I've been reading some of the threads about battery concerns. I've seen tons of speculation and little deterministic troubleshooting, so I thought I'd put this together:
LTE uses more juice (duh)
"The LTE radio states drain slightly more power than their counterparts in 3G, because the tail states (Short DRX and Long DRX) stay at the higher base power, while much of the 3G tail is in the FACH state which uses half power."
Source: http://developer.att.com/developer/forward.jsp?passedItemId=11900006
"Compared to third-generation (3G) communications, 4G networks will demand more power. Base stations must therefore provide higher power while limiting what they consume (See figure 1). For their part, handsets will struggle against shorter battery life."
Source: http://chipdesignmag.com/lpd/blog/2010/03/11/lte-heightens-power-consumption-concerns/
"LTE MIMO uses two parallel transmissions which is almost analogous to running two phones off of one battery. Limited LTE coverage requirs devices to boost transmission power and dropping in and out of LTE overtaxes battery." (p. 7)
Source: http://tinyurl.com/9596qpl
If you have battery life concerns
It's unlikely (but not impossible) you found a lemon battery pack. There's far too much variability in LTE availability to initially make that leap. If you think you have a problem, start by leaving LTE off for a day or two. Even if battery life isn't what you expect after leaving LTE off, keep it off until you hunt down the issue. Adding the variability of LTE will do nothing to help. Wifi is your friend in this case. LTE power demand is also linked to bandwidth. The faster your particular connection, the more power you draw (see the first ATT link).
Yes, the iPhone 5 has a faster CPU, but that energy demand is deterministic and Apple engineers would have accounted for it. I'd be willing to bet a fine cigar the majority of variability and increased power demand IP5 owners are experiencing comes from LTE.
Battery Myths
I've never seen any conclusive evidence that cycling lithium ion batteries does anything to improve battery life. One of the most respected battery information sources I've ever found on the Internet is Battery University. Their testing of lithium disharge cycles shows 11 packs all demonstrating decreased capacity starting at cycle 0. Keep in mind, these packs were analyzed on professional battery analysis equipment for 250 charge cycles.
Source: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
In the end, we have to recognize we're at the forefront of a relatively young technology in cellular service. Mobile access technology increased at a much faster rate than battery technology. Both industries have work to do in managing power demands with this equipment in the hands of end users. To avoid frustration, it might be best to temper expectations by acknowledging the combination of limits Apple is dealing with in power and the demands of LTE. Some will cite the Razor Maxx. Motorola solved the power issue with brute force: 3300 Mah battery vs. 1440 in IP5. So IMHO that is apples to oranges (no pun intended).
We're carrying 20+ Mbit connections in our pockets. That alone is an amazing feat of engineering. If battery life is critical, slowing the phone's transfer rate down to a mere 1Mbit on 3G isn't all that big of a deal until you can get to a charger. After all, at the end of the day, the fact our phone batteries may not last as long as we'd like because we're rocking multi-megabit speeds truly is a first world problem.
Hope this helps sort out how to adjust to the new realities LTE and IP5 present for us.
J
LTE uses more juice (duh)
"The LTE radio states drain slightly more power than their counterparts in 3G, because the tail states (Short DRX and Long DRX) stay at the higher base power, while much of the 3G tail is in the FACH state which uses half power."
Source: http://developer.att.com/developer/forward.jsp?passedItemId=11900006
"Compared to third-generation (3G) communications, 4G networks will demand more power. Base stations must therefore provide higher power while limiting what they consume (See figure 1). For their part, handsets will struggle against shorter battery life."
Source: http://chipdesignmag.com/lpd/blog/2010/03/11/lte-heightens-power-consumption-concerns/
"LTE MIMO uses two parallel transmissions which is almost analogous to running two phones off of one battery. Limited LTE coverage requirs devices to boost transmission power and dropping in and out of LTE overtaxes battery." (p. 7)
Source: http://tinyurl.com/9596qpl
If you have battery life concerns
It's unlikely (but not impossible) you found a lemon battery pack. There's far too much variability in LTE availability to initially make that leap. If you think you have a problem, start by leaving LTE off for a day or two. Even if battery life isn't what you expect after leaving LTE off, keep it off until you hunt down the issue. Adding the variability of LTE will do nothing to help. Wifi is your friend in this case. LTE power demand is also linked to bandwidth. The faster your particular connection, the more power you draw (see the first ATT link).
Yes, the iPhone 5 has a faster CPU, but that energy demand is deterministic and Apple engineers would have accounted for it. I'd be willing to bet a fine cigar the majority of variability and increased power demand IP5 owners are experiencing comes from LTE.
Battery Myths
I've never seen any conclusive evidence that cycling lithium ion batteries does anything to improve battery life. One of the most respected battery information sources I've ever found on the Internet is Battery University. Their testing of lithium disharge cycles shows 11 packs all demonstrating decreased capacity starting at cycle 0. Keep in mind, these packs were analyzed on professional battery analysis equipment for 250 charge cycles.
Source: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
In the end, we have to recognize we're at the forefront of a relatively young technology in cellular service. Mobile access technology increased at a much faster rate than battery technology. Both industries have work to do in managing power demands with this equipment in the hands of end users. To avoid frustration, it might be best to temper expectations by acknowledging the combination of limits Apple is dealing with in power and the demands of LTE. Some will cite the Razor Maxx. Motorola solved the power issue with brute force: 3300 Mah battery vs. 1440 in IP5. So IMHO that is apples to oranges (no pun intended).
We're carrying 20+ Mbit connections in our pockets. That alone is an amazing feat of engineering. If battery life is critical, slowing the phone's transfer rate down to a mere 1Mbit on 3G isn't all that big of a deal until you can get to a charger. After all, at the end of the day, the fact our phone batteries may not last as long as we'd like because we're rocking multi-megabit speeds truly is a first world problem.
Hope this helps sort out how to adjust to the new realities LTE and IP5 present for us.
J