Does a 1S4P 18650 battery need balancing? I read a lot about balancing around the internet. To me it seems like this only applies to the cells connected in series. An all parallel setup would not need balancing. Is this correct?
Does a 1S4P 18650 battery need balancing?
No. In parallel they are electrically a single cell. You can't 'balance' a single cell.
However before connecting the cells together you should make sure that they all have close to the same voltage. If they are new then they should do, but if they are used then you may need to 'balance' them before making the pack.
Don't make a pack from cells of different capacity, type, age, or condition, as they will not share the load equally.