21700 Li-ion Batteries & Cells
3 products
Also in 21700 Li-ion Batteries & Cells, currently out of stock
21700 cells are lithium-ion cylinders 21mm across and 70mm long, and they power long-range FPV quads, mapping drones and radios that need flight time more than punch. This page covers every 21700 product in our Li-Ion Batteries & Cells range: loose cells for building your own pack, and ready-made packs from 2S to 8S. Two numbers matter most: capacity, typically 4200–5000mAh per cell, and continuous discharge current, which must cover what your motors draw at cruise and on climb-out.
How to choose 21700 cells or packs
- Cell: the Molicel P45B (4500mAh) and P50B (5000mAh) are popular high-discharge choices for FPV long range, and the Samsung 50S (5000mAh) is a common pick for larger packs.
- Configuration: "6S2P" means six cells in series and two in parallel. Series cells set the voltage (25.2V fully charged for 6S); parallel groups add capacity and current.
- Discharge: Li-ion delivers far less current than LiPo, so size the pack so cruise current stays well inside its rated continuous discharge.
- Connector: most packs here use XT60, while the large Samsung 6S3P and 8S3P packs use an anti-spark XT90.
What we stock
Loose cells include the Molicel INR-21700-P45B and P50B. Ready-made packs include Samsung INR21700-50S packs in 3S2P, 6S2P, 6S3P and 8S3P layouts, the Flywoo Explorer 4S2P 9000mAh built on Molicel P45B cells, Indian-made Revogreen 4S and 6S packs from 4200mAh to 10000mAh, 6S1P and 6S2P packs on XT60, and a RadioMaster 2S 5000mAh radio battery.
Compatibility
Li-ion packs suit efficient builds with modest current draw: 7-inch and larger long-range quads, fixed-wings and mapping multirotors on low-KV motors. They are a poor fit for 5-inch freestyle, where hard punch-outs make the voltage sag heavily.
Set your flight controller's low-voltage warning lower than for LiPo: Li-ion can be run down to around 3.0V per cell under load, against roughly 3.5V for LiPo. Charge on a charger with a Li-ion mode (4.2V per cell), and balance-charge packs that have a balance lead.
When building your own pack, use cells of the same model and batch, and spot-weld nickel strip rather than soldering directly to the cells.
Frequently asked questions
- Li-ion or LiPo for a long-range drone?
- Li-ion packs hold more energy for their weight, so they fly longer at a steady cruise. LiPo delivers far more current for punch-outs, so many long-range pilots fly Li-ion for distance and LiPo for freestyle.
- What is the difference between the Molicel P45B and P50B?
- The P50B is Molicel's newer, higher-capacity cell at 5000mAh against the P45B's 4500mAh. Both are high-discharge cells suited to drone packs.
- Can I build my own 21700 pack?
- Yes, with a spot welder, nickel strip, a balance lead and proper insulation; never solder directly to the cells. Use matched cells of the same model and batch in each pack.