Such a small question with so many variable.
It all boils down to the ability to replace if needed, and quality of the cell and price.
Sometimes the cells block will LVC because one or more parallel cells are not up to it and this is cheap to replace smaller cells.
In comparison.
Small parallel cells
Many have said two
series parallel packs can be better than one larger one, as it gives you more options. You can split them. Well the same applies with paralleled cells. Can be difficult to repair.
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Larger cells
Certainly 20ah lithium cells would be an awesome own. Less infrastructure to wire them up. The load is limited to a single current path at the terminal, again has advantages and disadvantages. easier to repair, Lithium batteries just keep getting lighter. A lot more expensive to repair and replace.
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There are argument to both sides.
If you were to buy budget and wasn't sure of the quality, parallel cells are a good way to go.
If you got big bucks and a good solid warranty then larger cells are stylish and sexy.
