Review on 4-Pack 18650 Battery Charger Protection Module, Power Bank PCB Module Board, Dual USB 5V 1A 2.1A with BMS Protection for DIY Phone Mobile Power Bank by Aleksandre Crane

I like the LCD panel. While these boards work great with the lithium batteries they were designed for, I've found that despite some differences in the way they charge, they also work well with nickel-cadmium batteries. I had a pile of nickel-cadmium batteries from dead power tools and laptops (usually there was only one bad battery in the pile). Since the NiCad charges to around 1.4-1.5V I connected 3 of them in series to charge to 4.2V (charging voltage for 18650 lithium batteries). While the NiCd series can charge up to 4.5 V, the board's charging voltage of 4.2 V is sufficient even if NiCd batteries are not fully charged. I put 12 of these in a homemade USB charger (4 sets in parallel, each set is 3 cells in series) and it works great (don't mix lithium and nickel cadmium batteries in the same charger). Again, the board isn't designed for nickel-cadmium batteries, so if there are any problems, it's up to you (I stopped having them after a few months of use). The only caveat is that these boards are sensitive to high heat (I'm sure other boards will be the same). I found out about this because I had sealed the batteries in an acrylic case, which generated a lot of heat inside the case, and the circuit board, which worked fine before being sealed, subsequently died. With normal use they work great and are accurate. Since I keep finding and storing Nickel Cadmium and Lithium batteries and can't throw away good ones, today I'm buying another set of these boards to make more powerful chargers to give to grateful family and friends.