If we want our copters to perform as we expect them to, we need to provide them with enough electrical energy. In this section, we’ll focus on the types of batteries used in FPV drones, their characteristics, and safe handling practices.
Battery Types
There are many types of batteries, but for FPV drones, the most commonly used are LiPo (lithium polymer) and Li-Ion (lithium-ion) batteries.
- LiPo batteries are preferred for freestyle and racing due to their high discharge rates.
- Li-Ion batteries are sometimes used for long-range flights because they offer higher capacity at lower weight, but they cannot deliver as much current.
LiPo Battery Safety – What NOT to Do
- ❌ Never charge LiPo batteries unattended.
- ❌ Always use a balance charger and connect the balance lead.
- ❌ Do not fly in cold weather (below 10°C) without preheating the battery.
- ❌ Never short-circuit the battery terminals.
- ❌ Do not overcharge (max 4.2V per cell) or over-discharge (never below 3.3V per cell).
- ❌ Never puncture or crush a LiPo battery.
- ❌ Do not use swollen batteries — dispose of them properly.
Safe Charging and Storage
- ✅ Use LiPo-safe bags when charging or transporting batteries.
- ✅ Store batteries in fireproof containers (e.g. ammo boxes).
- ✅ Charge batteries on non-flammable surfaces.
- ✅ Monitor voltage during flight and land at 3.5V per cell to avoid deep discharge.
- ✅ Dispose of damaged or old batteries at designated e-waste collection points.
Disposing of a Damaged Battery
If you find that the battery is punctured after a crash, do not charge or reuse it.
A strong chemical smell (often compared to strawberries) is a clear sign of damage.
To safely neutralize the battery, immerse it in very salty water for several hours.
After that, take it to a designated e-waste collection point.
Never throw LiPo batteries into household waste or bury them in the ground!
Battery Parameters
Several key parameters define a battery’s performance:
- Capacity (mAh or Ah) – how much energy the battery can store
- Number of cells (S) – determines voltage
- Discharge rate (C-rating) – how much current the battery can safely deliver
- Charge rate – how fast the battery can be charged
- Internal resistance – affects efficiency and heat generation
Series and Parallel Connections
- Parallel connection: voltage stays the same, capacity increases
- Series connection: voltage increases, capacity stays the same The number of cells in series is marked with S (e.g. 4S = 4 cells in series). Each LiPo cell has a max voltage of 4.2V, so a 4S battery = 16.8V. Using a battery with too high voltage can damage your electronics. Balance connectors are used to equalize voltage between cells during charging. A 4S battery has a 5-pin balance connector, a 6S has 7 pins.
Discharge
Another important value is the discharge current, usually marked on the battery as a number followed by the letter C.
For example, a 1500 mAh battery rated at 95C has a continuous discharge current of:
1.5 × 95 = 142.5 A.
Some batteries also list a peak discharge current, which can be up to twice as high, but only for a few seconds.
Using a battery with too low a discharge rating can cause overheating, swelling, and damage.
Manufacturers sometimes exaggerate C-ratings, so it’s wise to check independent reviews.
Charging
Charging current is also marked in C-rates.
Most batteries are safely charged at 1C, though some modern ones allow 2–5C.
For example, a 1500 mAh battery at 3C = 4.5 A charging current.
Too high a charge current can overheat and shorten battery life.
If the battery gets warm during charging, reduce the current immediately.
For longevity, 1C is ideal.
Internal Resistance (Ri)
Batteries have internal resistance, measured in milliohms (mΩ).
As the battery ages, Ri increases, causing voltage drops and heat buildup.
Some chargers can measure Ri — useful for tracking battery health.
Storage Mode
New batteries are shipped in storage mode — about 3.8 V per cell.
If you won’t fly for more than a week, store batteries at this voltage.
Storing fully charged or fully discharged batteries shortens their lifespan.
Battery Connectors
Here are the most common power connectors:
- Banana Plug 4mm – up to 60–80 A, used for chargers
- JST – up to 5 A, used in small RC planes
- XT30 – up to 30 A, for small drones
- XT60 – up to 60 A, most common FPV connector
- PH 2.0 – used in Tiny Whoops
- BT 2.0 – improved version of PH 2.0, for brushless Whoops
Power Cables (AWG)
Cables are rated by AWG (American Wire Gauge). Lower AWG = thicker wire = more current.
- 18 AWG – up to 16 A (used in 2–3″ drones)
- 14 AWG – up to 32 A
- 12 AWG – up to 41 A (used in 5″ drones)
Chargers
Chargers can be:
- With built-in power supply (for home use)
- Without power supply (for field use, e.g. from car battery) Chargers should have a balancer to equalize cell voltages. Some are simple (LEDs), others advanced (discharge, measure Ri, multiple channels). Multi-channel chargers let you charge several batteries at once — ideal for FPV flying.
Balancer
Another part of chargers, as we mentioned above, is the balancer.
Chargers usually state how many cell batteries they are capable of charging — for example, 2S to 6S.
The balancer ensures that all cells in a multi-cell battery are charged evenly, which is crucial for safety and battery health.
And that’s all about batteries and chargers