Chapter 09 · Components
All about LiPos
A well-treated battery lasts hundreds of cycles; a mistreated one puffs up within weeks or, at worst, catches fire.
The voltages you need to know
Check a battery’s state on the spot with the per-cell voltage calculator.
Battery types
| Type | Character | Use |
|---|---|---|
| LiPo | Lots of instant power, moderate weight | Freestyle and racing |
| LiHV | LiPo that charges up to 4.35 V per cell | Small drones (1S, 2S) |
| Li-ion | More energy per gram, less current | Long range and relaxed flying |
How to read a label
6S
Six cells in series: 22.2 V nominal and 25.2 V fully charged. If you see “2P”, there are two cells in parallel in each group.
1300 mAh
The capacity. More mAh means longer flight time, but also more weight, and you feel the weight in how agile the drone is.
120C
Theoretical maximum current = capacity × C. Many brands inflate the figure: only compare it within the same brand.
XT60 / XT30
The connector. XT60 for 5"; XT30 for 3–4" drones; BT2.0 or PH2.0 for 1S whoops.
A 5" uses 6S packs of 1050–1300 mAh, or 4S packs of 1300–1500 mAh.
Charging
- Always in balance mode, with the small balance lead plugged in: that way all the cells end up at the same voltage.
- At 1C or less: a 1300 mAh pack at 1.3 A. It takes about an hour.
- Wait for it to cool down after flying before you charge it.
- Never leave it charging unattended, and charge it inside a fireproof bag or box.
- Parallel charging with a board is handy, but all the batteries must have the same cell count and similar voltages.
Choosing a charger
Features
Balancing, storage mode, discharge and internal resistance readings.
Power
Power (W) = voltage × current. A full 6S at 1.3 A needs about 33 W; for several at once, much more.
Power supply
DC chargers need a power supply. AC chargers plug straight into the wall.
Making them last longer
- If you’re not flying for a couple of days, leave them at storage voltage.
- Don’t discharge them below the limit or let them get too hot.
- Store them at room temperature, never in the car in the sun.
- Internal resistance is the best indicator of health: if it rises a lot, the battery is getting old.
- Always hold them by the body, never by the wires.
Battery logbook
Note down the cycles and, if your charger measures it, the internal resistance (IR) of each cell. Over time you’ll see which batteries are ageing and which cell will fail first, before it leaves you stranded mid-flight.
The data is saved only in this browser. Export it every so often, or to move it to another device.
When it reaches the end of its life
Retire it if it’s puffed, dented or punctured, or if it has lost a lot of capacity. Fully discharge it with the charger in a safe place and take it to a recycling centre or a battery collection point. Never throw it in the bin or puncture it.
In case of fire, don’t use water. Use sand or a suitable extinguisher, and keep away from the smoke, which is toxic.