I’m starting to focus a little more on batteries now that I have most of the components for my 18650 discharger/tester and I’ve got about 1/3rd of the cells I need. I have previously made a large 18650 charger out of TP4056 modules, but these aren’t very good and require a huge 5v power supply. They don’t start charging if the cell is above a certain threshold (which is nowhere near full) and are a bit “delicate”.
I’m not sure when they became available, but courtesy of a friend from HSBNE (Australia’s largest community workshop), I found the excellent TP5100 modules. These take a wide input voltage (5v up to 12v) and support charging up to 2S (2 cells in series). I’m only interested in charging 1S, but the 12v input and higher charge rate was appealing so I ordered 40 of them.
I must admit that I “fried” a few of them before working out that the labels on the PCB are wrong! The input and the output are actually reversed. This was annoying, but for less than $1/piece I wasn’t too bothered. In the picture I took below, you can see the correct labels. Make sure the 5-12v input is always on the side with the large black surface mount inductor. The positive and ground labels seem to be the correct orientation.
Now onto the TP5100 “charge-o-saurus” that you came here to read! My intention was to originally use a single large piece of plywood and attach all of the TP5100 modules to it. However to make it easier to transport and minimise the chance of any wiring problems etc. from taking out all of the modules, I split them up into 8 module boards. I then put an XT30 (my new favourite connector for low to medium current draw applications!) on each one.
After I finished gluing each 18650 holder and TP5100 to the board, I then used some 18awg wire to hook everything up. Out of convenience, I soldered the positive pad on each TP5100 module directly to the 18650 holder. Be careful if you want to do this as it’s more difficult to get a good reliable solder joint.
When each board was completed, I hooked each one up separately to a bench power supply. This was to make sure everything was wired correctly and to test each one before hooking them all up. Once I was confident each board was working correctly, I made an XT60 > 3 way XT30 adapter. This allowed me to hook up the 3 boards to my modified server power supply that can provide 12v at around 70 amps.