Can a Flip Phone Be Converted into a Portable Battery Pack?

[requiem31]

So I have an old flip phone here that I wanted to turn into a portable battery pack because its winter break and I am bored. Whole thing is apart and good to go but I was wondering if there is any way to reverse the current. Obviously charging it one way, and then when you use it as a battery pack reverse it.

 

[meBigGuy]

the way most battery operated systems work is that they draw from the battery when they are not charging, and from the charging source when they are charging. If you try to draw from the battery when it is being charged (by connecting to it manually), you will mess up the charger profile.

You need to try to reverse engineer the battery control system and determine where to connect to get power properly. But it will probably be a regulated voltage, not raw battery.

But, the circuit could be different than what I described.

I'm not sure precisely what you want to do, but it probably isn't worth the trouble when you can buy a 10,400mah high quality battery powered usb charger for <$25 (see
Xiaomi Mi Power), or even less.