iPhone battery life vs. Push

Mark Crispin <[email protected]> wrote in
news:[email protected]:

> The WORST battery life setting is

If you gotta instant message, wouldn't SMS be better than email? Email
sucks as an instant messenger.

Doesn't Gizmo have an Iphone app?

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In message <[email protected]> Mark
Crispin <[email protected]> wrote:

>There has been a considerable amount of discussion about setting Push for
>email in the 2.0 operating system for iPhone and iPod Touch, and whether
>that affects battery life.
>
>Here are the facts for IMAP connections.
>
>It is possible that setting Push for IMAP connections will consume the
>battery faster than not setting Push.

Are you using Gmail, or some other server with iPhone specific support
built-in?

The iPhone "mail" app doesn't appear to support the IMAP IDLE
instruction, which is what allows nearly any server and client to
effectively push mail out to any device capable of maintaining a TCP
connection. As a result, the "push" setting is more or less irrelevant
when using IMAP.

>Since Apple has not documented it yet, I will document it for them:
>
>Under ALL circumstances:
> [1] The BEST battery life setting is to have Push turned off, and Fetch
> set to Manually.

This makes sense, unless you have a user who manually checks mail
frequently. A user checking mail manually every 15 minutes will use
more power then the system doing it automatically since the user needs
to turn the screen on.

> [2] The SECOND BEST battery life setting is to have Push turned off, and
> Fetch set to Hourly.

How much mail was being pushed during the test?

On most devices (and note, I haven't investigated the iPhone's battery
life yet), if each mail check event brings in exactly one message, push
vs fetch should consume roughly the same battery life. The more mail
coming in, the faster push will deplete the battery, but it consumes
only slightly more then waiting for a fetch.

However, if on average you receive less mail then your fetch setting,
you're better off with push. Consider a 9-5 office and a user who only
receives internal mail, checking every 'x' minutes from 5pm through 9am
will generally bring in no mail at all, whereas push only requires an
occasional heartbeat.