I picked up some $2.50 1x18650 DIY USB power banks from Banggood in the hope of finding something I could use for give-aways and gifts. I’ve seen similar devices on ebay, and elsewhere.
Long story short, while I like the compact size and aluminum shell, I judge it: teh suck. Pretty inefficient, high internal resistance, and charging cuts out prematurely.
For the nitty gritty, check the link above.
I like your mod!
Thanks!
It was a perfect use for some of the leads I’ve accumulated from laptop pack’s I’ve torn apart.
Thanks for the links to the YouTube review you posted in another thread. I added them to my post.
idk why but mine which is the same model like yours, gets overheated when charging up phones
Mine gets pretty warm too, not a big surprise since the stock version probably dumps 40% of the cell’s power, as heat. My mod helps, but its still burning 1/3rd of the cell’s power.
boost circuits are woefully inefficient for the most part…40% dumped in the conversion is a pretty normal number…I have seen some of these boost circuits efficiencies in the low 50%…yuck, but for higher efficiency requires more components/better components and those cost ALOT more than the cheap modules.
Like this guys DIY superbooster
http://longhornengineer.com/diy/super-boost/
http://longhornengineer.com/projects/pcb/super-boost-standalone/
I’m going to have to take a closer look at the output diode and the resistance of the inductor. These things have to operate at high frequencies in order to get by with a compact inductor, so it seems like other than avoiding unnecessary resistive losses, the next step is implementing synchronous rectification and replacing the output diode with MOSFET.