Newcomer here and a total noob. Ok so coming to the question i am planning to build a battery bank with 18650 cells. I am opting for a 3s4p configuration as its closer to my operational requirements. I want to install a 3s 10 amp bms board without balancing function. Also i shall install balancing leads in such a way that they can connect to 3 individual TP4056 boards with isolated power supplies. First using a constant current source connected to the bms power leads, i will charge the bank to approximately 12.0 volts. Then when the power supply cuts out i want to finish off the charging process throught the TP4056 modules with the goal of obtaining a balanced charge on all 3 cell groups. Will this work? Have i gone horribly wrong and i stand the risk of the whole contraption blowing up in my face? Kindly help!
Using a switching power supply, and adding more batteries than you would otherwise need would keep the voltage from dropping much under heavier load. Also, if you have the option, using larger batteries (higher mAh), in series would be the best option without any doubt. This is a perfect instance where you would REALLY want to use a high efficiency Switch Mode Power Supply, (SMPS). This will give you over 90% efficiency, especially if made well. You will find parallel or series parallel configs very short lived, as batteries are notoriously unequal in voltage, especially under load.
To begin with, batteries in parallel is almost always bad practice, for reasons I won't go into now. Go with series.
2nd: for even the most simple stuff, it is always best to include a schematic, and a detailed description of what you are trying to accomplish.