Not if its really dead. I used to try to do that with AAA batteries (my mp3 used those) but it only raised the energy very slightly and it doesn't work if its completely out. But a phone and a tablet and those kinds of things need a certain amount of energy just to start up. That amount can't be conjured with magick.
I cannot help with this problem. I have no idea what a phone tablet is! All this new technology is rather beyond me. I don't really know how to use my computer fully! I am only just getting used to a ball point pen! Having used a fountain pen all my life!
Ah, if only I was young again, and knew what a phone tablet is!
Spell to recharge tablet
Connect the recharger to electricity, then connect the Phone tablet to the recharger. Go and do something else for a hour or two.
99.9% chance of success.
the energy in magick is different from the energy in batteries. think of it like this, there are electrical impulses in your body, different from lightning or electricity in your home, when you are tired you are 'low on energy' so do you stick your finger in an electrical socket to 'recharge' or do you grab a cup of coffee? same thing with electronic devices, you wouldn't pour coffee on it to recharge.