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hex4def6 | 5 days ago

As someone who worked on kindle power consumption many years ago: One of the (by far) biggest consumers of power is the WiFi connection. It has to wake up and respond to the AP in order to not get disconnected every x seconds.

Off the top of my head, I think 'on' average power consumption was ~700uA without wifi, and about 1.5mA+/- with Wifi. This is from over a decade ago, so my memory is fuzzy though...

Obviously, page changes used relatively large amounts of power. I don't recall the exact amounts, but it was 100s of mA for seconds.

There is also an "every x pages, do a full screen refresh (black to white)" to fix up the ghosting issue that the article writer saw.

discuss

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thegrey_one|5 days ago

I removed the battery on mine, kept the battery chip and fed 5V into the battery terminals, from Kindle's USB connector, through a diode (so 4.4V-ish). Without a battery it needs something that can deliver at least 1.5A, for short bursts. An older powered usb hub seems to work fine, hub is connected to my raspberry pi, and I use ssh through usb networking, no wifi, no battery, worked fine for months now.

mengchengfeng|5 days ago

Awesome tips. I'll try increasing the refresh interval to 2 minutes and turning off the wifi in between refreshes to see if helps with battery life.

Side note this also finally explains to me why battery life on the Kindle is SO good in airplane mode.

rwyinuse|5 days ago

Yeah you'll probably want to turn on airplane mode between the refreshes. That's at least what KUAL "Online screensaver extension" from Mobiread forums does, with it I'm getting several weeks of battery life with refreshes every couple of hours.

jbl0ndie|5 days ago

Could you adjust the refresh frequency based on your usage patterns? So refreshing less frequently outside your main transit times. An extension of your current pause at night.

ge96|4 days ago

I never connect my RM2 to wifi and it's crazy, I don't charge it for months. Granted I use it maybe under 30 time a month too. I guess WiFi isn't necessarily disabled but yeah.

Haven't modded my paper white kindle, I'm thinking at the very least I'm going to get rid of those forced ads you read when you wake it up.

nanobuilds|5 days ago

wonder if small amorphous silicon photovoltaic cells glued around the kindle would provide enough power to not charge every 5 days