Making my own power bank

OX-49

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Nov 19, 2012
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Hi, I want to make power bank for my phone, tablet and laptop.
I have 15x 18650GR cells and 9x 17670GR cells
I am green on this, so any help required
 

OX-49

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I know that.
My laptop needs 3,42A 19V (asus)
Phone: S5
Tablet: Note 2014 edition

I need to know what modules should I buy/make to convert 3,6V into 5V or 19V and up to 3,42 A
I am thinking about 1 USB port for charging, mini USB port for recharging, and cable for Asus 19V
but for big batttery mini usb for charging is to small, so I don't know what to choose
 

Rvn

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Well, at least I wont recommend wiring all the cells in parallel and converting 3.6v to 19v 3,5A because that would mean your drawing over 17,5 amps from the cells, and they wont handle it. Wire likes 5 of them in series and those arrays of 5 in parallel and just get some step up and step donw converters to get the right voltages. But Im not a pro here either, 3.5A draw might still blow up the cells and im pretty sure it will, so... I dont really know what to do.
 

Rvn

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And I'd also recommend a basic DC jack instead of micro usb for a big battery likes that.
And also get protection circuits for your cells. You dont want them blowing from too high discharge rates or any other reason.
 

OX-49

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3xparallel cells connected sequentially which gives me 18V and 7800mAh
3-3-3-3-3

OR

4xparallel cells connected sequentially which gives me 14.4V and 10400mAh
4-4-4-4

Will this work? without explosion :D

Okay then, forget laptop.

 

Rvn

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Jul 10, 2015
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You should at least try the 5 in series 3 in parallel config... But it really depends on the quality of the cells. Some good cells can give 5A and some chinese one only reach an amp or so before dying. But if you wanna forget the laptop.... You could go all in parallel if you have good quality cells you could probably draw 5v 2a for the tablet. But Id still recommend doing it 2 series and 7 parallel so you can get faster charge rates more safely. And all you need is a 3,6 or 7,2 to 5v usb (Get a 2a one, its very frustrating when your trying to charge and only losing battery life) module off ebay or something. And a charger. But I'd still recommend protection circuits.