Which is better, one 12v 200ah battery or 4 x 3.2v 50Ah battery?

Under normal use, one 12V 200Ah battery is better than four 3.2V 50Ah batteries.

The reason for this is that when you have four 3.2V 50Ah batteries in parallel, they will not be exactly at the same voltage level. This Abnormal Voltage Gap can affect the life of the remaining three batteries if they are fast-charged.

Because of this, industrial batteries such as 12V 200Ah and 12V 50Ah are usually equipped with a BMS (battery management system) to achieve built-in balance to avoid abnormal pressure drop.

However, if you want to use modular batteries instead of single-piece ones, then you can also refer to the modular battery. The battery is made up of many battery modules in series and in parallel, and self-balancing is achieved through BMS. For example, the 12V 7Ah modular battery can reach up to 4S10P (48V 70Ah), which means that it has been configured according to the needs of users without worrying about harming the battery.”