Holy Feather 2PCS tp4056 Charging Module 5V Micro USB 1A 18650/16340/21700/26650/14500 Lithium Charging Board with Protection Charger Module with Dual Protection Function

This is a nice simple charging board for Li-Ion cells based on the tp4056 chip. The boards come stuck together (made from the same mold) and need to be snapped apart. You do have to be a little careful there, they were pretty firmly stuck together and it took care to snap them apart without cracking anything extra.No instructions are included, but it's easy enough to figure out; B- to battery negative, B+ to battery positive. I soldered these onto a few generic 18650 battery holders to make simple chargers to run off of a 5-volt solar panel, all sealed up in a waterproof junction box. The boards show a red LED for charging, and that switches to a blue LED when finished. Very basic, these have no percentage or voltage readouts, but it works, and they're doing great in my setup.I should mention that the tiny little tp4056 chip can get HOT, so don't burn yourself touching it! You won't notice it an inch or two away from the surface, but it WILL be hot, so you shouldn't touch it while in use, and should DEFINITELY plan to mount it where it won't touch the battery you're charging directly either!So yeah, plan how you want to set up the board in advance, but in operation this is simple to implement and works just fine, I've got no complaints.

I was working on a solar-powered Arduino project and needed something to help me charge my Bank of 18650 batteries. This board has filled the need without any issues.

These boards are a great way to bring battery power to any project.18650 cells are plentiful - and these boards are a good, relatively safe way to use them in your project. Solder the battery to it's two points, and your load to the other two, and you're off to the races. Monitors minimum charge so it doesn't draw your cell down too low, converts cell voltage up to a usable 5V, etc.

What i like about this charger is knowing the reverse polarity is functional. I checked the polarity of my battery before attaching it to this battery charger, and yet i STILL connected the positive to the negative and the negative to the positive */facepalm*. Luckily this device protects against that, and even though i did not plan to test that feature, I can say with confidence that it works!Other than my mistake, this is a great little charger, many of these 3.7v chargers are still using the old micro-usb port, but this has an updated usb-c port which i appreciate. After plugging in my battery correctly I saw the light on this device change from blue to red to indicate it is charging, i then went to bed and woke up to a fully charged battery.This charger does not come with pins so you will need to supply your own if you intend to use them on this device. I soldered 2 pins on mine and was happy to see it uses proper breadboard spacing. I love when circuit boards use this spacing because it makes it super easy to solder pins (especially when there is only 1 solder-able pin in each corner like these have). I had a bunch of 3.7v mini drone lipo batteries laying around so this was perfect for me. I did receive this product at no charge to review so if i have issues with it (due to my own negligence, or if the product is faulty), i will update this review. So far it has exceeded my expectations, and I'm happy to have it. I have a queue of batteries waiting for their turn, 2 down 5 to go.

These charging modules work pretty good!