I've never understood the need to have a phone last weeks on a single charge.
For me, usually when I'm having a really long day, it corresponds with using my phone a lot. Like a day stuck in the emergency room for a family member. I'd already had a full day's use of the phone, then spent the next 8 hours having to call family and friends about what was going on. My phone had already gotten normal use that day, so it was at about 30% when I left for the hospital. The brief charge it got on the way took it to about 40%, but with all the calls, texts, etc. by the time we were done the phone had been dead for 3 hours. I've taken to stashing a USB battery charger in the car. It stays plugged in, and can throw a full charge into my phone when needed.
if you're doing it just for your son, maybe. but i know some people still have relatives that aren't constantly at their computer. one of our grandparents turns her computer on once a month to do bills. for her, on dialup, she's not willing to spend time looking at tiny thumbnails to determine which pics to download to look at. instead, we print a pack of 20-30 every once in awhile, and send them to her or bring them with us. she loves them, especially because she can stick them on her fridge, take them to work, etc. and she knows and understand that if she loses them, its not a big deal because we've still got the digital versions at home.
Suggest you just sit there and wait till life gets easier.