My micro-usb port on my phone is no longer functioning. So instead of buying a new phone or waiting weeks for a cheap battery power bank to come in from China (stuck for cash), I was thinking of making my own.

I have this Anker multi-port charger here

I noticed it is certified safe, but I'm not entirely sure what this implies:

"Certified Safe: Anker's MultiProtect safety system ensures complete protection for you and your devices. Worldwide 100-240 volt AC input voltage."

Now, if I was to plug a usb cable into this power source, snip it, and connect the appropriate wires to their respective +/- connections on the battery, will it charge up safely?

Assuming I don't let the cables touch, and I do everything right etc.

I saw this done on the internet but saw a comment saying that the battery will over-charge which is not healthy for the battery.

But I was thinking maybe this Anker "intelligent" multi-port power source would eliminate this problem.

What do you think? Thanks for any answers!

(Really don't want to have to buy a new phone or battery bank)


closed as unclear what you're asking by Leon Heller, PeterJ, Daniel Grillo, Brian Carlton, Matt Young Jun 22 '15 at 20:39

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No, you can't simply hook up USB power to a phone battery and expect it to charge safely.

Phones typically use single-cell rechargeable lithium batteries, which have a voltage of around 3.7 volts, while USB plugs provide 5 volts at (typically) up to about 500 milliamps. Further, LiPo and Lithium Ion batteries require a careful charging profile - first charging them with a constant current, then with a constant voltage, until they're full. There are dedicated charge control ICs specifically for this.

If you directly attach USB power to a battery, the most likely result is that it will heat up, and eventually explode, rupture, or catch fire. If you're lucky, the PC or "intelligent" device it's connected to will detect an over-current condition and shut down before that can happen.


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