For those who do not know, a power bank is nothing more than a portable energy storage system that will allow us to load our mobile, tablet, etc. wherever we are (if previously we have loaded the Power bank). Usually come with a USB output where we can connect our charger cable.
The most important of our powerbank is going to be to obtain a USB output with stable voltage to 5VDC and that is able to give current enough to load our gadgets without Eternizarnos, for it we will use this small plate:
As for the current, it is able to supply up to 1a, so we will be worth to load any gadget at a decent speed. In the tests I’ve done at no time have I noticed overheating on the board reaching currents near the amp.
Storing energy in our Powerbank
To store the energy in our powerbank and then give it to our gadgets we have opted to use a lithium battery type 18650, da 3, 7v and can store near 3000mah, which will allow us to load a normal smartphone without problems.
If you want you can use two 18650 in parallel to increase the stored energy. These batteries should be the same and both new as if we could not have problems downloading one on the other.
Loading Home Power bank
Now that we have the energy storage and the way to deliver it to our gadgets, we only lack the burden of our homemade power bank, for this we will use this other plate that you can buy for €1.4 here (Free shipping).
This is a plate that regulates the charge of a battery like the one we are going to use, has microUSB input so you can use a normal mobile charger. Its main features are:
- Max load Current 1A
- Full-load Cut: 4, 2v
- Overload Protection: 2 .5v
- Over-current Protection: 3A
The last two protection features are very interesting as they will prevent our 18650 battery from coming down below a voltage where it would be damaged and also protects the same from a possible short-circuit.
The installation scheme of our homemade powerbank is very simple, it would be something like this: