Choosing A Lithium Polymer Cell Size

The Model Number Is The Size

A lipo model such as PL603048 reads as 6.0mm thick, 30mm wide and 48mm long. That is the bare pouch. The dimension we publish in the model list, 6.2*30.5*50.5mm for that cell, is the size with the protection board fitted, which is the number your enclosure has to accept.

Allow For The Board And The Tabs

The board adds roughly 2mm to the length and a few tenths to the thickness and width. Designing to the bare pouch dimension is the most common mistake we see.

Capacity Follows Volume

Across our published list, capacity tracks volume closely: PL401121 at 60mAh is a 4.2 by 11.5 by 23.5mm cell, PL755070 at 3000mAh is 7.7 by 50.5 by 72.5mm. If the space is fixed, the capacity is close to fixed too.

Electrical Basics

3.7V nominal, 4.2V charge voltage, 3.0V discharge cut-off, around 500 cycles, and a standard charge current of 0.2C.

When To Use A Cylindrical Cell Instead

If the space is a cylinder or a deep pocket rather than a flat rectangle, an 18650 usually gives more capacity for the same volume and a lower cost per watt hour.