iPod Mini 2G battery life is reeeeeally bad (only 25% of stock firmware!)

[eicca]

Normal battery life when running Apple firmware, but when playing fairly low bit rate mono-channel talk show MP3s in RockBox I'm seeing a battery loss as nasty as 20% in ten minutes.

I'm using a 256GB SD card and an iFlash adaptor, brand new battery. I've tweaked all the settings I can think of to reduce disk and screen usage.

Any pointers? Known config combinations to help out?

[saratoga]

I think with the stock hardware your device gets something like 20 hours battery life with normal files.

Maybe the modified storage has some problems? Is the device getting extremely hot while in use?

[eicca]

No temperature problems. This is my second iPod Mini I've tried in an attempt to rectify this issue.

I'm going to run a rough benchmark in stock firmware but even playing lossless in Apple FW lasts noticeably longer than playing cruddy MP3 in RockBox.

[eicca]

Stock firmware benchmark is still in progress, but it's been going for six hours now and is still showing at least 75%-ish battery. Now I know the graphical meter thingy isn't really accurate but last time I benchmarked RockBox it only went about five hours before shutting off.

[eicca]

Apple firmware resulted in 20 hours of playback.

RockBox benchmark is currently in progress, playing the same album on repeat at the same approximate volume as in the Apple firmware test. It's only been an hour and I've already lost 20%. Terrible. Database loads to RAM, doesn't auto-update, all audio enhancements are off. Backlight is off, hold switch is on. Directory Cache is off since I never use the file browser.

What debugging can I do to find out why the drain is so abysmal?

[eicca]

It's getting worse! Just sitting idle I'm watching my battery drop 1% every few minutes, backlight off!

Still no problems in the Apple firmware.

Really need some help, devs!