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Help needed desperately ! (Question related to batteries) Answered

Hi Guys,
             Recently I planned on making an portable phone charger the classical way, with a car phone charger. But then I came across the problem of choosing a battery. The 8 AA batteries way is not economical, as I will be charging a Sony Xperia Z1 and it will drain the batteries in one charge. The 8 AA rechargable battery method will be better but will set me back about $20 so that's a no. If I use a 9 volt battery it will charge the phone 20%. The final and the most stupidest method is to connect 10 9v batteries so that I get 9v 4 amps but that will be too bulky. Lithium batteries are useless as I will get the required amperage but the voltage will be too low and the other ones will once again set me back too much. So the only way is to use 8 AA batteries but every phone charge will cost me approx. $1. Is there any other cheap way or 8 AA batteries it is?

Thanks in advance :).

Discussions

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rickharris

Best Answer 3 years ago

A lipo (lithium) battery can be configured in many ways and produce very high voltages and current.

typically for the radio control world there are many options.

A single cell gives you about 3.7 volts

http://www.hobbyking.co.uk/hobbyking/store/__56840...

is a 4 cell high power 5 amp! battery pack about the size of your mobile phone - Certainly lighter and more compact then 8 AA batteries. The gives 14.8 volts allowing you to regulate down to the 5 volts you need. A car battery when charged will be around 14 volts.

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rickharrisThe Prickly Potato

Answer 3 years ago

BUT 35 charges down the road you will have broken even and the Lipo will charge perhaps 1000 times.

You have the answer pick the one you like!

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-max-

3 years ago

In this video, I have covered a far better method for charging a phone with a 9V battery (compared to an inefficient 7805 linear regulator), although I have not tested it to see how far from 0% I can charge a phone. I predicted close to 27%, so I was not too far off.

But you'd be right. What I would do is but a small high capacity 3S battery, or get 3 phone batteries of like 3000mAH and wire them in series, and use a buck converter like the one inside the car charger plug in the video. You can see that it would be 9000 mAH @ 11.1V which, in terms of WH, the basicly the same as 9000 mAH @ 3.7V. Even if you take only 80% of that taking into consideration a approximation of the efficency of the buck converter, that is plenty of juice to charge a phone up a few times from 0!

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steveastrouk

3 years ago

What's the point of this ? You appear to have no interest in investing anything in a solution to the problem ! You COULD use a single LiPo battery, and a boost charger. And how can you buy 10 9V batteries for less than 10 dollars a set ?

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Downunder35m

3 years ago

If you don`t want to spend money on proper batteries and charging electronics I see only two options for you.

a) get a spare battery for your phone and change over once the first is empty.

b) get a hand crank generator and well, crank it.

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Wired_Mist

3 years ago

Well on one hand you can use 8 Re-Chargable bateries !