Like stated already, maybe, depending on the BMS.
But the concept is just fine... I run several 36v doubled up packs. It's a great way to give 72v to a motor that could use some more volts for some more rpms with cheap, easy to get batteries and chargers. Now 72v is getting more available commercially, but that's a pretty recent thing.
Here's my heavy weight set up... 6 36v batteries in series for 3 72v modules, then paralleled up. I can also run off of just one module for light weight short range sprints.
I used to get lots of Pedego batteries from a recall, so the silver box at the bottom is a regular one still in it's shell, then a matching one out of its box paired up on the lower rack for 72v 14ah. Then 2 more that got deboxed, then split into long skinny shapes instead of boxy, but it's the same Pedego batteries as the bottom set for another 14ah.
The top set is a pair of Bosch batteries, also uncased, that I got for free because of defective BMSs, that are 10ah.
So that's a little over 3100 watt hours right off the charger, from 6 free batteries that would have gotten thrown away!
The pack looks huge (and it is!) but one plus I didn't anticipate was adding the last top module made it just tall enough to lay my chest on for long aero tuck sessions..so comfy suddenly!