I bought two cheap ebay DIY powerbanks, a buck for a one cell, and two bucks for a 3 cell (all 18650). Expected nothing, used laptop pulls from two years ago, amazed they both seem to work fine. Compared to my 1 cell 18650 fancy $8 Blitzwolf the construction is very cheesy, thin plastic etc, but both work with no issues so far.
One cell is the square aluminum body, pay attention it slides only into body ONE way and locks in on 4 screws in the face.
Three cell is flat, three cells across in parallel, rounded sides with a round button. Works fine with two cells so far.
Depends on what fails, USB ports so small are weak, the cells are cheap or old. If the cell is still good, and/or better aren’t plentiful I’m out a buck shipped.
Most of the ones I’ve seen are unprotected cells only there are dozens of different kinds go all the way to 8-10 cells. Most are a one way thing once you shut the case its meant to lock. Some you can get back open with some elbow grease but usually a one and done type thing.
Nah, I stocked up on the actual powerbanks when they were on sale for 5bux at MicroStore. Advertised LG cells. So I get the powerbank as-is to use as I see fit, and if the usb connector starts going mental, I strip it.
Get a nice low-mileage LG cell, the ubiquitous charger-board that can be used for projects, and a nice case with button for things like laser-pointers (18350) or other doodad.
I had some cheap powerbanks that you put your own 18650s into and 2 of them work great, the other let out smoke when I put the battery in… I don’t use them very often because I kinda don’t trust the circuitry, but they’re nice to have on trips.
If you have the cells then OK, but it is cheaper to buy Powerbanks such as xiaomİ or RAVPower Deluxe Series 10050mAh.
I have some of the DIY chargers and they work fine.
Jerry