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Homemade power bank - doubts

rjng

Jul 6, 2013
10
Joined
Jul 6, 2013
Messages
10
Hello friends,

I was looking for a cheap power bank to buy, but I've thought make one could be a nice idea. But many problems came in mind.

There are many kind of DIY power bank modules selling in the internet. Look:

- http://s.aliexpress.com/eymUNvIZ
- http://s.aliexpress.com/UNvQnyUZ
- http://s.aliexpress.com/quaiiu6r

My idea is buy one module and use some 18650 batteries. Nice. Or not?

Well, I asked to sellers How many batteries can I use in each module. One told me 4, other told me there isn't a limit. What do you think? Many batteries will taken a long time to charge, but it's ok. But, will the module show the correct state of charging? Can the module deal with different charging state of each battery?

I extended my doubts to the problem of connecting batteries in parallel. When the module is off, the problem of one good battery charge a bad battery and it creates a great current could occour? Will I need to connect resistors among batteries? Would it occour even with protected batteries?

So I'm afraid to create a bomb instead a power bank.
There are some DIY power banks selling too. Look:

- http://s.aliexpress.com/v2MNfmIZ

The first problem I found in this product is my protected 18650 batteries don't fit the space for batteries. Protected batteries are bigger. But, my fear about parallel batteries wouldn't occour with this power bank too?

Maybe one solution is give up my idea and buy a better DIY power bank, like this:

- http://www.tomopowerbank.com/shop/tomo-power-bank-v8-4/

It isn't cheap as I want but maybe it's saber. And I don't explode my house.

I would like to ask your opinion. Is my idea to create a power bank from a module a bad idea? Could it bring me problems? What care do I need to take?

Thanks guys!
Rafael
 

oz93666

Dec 7, 2014
38
Joined
Dec 7, 2014
Messages
38
Have you looked on Ebay? there are literally over a hundred different products there , with better explanations of what they do than ali-express give...

My thoughts are buy a complete package
 
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