Homemade SmartPhone PowerBank

Dear All,
I want to make a smartphone powerbank using 7.2V 2500mAh rechargeable battery pack to charge my HUWAWEI smartphone with 2000mAh 3.8V battery. Is it possible and effective? and please tell me how.

Hi,

I'm sure it's possible and effective with sufficient research and diligence.

You'd need something like an LDO (paying attention to the current it can really provide with 7.2V - 3.8V * required charging current) or a Buck Converter IC might be more suitable, and probably the best choice would be a battery charger IC.

Whatever the charger is that comes with that phone, it should give you a good/guesstimate indication of the charging current.

A first point of call is knowing what the 'phone battery chemistry is and basing the project on that, unless it is also necessary to make the charger for the powerbank battery, then it is necessary to understand the needs of that battery too before doing anything that is pointless or that risks damaging either battery or people/houses.

Probably searching online to try to find out how the charger and phone battery relate to each other will be a useful way of starting the project, if Huawei don't have in-depth material, probably not, you may get lucky on a 'phone fan website or somewhere like YouTube with a repair/breakdown video, it's just a thought...

Reading about powerbanks is a must-do too, if you haven't already.

May be an idea to use any of the free simulation programs available to explore the circuit before making it.

Personally, if I were to make that and could afford the parts, after researching it all so as to understand the concepts myself at least minimally, I would go with the relevant battery charger IC, and possibly test it out on a dummy 'phone, for example a circuit that would use the sam voltage and current, before doing something that ends in tears and a broken phone with no warranty due to user "misuse".