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AA Smartphone Charger Answered

Is there a way to charge a Smartphone using a single AA battery? I already have a DC-DC booster to 5V but the current is not enough to charge the phone, can someone please help me with this?

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Downunder35m
Downunder35m

4 years ago

A half decent smartphone battery has around 4500mAh.
A really decent AA battery might reach about of that, add the losses from the booster and you will see why it won't work.
As soon as the battery goes under the minimum of the booster it will be over anyway.
A decent motor, gearbox and hand crank is better than a AA battery ;)
Usually 3.7V lithium ion batteries are used for tis type of charging, although I would be tempted to add a connection so the battery can be used as "replacement" for the orignal - would save all the losses directly...

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Wihand
Wihand

Reply 4 years ago

Thank you for the information that you provided me it helped me understand this better.

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supernoodle2014
supernoodle2014

Reply 4 years ago

to extend this answer a AA battery has around 1500 to 2000 mAh at 1.5volts, equaling 3W of power. But alkaline battery's don't like to be discharged fast resulting in supplying less mAh at higher loads. The cell phone battery talked about above can hold 4500mah at a charge of 3.7 equaling 16.65 watts. So it would take over 5 AA battery's to charge this phone. This doesn't include any loss from the booster and Li ion charging circuit in the phone. So to sum it up AA's just aren't built to handle what a phone battery needs to charge. I hope that all made sense, good luck with your project.

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Yonatan24
Yonatan24

4 years ago

They can't supply enough current. Try using an 18650 battery. You can salvage one from an old laptop battery.