Hello friends,
My name is Rafael, I'm new here.
I was looking for a power bank to buy, but I cannot find one that satisfied me, for a good price. So I've thought make one could be a nice idea. But many problems came in mind.
I'm not a technician, but I can understand something about electronic. So I searched many topics in many foruns, and electronic sites about batteries and chargers. The result is few answers and many doubts.
If I want to make one cheaper charger, I will need a module board. 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 would be 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 charging 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? (in principle, I want to use protected ones)
So I'm afraid to create a bomb instead of a power bank.
There are some ready to use DIY power banks selling too. Look:
- http://s.aliexpress.com/v2MNfmIZ
- https://www.fasttech.com/products/0/10007172/1590401-single-usb-pcb-board-plastic-enclosure-for-power
The first problem I found in these products 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 even with these power bank too?
I don't know if the idea of making a good and safer power bank is practicable for me.
So, is there a good module in market that can deal with some batteries, even in parallel? Do you recommend this kind of DIY project? (I've saw some guys here making thein own power banks and it seems to be all right with them).
If I give up the idea, maybe the best option I found is TOMO V8-4. Although some guys had experienced not good results with it, Maybe it can be a nice choice ( $ 13.49 now in gearbest). And, complementing, you know Soshine E3 (almost the same as TOMO V8-4). In discussions and reviews here we could see it need some improvements. Do you know the new version E3S (http://www.soshine.com.cn/a674.aspx) ?? The LCD is different, and maybe there are software and hardware improvements, but I cannot find any review of it.
Thanks guys! Sorry for being so long.
Rafael