Adafruit FONA GSM module, constant charging with USB?

Hi!

I'm building a custom phone for my grandparents using an Arduino Uno and the FONA GSM module.

I want to power the module with a Litium Ion Polymer Battery as backup power, while simultaneously constantly charging via the micro-USB.

According to this this shouldn't be a problem, however since my grandparents are very old i'm rather paranoid. Is it a bad idea to power the device as i decribed? Anyone willing to share some knowledge? Should i look for a GSM module powered normally and not with a battery?

Thanks in advance!

I agree with you that you should take extra precaution with elderly people. Adafruit is never rated for any type of power supply compliance. That is the reason I never make my own lipo battery charger with their charger parts or from sparkfun etc. I've had bloated lipo batteries in my older phones including an iphone. It's dangerous. Sorry this wasn't much of an encouragement to your project. If it is something your grandparents rely on, get them two flip phones. They are easy to use and usually come with options for large fonts. I'm sure they adore your invention even if it is not meant for them 24/7.