Hi luhu,
all your questions are already answered in the github link 
as far as I know you’ll need at least a Kindle 2 (using Advanced mode browser).
for me on a kindle paperwhite with 0 light the battery lasts for about 2-3 weeks on each charge, but i bought a slim microusb connector so I can put it on the wall have it plugged in
and you can disable the screensaver like this:
Newer kindles (2015 Paperwhite & up) type ~ds in the search bar and click search. (Don't worry, After restarting the Kindle the screensaver will return)
Older Kindles: Type ~disableScreensaver in the search box (type del on the home screen) and your Kindle will not go into sleep mode. ~resumeScreensaver will revert the Kindle back to its default (screensaver enabled) state. Note that this does not increase power consumption, as the Kindle consumes no power (with wireless off) when displaying a page
Or < Del > to open the search box on the home screen ;debugOn ~disableScreensaver NOTE: this also stops you from manually using the power switch to enter sleep mode. To re-enable: ~resumeScreensaver and to turn off debug mode: ;debugOff
@gurbina93 - if lovelace works on kindle its probably better than this, but I dont think it does