A while ago I had an idea to make an 18650 lithium cell charger out of a series of single-cell TP4056 charging modules.  Before I completed it though, I came to realize that every other 18650 hobbyist out there had the same idea.  No big deal, still need one.

I initially wanted to design a slick 3D printed frame for it, but I was getting hung up fleshing out the concept.  So I abandoned that and just hacked it together out of whatever was laying around.  Mainly a chunk of 2×4, a piece of baseboard trim, some aluminum channel, and a few sticks of one-bys.



I glued the modules on the aluminum bar.




Then it was time to start soldering wires to the modules.



I just used what wires I had on hand, cat 5 ethernet cable, but I wouldn’t use them again.  They’re too brittle and break too easy.



I hooked up these little amp meters to each bank of four cells, just to keep tabs of what each group is doing.



Kind of a mess on the bottom.




I’m plugging it in to my 40 amp 12-volt power supply.  Master switch on the left, then it goes to the 15-amp dc-dc converter to dial the current down to 5 volts for the charging modules.  There’s a volt meter just above the power switch that displays the output of the dc buck converter.  Then it’s the amp displays, TP4056 modules, cell holders, and a fan on the right.  The charging modules get pretty toasty so some airflow is nice.



It has been working really well.