[Q] What can a iPhone 3's battery do ?

[ImbaWind]

I got a iPhone 3's battery and I'm wondering what it can do.
I intend to turn it into a external battery bank but I have a few questions:

1. The battery is rated as 3.7v, can I use my pc usb to charge it directly?
2. If I want to use the battery to charge my phone, what do I need ?

 

[showlyshah]

http://forum.xda-developers.com/showthread.php?t=1401627http://forum.xda-developers.com/showthread.php?t=1401627
Sent from my HD2 using xda premium

 

[qubas]

1) No, you need IC to manage charging process of Li-ion/Li-po battery, for example: MAX1555.
2) You need to get stable 5V out of it. In case of single cell (probably 3.7V rated) only reasonable possibility is to use DC-DC converter in order to boost voltage.

I think that trying to make phone charger out of it is not worth the effort, however it should be relatively easy to use it with circuits that require ~3.3V, maybe a LED flashlight?

 

[showlyshah]

1) No, you need IC to manage charging process of Li-ion/Li-po battery, for example: MAX1555.
2) You need to get stable 5V out of it. In case of single cell (probably 3.7V rated) only reasonable possibility is to use DC-DC converter in order to boost voltage.

I think that trying to make phone charger out of it is not worth the effort, however it should be relatively easy to use it with circuits that require ~3.3V, maybe a LED flashlight?

The above link, i managed to get 5v out of a 3.7v li-ion. The ic can provide 5v o/p from 1.5v i/p and the amp rating is 500ma, u can add low battery led,status led and charging led indicators if needed( i put those). The best advantage is if u use a protected li-ion cell as donner cell, u can connect any battery charger to the Donner cell, 4v-6v will work.( u only need a suitable connector for plugin the charger( i used a nokia connector, lol i can find it every where i go).

Sent from my HD2 using xda premium

 

[qubas]

Nice project showlyshah.

I guess it all depends on how much effort and money ImbaWind wants to put into this. You have to choose and buy components, design circuit, probably design and etch/order PCB and finally assemble everything. It will take at least several hours and cost more that off the shelf battery bank. If you think you will have fun while designing and building it, then why not