like I said - my first over night with push, did not drain my battery nearly as much as my 15 min fetch schedule.

 

[bdorpetzl]

Good question - I was thinking it would only update when new mail comes in and gets pushed to the phone - but how would the phone know to accept the connection unless it was open all the time?

Experts?

Speaking in terms of Exchange, the phone knows to accept the connection because of the active sync partnership established when you first set your phone up with the email account.

I have not noticed any battery difference on my 1gen iPhone bewtween push of fetch. Seems the same. I'll see how it goes when I get my 3g iPhone today.

 

[ElecEagle]

Obviously, fetch opens a connection to the server at specific intervals, whether you have anything to fetch or not ...push only opens a connection when the server tells it there is something available.

Although I'm not 100% sure, there shouldn't be a continuous connection needed. The server should simply send a small data packet to the phone when it has something to deliver ...which should then trigger the phone to go 'fetch' it. This would make sense as 'fetch' and 'push' would use the same code on the phone, it's just that the 'trigger' event that is different.

 

[bdorpetzl]

Obviously, fetch opens a connection to the server at specific intervals, whether you have anything to fetch or not ...push only opens a connection when the server tells it there is something available.

Although I'm not 100% sure, there shouldn't be a continuous connection needed. The server should simply send a small data packet to the phone when it has something to deliver ...which should then trigger the phone to go 'fetch' it. This would make sense as 'fetch' and 'push' would use the same code on the phone, it's just that the 'trigger' event that is different.

This is the way I have understood push, small data packets, sort of like text messages, sent between the phone and server. So I agree with your explanation 100%.

 

[WirelessMan]

Push is better due to the fact the phone itself is not doing the work. The server is. Hence is why blackberry's have an extreme good battery life.

 

[vandozza]

i'm not disagreeing with anyone in particular, but i think that the "active" part in activesync will be a continual connection of some kind between server-device.

i agree that the server sends a small bit of data to tell the device to download mail etc, but to send that small bit of data, doesn't there still need to be a constant connection?

im going to go google this

 

[ljones]

I'm thinking the phone is using battery life, because i had this issue unaware that push was on, yet I have nothing pushing and my email is set to manual.

So there is definitely something going on, my battery never died overnight, and that still seems excessive even if i had push on.

 

[vandozza]

this page http://msexchangeteam.com/archive/2004/04/26/120520.aspx suggests that exchange works via smtp/sms.

ie. a sms is sent to your phone, the exchange part of the phone is monitoring the inbox. upon receipt of this sms data, the exchange is triggered.

so the benefit of push email seems to be instead of requiring -
- 1 constant sms connection + fetch data every x min

you get to rely on the -
-1 constant sms connection + fetch when required

it seems the exchange "pushes" and your sms data share the same constant connection. overall requiring less "connections"

if anyone knows better than this, please feel free to correct this!

 

[bdorpetzl]

Push is better due to the fact the phone itself is not doing the work. The server is. Hence is why blackberry's have an extreme good battery life.

Most of what happens with the Blackberry takes place between the Blackberry Server and Exchange server. The BB server constantly scans user mailboxes on the exchange server for changes. When changes are found, it pushes to the phone. The BB server also pings the phone roughly every minute.

Managing BBs really doesn't make me like them too much. Pain in my ______.

 

[GNice]

Push is better due to the fact the phone itself is not doing the work. The server is. Hence is why blackberry's have an extreme good battery life.

The battery in my latest Blackberry Pearl (this is my second), isn't any better than my iPhone 3G. My first Pearl was better than both. Just another data point.

It appears to me battery life varies even amongst the same type of device.

 

[semi5]

this page http://msexchangeteam.com/archive/2004/04/26/120520.aspx suggests that exchange works via smtp/sms.

ie. a sms is sent to your phone, the exchange part of the phone is monitoring the inbox. upon receipt of this sms data, the exchange is triggered.

This artcle is very old and does not describe at all how push email currently works.

1. A connection is made between the device and server.
2. This connection is kept open between the two, but this does not mean that data is being transmitted
3. If new email comes into the server, the server will notify the device that it needs to sync.
4. If no new email comes in, the device will re-establish the connection (by default, every 15 minutes).
5. During that 15 minute interval, if no new email comes into the server, nothing is being transmitted between the device and server.

 

[kdarling]

but in order to recieve a push doesn't the iPhone have to keep a constant connection to the server alive. like a heartbeat for activesync?

Yes, it does. For instance, a machine somewhere along the path could easily have a small IP timeout and close connections. Or the carrier system could drop your IP address.

So depending on your situation, a heartbeat data exchange could take place anywhere from every five minutes to every thirty minutes (more often the latter).

this page http://msexchangeteam.com/archive/2004/04/26/120520.aspx suggests that exchange works via smtp/sms.

That's the way Exchange used to work. It was superior in that SMS (being a form of an incoming ring) is as close to a real Push as possible, and doesn't require an IP based heartbeat. (Also, a phone keeps a static phone number, but its IP address changes fairly often.)

The downside at the time was that SMS didn't use to be that fast or solid a delivery, and of course it costs per message.

 

[iNfowarrior]

Can I just say?

Who cares?

Push is a great new feature. Use it. Stop being that guy who turns off push, 3g and every other great feature so he can have 50 hrs of talk time to with his cat.

 

[ScottFitz]

I've tried both ways and I'm thinking now that push uses less battery. My biggest battery savings came from disabling the GPS. I"m now running 3G all the time, 50% screen brightness and push emails (which I get a decent amount of) and my battery life has gone up dramatically.

 

[RooDBwoY]

this page http://msexchangeteam.com/archive/2004/04/26/120520.aspx suggests that exchange works via smtp/sms.

ie. a sms is sent to your phone, the exchange part of the phone is monitoring the inbox. upon receipt of this sms data, the exchange is triggered.

that used to be the case but not since SP2 of Exchange Server 2003.

now the following is the case:

"The versions of EAS supported in Exchange Server 2003 Service Pack 2 and Exchange 2007 use a significantly different technology called Direct Push (Figure 1). Direct Push, which is supported by Windows Mobile 5 with MSFP (or later) and a number of EAS licensees, uses a client-created HTTPS connection to the server. The mobile device creates a connection and keeps it open for a duration known as the heartbeat interval, sending an initial synchronization request when the connection is opened. The server will then take several actions:
• When the device makes an initial connection, it may send the heartbeat interval and a list of subscribed folders to the server. If the server receives these items, it stores them in an XML file in the user’s mailbox; if it doesn’t receive them, it retrieves them from the mailbox.
• The server will ask the mailbox server for notification of changes to items in the list of subscribed folders from the device.
• If there are unsynchronized changes on the server, the server immediately returns a status code that tells the client that changes are available; the client will then initiate synchronization and pull the new changes.
• If there are no changes since the last synchronization, the server does nothing.
• When the heartbeat interval expires, the server sends a notification to the client, which can then re-establish the connection."

 

[SPeditor]

I've tried both ways and I'm thinking now that push uses less battery. My biggest battery savings came from disabling the GPS. I"m now running 3G all the time, 50% screen brightness and push emails (which I get a decent amount of) and my battery life has gone up dramatically.

How do you disable the GPS? And what features will I lose when this is off?

 

[markgamber]

I've tried both ways and I'm thinking now that push uses less battery. My biggest battery savings came from disabling the GPS. I"m now running 3G all the time, 50% screen brightness and push emails (which I get a decent amount of) and my battery life has gone up dramatically.

If timely email is critical, push is the way to go and it sucks down less battery than relatively rapid polling of a server. If it's not all that important, polling hourly or manually is the way to do. My wife, for example, checks her email like twice a day on the laptop. Push makes no sense for her and so I have hers set up to check hourly. For me, push is the only way to go because of work mail. As far as battery life with push enabled, I see no difference between the iPhone and my Windows Mobile phone. If you get a LOT of mail, folders and rules may help. For example, if you get lots and lots of mail, some of which you don't care about, create folders and a rule to move mail from the main inbox, which gets pushed, to a folder which does not get pushed. Why get it pushed if you don't care about it?

On battery life in general, I have my screen brightness down somewhat, GPS turned off, bluetooth turned off, Wifi turned off unless I need it and 3G turned off unless I need it. GPS should be off for everyone. The only thing that uses it right now is Google Maps and that's worthless junk. Bluetooth is totally useless unless you have a mono headset for phone calls. If you don't use it, turn it off. My battery life has increased tremendously since doing all that. Some people complain that "I'm not turning off the reasons I bought this phone" but in that case, your complaints are meaningless. What do you think is going to happen? If you're stubborn about it the battery fairy will wave her wand and suddenly your battery life is tripled? That Apple is sitting on a nuclear fusion battery just to mess with you? No, for the foreseeable future you can't have it both ways. Either turn off the stuff you don't need or don't use or suffer a battery that goes a few hours between charges.

All that having been said, the time between charges when I pulled the phone out of the box didn't really seem any worse than any other smartphone I've ever used, and I've used plenty over the years. Sure, it's a LOT worse than a cheapie Nokia, but compared to a Blackberry 8800 or a Sprint Touch, it's more or less the same.

 

[markgamber]

How do you disable the GPS? And what features will I lose when this is off?

Settings->General->Location Services (set it to OFF)

What will you lose? Nothing worth mentioning.

 

[TheKingDingus]

Push vs Fetch with GMail ??

The information everyone has given is very helpful (thank you). But what if the device is NOT connecting to an Exchange server? Will the push mechanisms still work as described above for GMail or any other SMTP/Pop account? What if the account utilizes IMAP?

For the record, I currently have multiple email accounts configured on my iPhone and they are either SMTP/POP or IMAP accounts. I configure them for 15 minute "fetch" cycles mostly because I don't know if a "push" would work for those accts since they are not Exchange based.

I also thought it might have something to do with the emails' final resting place; I thought "push" caused the message to be stored on the device and off the originating email server. Anybody care to help explain this one to me as well?

Thanks for any insight