Can I Replace LiPo Batteries with 18650 Li-ion Cells in an RC Plane?

Question: Can I use Li-ion 18650 cells instead of LiPo in an RC plane?

Answer: You can use 18650 Li-ion cells in an RC plane, but there are important considerations. LiPo batteries are designed for high discharge rates, which RC planes require for good performance. Most 18650 cells have lower continuous discharge ratings, so ensure the cells you choose can safely deliver the current your motor demands. To do this, check the cell's maximum continuous discharge (measured in amps) and compare it with your motor's peak current.

Next, you'll need to arrange the 18650 cells in series and parallel to match the voltage and capacity of your original LiPo pack. For example, a 3S LiPo pack (11.1V nominal) requires three 18650 cells in series (3 x 3.7V). Add parallel groups for higher capacity or current capability.

Also, use a proper battery management system (BMS) to protect the cells from overcharge, over-discharge, and balance charging. Li-ion cells are more sensitive to damage than LiPos. Finally, consider the increased weight and size, as 18650 packs can be heavier and bulkier, affecting flight performance.

In summary, 18650 cells can work if you carefully match current ratings, voltage, use a BMS, and account for weight differences.