The newest firmware definitely extends the battery life between charges. Its only available in the russian version at the moment but should be out for everyone else soon.
if you would like to try it out, there is more about the new firmware and a download link
https://www.mobileread.com/forums/showthread.php?t=94909
remember not to put the language file on the boox or your menus will be in russian. also with this firmware the browser will default to google.ru. you can just touch the "english" button on the page if you need to search or use the "www" button in the lower right to open the address bar.