Wow seven hours yeah that should be enough depends on their hold strength left. But they only last for how long? haha
In the not to distant future, mobile phones and stuff will charge instantly using graphene batteries and will last for months at a time instead of days. Airplanes will be much stronger and be able to fly for months without charging and when it does it will be instant.
You can find out about graphene and what it is online. Basically, graphene, is a nano thin layer of pure carbon atoms that are bonded together in a hexagonal honeycomb shape on a nano scale. It is about 100 times stronger than steel by weight, conducts heat and electricity with great efficiency and is nearly transparent.
[video=youtube;Q_eTLPKdrHs]https://www.youtube.com/watch?v=Q_eTLPKdrHs[/video]
It will pave the way for bendable screens and moving wallpaper.
It's going to totally change the way we use batteries and power.
Mind you I pray you will be alive to see it.
I bet some people will still have old school double AA's hanging around though!