I don't know if I can do this and just want to make sure that it can work before I actually test it so that I don't have to worry about blowing my room up… The batteries have the same capacity so there won't be over discharge or charge on each battery (I will connect a battery protection on the ends of the series). The charger that I used is TP4056. The batteries that I use are actually 18650s but I accidentally wrote LiPo in the schematic.
simulate this circuit – Schematic created using CircuitLab
Best Answer
This would work with a charger where the output is isolated from the input, but the one you link to is not isolated so definitely no.
I found this diagram
here which shows the issue, the low side is common through the module, so connecting as you show will short out the right two cells.
What you would need is a dc-dc switching converter with a dual wound inductor that lets the secondary side float, but I don't see one readily available, there are modules for 120V input that have this arrangement, since isolation from the mains is obviously important.
A better aproach is to get a single regulator module for the whole chain, which also has charge balancing between the cells to ensure that one doesn't get over- or undercharged.