I've been carrying out a few tests over the last month and believe I've come up with the definitive guide to improving battery power on a debranded WM5 i600. All tests were carried out on the same moby in near identical environments with a fully charged standard battery, the same setup, profiles, test usage (sms, calls), nothing running in the background and using the same base station so signal strength was consistant.

Most of these will be familiar to i600 owners but I thought it might be interesting to share my findings. Please do feel free to comment if you have any further tips. Here goes:

1. Switch off 3G if you don't need it
   This is the single most effective tweak to improve battery life. To do this, type *#1546792*# and then choose Network & Call Settings - Network Mode from the admin settings window. Select GSM to turn off the 3G module.
   
   
2. Reboot i600 after charge
   This is a strange one. After charging your phone fully via the adaptor, switch off the handset and then disconnect it from the adaptor before switching it back on. I tried this several times and battery life was improved considerably from 1 day to 3 days. I have a feeling it might be linked to ActiveSync (see below).
   
   
3. Reboot i600 after ActiveSync
   After syncing via ActiveSync 4.1, the battery life of the i600 worsens. Rebooting the moby after disconnecting from ActiveSync makes a world of difference. Maybe it's to do with the charge through USB or maybe it's just ActiveSync, in any case, my test handset jumped from 1 to 3 days before expiring by rebooting after using ActiveSync.
   
   
4. Reduce backlight time and intensity
   Go to Start - Settings - More - Power Management and change the Backlight time out on battery to 10 seconds, Display time out to no more than 30 seconds and Display brightness to level 1. I also changed the Keypad backlight on setting to custom so that it only comes on between 8pm and 8am. The display eats up battery power and setting this to level 1 and reducing the time it's on brings good improvements.
   
   
5. Disable beams
   Go to Start - Settings - More - Connections - Beam and deselect the Receive incoming beams option. Small improvement overall.
   
   
6. Disable Bluetooth
   Go to Start - Settings - More - Connections - Bluetooth and deselect the Turn on bluetooth and Make this device visible to other devices options. Modest improvment overall.
   
   
7. Switch off Wi-Fi and reduce timeout
   Go to Start - Settings - More - Wireless Manager and switch off Wi-Fi. No point having it on all the time unless you're really using it. Next, press the menu right soft key in the Wireless Manager screen and select Wi-fi Settings to show a list of all your Wi-Fi networks. In there, press the menu right soft key again and choose Wi-fi Settings again to show the Wi-Fi Networks screen. In here, change the Turn off Wi-fi if not connected in to 5 minutes or less. This ensures the Wi-Fi will stop if there's no activity after the period of time you specify.
   
   
8. Switch off GPRS
   If you use GPRS, switch it off when no longer needed by going to the Wireless Manager and stopping via the Phone option. The default behaviour is for GPRS to stay on for a while and then switch off after a period of inactivity.
   
   
9. Use Opera Mini
   For browsing, Opera Mini is much quicker than PIE and even Opera Mobile as it compress the web page at the server end before sending to your handset. This means less work to do for the i600 CPU and hence it helps stretch the last few miserly electrolytes from the battery. See my post here for which MIDlet managers work best with Opera Mini on the i600.
   
   
10. Tone down the tones
    Set the sound for any system events to a standard beep or short tone rather than an extravagant MP3 clip from your favourite song. Switch off any sounds such as camera (Start - Camera - Menu - Options - Camera and/or Camcorder) or keypad tones (Start - Settings - Sounds - Other Sounds - Keypad control). Tiny gains in extending battery power but more importantly, it keeps the rest of us sane to not hear a tinny Coldplay number from 30 somethings trying to act cool on the train.
    
    
11. Use boring homescreens
    Avoid elaborate homescreens that use lots of plugins. Each of these plugins draws a tiny bit of power from the battery and not all plugins work well with the i600, Smart Monitor in particular seemed to kill my handset stone dead. Stick with the standard available plugins where possible.
    
    
12. Clear the Task Manager
    Shut down any process running in the background that you don't need. Games in particular are a big battery drainer. Hold down the home key to launch the Task Manager and stop anything you don't need. ActiveSync has a mind of its own and will happily launch several times during the day, it didn't have any effect on battery life for me so you can leave that running (but see point 3 above).
    
    
13. Switch off telephony
    If you're on the plane or Tube or anywhere else where reception is patchy or unavailable and you can't or don't need to make calls, switch off the telephony module via the Wireless Manager. With the telephony switched off, I've done a 30 hour round flight using the i600 as an MP3 player (WMP) that even included 3 full episodes of the Simpsons via Core Player. And all on a single charge!
    
    
14. Use extended battery
    Most obvious of all, use the extended battery instead of the standard one

Now here's a novel way to improve the battery life of your i600 (sort of!). The battery meter of the Samsung tends to be fairly accurate most of the time but I've noticed that occasionally, and particularly after an ActiveStink 4 session (thanks Microsoft for yet another piece of over-engineered bloatware), the battery meter tends to report the battery is running down like it's powering a Kenwood Chef.

For example, I usually get 4 days usage from my i600 but after syncing or travelling abroad and returning to Blighty, my moby is usually dead within 2 days. A reboot can help with this as per the tips in the first post but I've found a far more reliable way of resetting or calibrating the battery levels as reported by WM5.

I simply fire up a game of Virtual Pool and have a quick play on that! Once I exit the game to the home screen, I'm back up to 4 days of usage with the battery meter once more reporting the remaining power accurately. I've tried this several times, the first quite by chance, and it's worked on every occasion. I've no idea why it helps with the battery power and can only hazard a guess that a demanding app such as Virtual Pool might shut down anything running in the background that's not shown in task manager to free up resources.

Next test is to find out if this works with all games and CorePlayer or just Virtual Pool