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

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

Answer: Using 18650 Li-ion cells instead of LiPo batteries in an RC plane is possible but requires careful consideration. LiPo batteries typically provide higher continuous discharge rates (C-ratings) and lighter weight for the same capacity, which is crucial for performance and flight time. Here’s how to approach it:

1. Check the current draw of your motor and electronics. 18650 cells usually have lower C-ratings (around 5-10C) compared to LiPos (often 20C+), so ensure the cells can safely supply sufficient current without overheating.
2. Calculate the total voltage and capacity needed. Li-ion cells have a nominal voltage of 3.6-3.7V, so you’ll need to connect enough cells in series to match the voltage of your original LiPo pack (often 3.7V per cell for LiPo too, but LiPo packs are multiple cells in series).
3. Consider weight and size. 18650 cells are heavier and bulkier, potentially affecting your plane’s balance and performance.
4. Use a proper battery management system (BMS) to protect Li-ion cells, as they require balanced charging and protection against over-discharge.
5. Test carefully on the ground first, monitoring cell temperature and voltage under load.
6. If performance or safety is compromised, stick with LiPo packs designed for RC use.

In summary, while 18650 cells can be used, they are generally less suited for high-drain RC applications than LiPos. Prioritise safety and performance by ensuring the battery setup matches your plane’s power requirements.