How to make power bank with 8 rechargable AA batteries?
i'm a nobody at electronics, electricals and stufs. well i have some rechargeable batteries for some reasons,. 2 of my friend has a portable power bank for their phone. then curiously thinking if i can make that kind of stuf.. (DIY),.. if it possible please help me make this... my AA batteries is 1.5V with 500mah of power if i'm right. , then multiply by 8 so that will be 12V with 4000mah of power? right?. then i want this to charge my phone... recently searching i need to drop the voltage to 5, because if not, my phone battery will or might explode., then my phone will be damaged?.. so i need to make a circuit,, then that my problem, i dont know any thing about resistors and things like LM317, just i don't know anything about that.. i need it be able to be recharge and charge my phone,
so here's another question, expect the wee did make something like that, then how will i be able to charge it?, it's 12v right from the inside? right?..
that all, hope we can make something like this,, if there's a related post, which has been already answered, if this is not possible.. That all.. Advance Thanks for helps...