I, like all of you I bet, have tons of USB power banks laying around, but even my largest, a "20,000"mah pack died after a few days away camping just charging my Apple Watch and iPhone. I wanted something that would last MUCH longer and be more versatile at the same time.
As this is the 21st century, we have the Internet which allows you to harness the brain of people with skills you don't poses, this means following some online guides of how to DIY the battery side of things. I then designed this enclosure around the pack, with some added features too!
The enclosure contains all the holes needed for a on/off button, a charge port, a LCD battery level indicator, 4x 2a USB ports, 4x USB Quick Charge Ports & two USB-C ports too. All those additional hardware items the case is designed around are linked below.
So, you want one too?
To actually build the power banks electronics, I used this guide
https://www.instructables.com/id/DIY-Professional-18650-Battery-Pack/
I suggest you follow that, build up your pack, make sure it works and then order all of the parts needed for this enclosure.
This is version 3.0 of my original design(V1 https://www.thingiverse.com/thing:3538397) (V2 https://www.thingiverse.com/thing:3858748) to keep all the same benefits of my older design with some small spacing and sizing improvements, but be compatible with the Vruzend 1.6 battery system.
I dont have any of the newer Vruzend kits, but in theory it should be compatible as long as their sizing hasnt changed. The Vruzend kits are amazing, they let you literally clip and bolt together a battery pack. This means that even if you don't have a spot welder, you can make your own 18650 power bank! Seriously, ANYONE can do this!
Performance
In my mixture of recycled 2500-3000mAh cells from old laptop battery packs that I dismantled, i achieved a total capacity of 40,000mAh of total charge output. This was tested using a 2 amp dummy load and a USB power analyser in-line. Obviously, using higher (such as all 3000mAh) or lower capacity cells will result in different capacity numbers and drawing current in smaller bursts, giving the cells time to recover slightly would likely have yielded over 40,000mAh. Also, this is true numbers, my "20,000"mah pack simply isn't even close to these figures in reality, 90% of the sellers online significantly over-rate their packs size. Just sticking in 8 2500 mah cells does NOT mean you have a 20,000mah pack as the cells are arranged in series parallel and you have losses from the conversion to 5v.
I have created a wiring diagram for you to follow when assembling the power bank. This is attached to this Thing.
As always, be careful! 18650's pack a punch, let alone when you have 28 of them hooked together!
There are two lid designs too. One is solid and the other has a raised edge. I personally used the raised edge one and filled the inside with casting resin. This gives you a smooth, glass-like top surface rather than the rough PLA layer lines. If you want to do this, use the file called "lid.stl", if not, then use "lid_NonResin.stl"
computerstar2000
