Battery Issue for Rx3715

[CXImran]

Hi, I'm a former Palm user who recently switched to PPC, one thing I noticed about PPCs is that the battery seems to go from 80% to 8% whenever I go to sleep at night. I power it off using the switch on the top of the PDA and the battery still goes out, is this normal?

[yankeejeep]

A PPC (up until WM5) does not power completely off. The power switch puts it into minimal power usage, so the display is turned off, the CPU is trottled back to its lowest speed, and trickle power flow is provided to RAM to maintain the main memory area. If you have wifi or bluetooth built into your device and turned on, that will also remain powered. And if you have cards in the memory slots, they can also take some power if you have the device set to power the slots even when off. I would suspect with the large power drain that you have a wireless connection option turned on and it is doing its best to find a connection. With your device powered down and no wireless option still active, you should see 10% or less used while it sits overnight.

If you have a email account set to check for mail every xx minutes or have not deactivated the mobile ActiveSync schedule so that it is trying to connect every xx minutes, your device may be turning on and off all night long on the assigned schedule to do the update tasks, and this will also draw your battery down. By default, both of these items are set for automatic, behind-the-scenes connections. You may also have a Today screen plug-in (like a weather app or news reader) that is set to update itself on a periodic basis. Any of these can be peridoically activating your device throughout the night and should have their options checked to see if they are the culprit.

[Menneisyys]

The power switch puts it into minimal power usage, so the display is turned off, the CPU is trottled back to its lowest speed, and trickle power flow is provided to RAM to maintain the main memory area

I wonder if the CPU is needed at all just to give a constant refresh current to the RAM (which is, AFAIK, can very easily be done by just putting, say, a DC level on one of its chip legs.)

[yankeejeep]

I am just assuming that the CPU remains functioning at a low level or items such as alarms and other timed 'wake ups' would not be able to actually run to wake the device up. AFAIK you do need to be running at a minimal level in order for apps to trip the system. I don't know if it even needs to hit double digits, but there are going to be a few cycles per second or apps can't do their little wake-up calls.

[Menneisyys]

I am just assuming that the CPU remains functioning at a low level or items such as alarms and other timed 'wake ups' would not be able to actually run to wake the device up. AFAIK you do need to be running at a minimal level in order for apps to trip the system. I don't know if it even needs to hit double digits, but there are going to be a few cycles per second or apps can't do their little wake-up calls.

Interesting question/remark - I'll look around regarding this question. Dunno if the CPU is needed for this - for example, my Cambrdige (Sinclair) Z88 (an old portable computer; really revolutionary at its time and usable even now for PIM functions & text editing & even simple text browsing on the web) also supports alarm wake-up from hybernation, but has - if you don't use RAM memory extension cartridges; that is, the system only needed to power 32k RAM - about a year (!) or suspension time with normal 4*AA batteries, even with enabled alarms. I don't think 20-year-old technology like the Z88 used the Z80 (which was for sure far less scaalable than current Xscale CPU's) for alarm wakeup functions - really an interesting question worth a detailed investigation.

[yankeejeep]

If I recall the WM5 info correctly, if you turn a device completely off (rather than just hibernate it), the alarms and reminders will not function until it is turned back on. The only thing that continues to function is the system clock; other than that, your device is down for the count until powered on again.