Understanding FPV Drone Types and Their Ideal Batteries

Introducción

FPV drones come in a wide range of frame sizes and flight styles: tiny indoor racers barely larger than a smartphone, nimble sub-250 g quads that slip past registration rules, powerful 5″ freestyle machines, and endurance-focused 6″–7″ rigs. Regardless of category, one constant remains: you need a battery that balances energy capacity, discharge capability, and weight to match your frame and motors.

Lithium polymer (LiPo) batteries reign supreme in FPV because they deliver high current (high C-rating) in a lightweight, flexible pouch. Unlike cylindrical cells, LiPos can be made flat and shaped to fit under a flight controller board or behind a canopy. Their discharge curve—from 4.2 V per cell down to roughly 3.2 V under load—provides predictable throttle response. In this article, we’ll cover:

1. FPV drone types and typical frame sizes.

2. LiPo battery fundamentals: voltage (S-count), capacity (mAh), C-rating, weight.

3. How to match LiPo packs to each drone type (micro, sub-250 g, freestyle, cinewhoop, long-range).

4. Key considerations: thrust-to-weight, voltage sag, pack placement.

5. Real-world case studies comparing common LiPo setups.

6. Battery maintenance and safety best practices.

7. 21700 battery pack: new battery solutions

---

Overview of FPV Drone Types & Frame Sizes

FPV drones are often categorized by frame diagonal (wheelbase) in millimeters or by propeller size. Below is a breakdown of the most common FPV categories:

1. Micro FPV (Tiny Whoop: 1″–3″, 65–85 mm)

   • Typical Use: Indoor flying, entry-level practice, tiny whoop leagues.

   • Motors: 1102–1106 or 1306 brushless (mounted inside protective ducts).

   • Prop Size: 40 mm–55 mm.

   • Weight (All-Up): 60–80 g (including battery).

   • Recommended LiPo: 1S–2S, 300–650 mAh, 45C–80C.

   • Flight Time: ~2–4 minutes hover; ~1.5–2 minutes aggressive.

2. Sub-250 g / Micro-Light (2.5″–3.5″, 100–200 mm)

   • Typical Use: Outdoor park flying, under-250 g regulations, beginner freestyle.

   • Motors: 1105–1407 (1105 for lighter, 1407 for more thrust).

   • Prop Size: 65 mm (2.5″) or 75 mm (3″).

   • Weight (All-Up): 230–250 g (including battery).

   • Recommended LiPo: 3S–4S, 650–1,000 mAh, 60C–100C.

   • Flight Time: ~3–5 minutes mixed throttle; ~5–6 minutes gentle hover.

3. Standard/Freestyle (5″, 180–220 mm)

   • Typical Use: Outdoor freestyle, skatepark sessions, backyard acro.

   • Motors: 2206–2306 (2,300 KV–2,600 KV on 4S; 1,800 KV–2,000 KV on 6S).

   • Prop Size: 125 mm (5″).

   • Weight (All-Up): 850–1,000 g (including battery).

   • Recommended LiPo:

     • 4S: 1,300–1,800 mAh, 75C–100C.

     • 6S: 1,000–1,300 mAh, 100C–120C (for racers or aggressive flyers).

   • Flight Time:

     • 4S 1,500 mAh: ~4 minutes aggressive; ~5 minutes hover.

     • 6S 1,200 mAh: ~3 minutes aggressive; ~4 minutes hover (with more thrust).

4. Cinewhoop / Hybrid (3″–4″ cine frames)

   • Typical Use: Cinematic indoor/outdoor video, safe proximity flying.

   • Motors: 1105–1407 (3″) or 1407–1806 (4″), with low-pitch props.

   • Prop Size: 75 mm–100 mm (ducted).

   • Weight (All-Up): 300–500 g (including camera + ducts).

   • Recommended LiPo: 4S–6S, 2,200–3,000 mAh, 65C–100C.

   • Flight Time:

     • 4S 2,500 mAh: ~7 minutes hover (with ~300 g camera).

     • 6S 2,200 mAh: ~6 minutes hover at ~70% throttle (with ~300 g camera).

5. Long-Range / Endurance (6″–7″, 220–315 mm)

   • Typical Use: Aerial mapping, surveying, search & rescue, extended-range photography.

   • Motors: 2208–2812, low KV (800–1,200 KV).

   • Prop Size: 150 mm–175 mm (6″–7″).

   • Weight (All-Up): 1,200–2,000 g (depending on payload).

   • Recommended LiPo: 6S–8S, 3,000–6,000 mAh, 30C–45C.

   • Flight Time:

     • 6S 4,000 mAh: ~15–20 minutes cruise at 50–60% throttle.

     • 6S 6,000 mAh: ~20–25 minutes cruise.

     • 8S 3,500 mAh: ~18–22 minutes cruise (thanks to higher voltage, lower current draw).

Frame-to-Wheelbase Reference (approximate):
• 1″–2″ (25–50 mm) → Tiny Whoop
• 2.5″–3″ (65–85 mm) → Sub-250 g micro
• 5″ (125 mm) → Standard freestyle
• 6″ (150 mm) → Long-range efficiency
• 7″ (175 mm) → Heavy-lift / mapping

---

LiPo Battery Fundamentals

1. Voltage & “S-Count”

A LiPo pack’s “S” rating equals the number of cells wired in series. Each LiPo cell has a nominal voltage of ~3.7 V (4.2 V fully charged, ~3.3 V under load). Therefore:

• 1S: 3.7 V nominal (4.2 V full)

• 2S: 7.4 V nominal (8.4 V full)

• 3S: 11.1 V nominal (12.6 V full)

• 4S: 14.8 V nominal (16.8 V full)

• 5S: 18.5 V nominal (21.0 V full)

• 6S: 22.2 V nominal (25.2 V full)

• 7S: 25.9 V nominal (29.4 V full)

• 8S: 29.6 V nominal (33.6 V full)

Most FPV pilots choose 4S (the “sweet spot”) for 5″ freestyle, 6S for high-volt racing or long-range, and 6S–8S for extreme endurance or heavy-lift tasks.

2. Capacity (mAh) & Flight Time

Capacity is measured in milliamp-hours (mAh). Roughly:

Flight Time (minutes) ≈ (Capacity ÷ Average Current Draw) × 60 × 0.80 (80% usable)

For example, a 1,500 mAh LiPo drawing 60 A average → 1.5 Ah ÷ 60 A = 0.025 hours = 1.5 minutes × 0.8 = ~1.2 minutes at full throttle. In real-world mixed-throttle flying, expect ~4 minutes from a 1,500 mAh 4S at a 60 A average draw.

• High-Capacity Packs (≥ 2,200 mAh): Common for cinewhoops or endurance builds, but they weigh more.

• Lower-Capacity, High-C Packs (1,000–1,500 mAh, 75C–120C): Standard for freestyle and racing, where rapid discharge matters more than raw capacity.

3. C-Rating & Discharge Curve

C-rating indicates the maximum continuous discharge current relative to capacity. For example, a 2,000 mAh LiPo at 100 C can theoretically deliver 200 A continuously (2 Ah × 100 C = 200 A). In practice, internal resistance and voltage sag limit usable current, but a higher C-rating still means less sag under load.

• Caída de tensión: Under heavy draw, a 1,500 mAh 75 C pack might sag to 3.3 V/cell at a 50 A draw, whereas a 1,500 mAh 100 C pack under the same load might only drop to ~3.6 V/cell—preserving throttle response.

• Burst C-Rating: Some packs list a burst rating (e.g., 100C/200C), allowing short, high-current peaks. Sustained continuous rating is more important for temperature management.

4. Energy Density & Weight Trade-Offs

LiPo energy density typically falls around 200–220 Wh/kg (depending on pouch packaging). As an example, an 1,800 mAh 4S LiPo (14.8 V nominal) stores ~26.64 Wh and weighs ~200 g. Thus:

26.64 Wh ÷ 0.2 kg = ~133 Wh/kg (pack basis)

A 2,200 mAh 4S (32.56 Wh, ~240 g) yields ~135 Wh/kg.

• Heavier, Higher-Capacity Packs: Longer flight but reduced agility.

• Lighter, Lower-Capacity Packs: High thrust-to-weight ratio but shorter runtime.

Every pilot must find the sweet spot: enough amp-hours for the flight style without overweighting the frame.

---

Matching LiPo Batteries to FPV Drone Types

Below is a detailed guide for each FPV category—matching frame, motor needs, and flight style with LiPo pack voltage, capacity, and C-rating.

1. Micro FPV (Tiny Whoop: 1″–3″, 65–85 mm)

• Use Case: Indoor practice, tiny whoop racing, exploration of small spaces.

• Recommended LiPo:

  • 1S 300–450 mAh, 45C–80C

  • 2S 300–650 mAh, 45C–75C (for slightly more thrust on brushless whoop motors)

• Flight Time: ~2–4 minutes hover; ~1.5–2 minutes aggressive.

• Typical Draw: 8–12 A hover; 15–20 A peak.

• Why These Specs: Tiny Whoop motors cannot sustain very high current—too much C-rating simply adds weight for little benefit. A 2S 450 mAh 65C provides ~29 A (0.45 Ah × 65 C = 29 A), yielding about 3 minutes of moderate throttle flight.

Example Calculation:
A 2S 450 mAh 65C pack (~20 g) powering a 1106 6000 KV motor:

• Hover draw ~10 A → 0.45 Ah ÷ 10 A = 0.045 h = 2.7 minutes × 0.8 ≈ 2.2 minutes.

• Aggressive bursts up to 20 A reduce runtime to ~1.5 minutes.

2. Sub-250 g / Micro-Light (2.5″–3.5″, 100–200 mm)

• Use Case: Outdoor park flying, under-250 g compliance, beginner freestyle.

• Recommended LiPo:

  • 3S 650–850 mAh, 60C–100C

  • 4S 650–1,000 mAh, 75C–100C

• Flight Time: ~3–5 minutes mixed throttle; ~5–6 minutes gentle hover.

• Typical Draw: 20–30 A hover; 40–60 A peak.

• Why These Specs: A 3S 850 mAh 75C pack (~45 g) can deliver ~63 A continuous (0.85 Ah × 75 C = 63 A). Pilots often choose 4S on 3″ frames for snappier throttle: a 4S 850 mAh 100C (~55 g) can supply ~85 A.

Example Calculation:
3″ sub-250 g quad with 1105 3600 KV motors:

• 3S 850 mAh 75C LiPo: Hover ~20 A → 0.85 Ah ÷ 20 A = 0.042 h = 2.5 minutes × 0.8 ≈ 2 minutes of mixed-throttle flight; ~3 minutes gentle.

• 4S 850 mAh 100C: Hover ~18 A → 0.85 Ah ÷ 18 A ≈ 0.047 h = 2.8 minutes; more thrust when needed (peak ~60 A).

3. Standard/Freestyle (5″, 180–220 mm)

• Use Case: Outdoor freestyle, skatepark sessions, general hobby flying.

• Recommended LiPo:

  • 4S 1,300–1,800 mAh, 75C–100C (most common)

  • 6S 1,000–1,300 mAh, 100C–120C (for sharper throttle response)

• Flight Time:

  • 4S 1,500 mAh 75C (≈180 g): ~4 minutes aggressive; ~5 minutes hover.

  • 6S 1,200 mAh 100C (≈160 g): ~3 minutes aggressive; ~4 minutes hover with 10–12% more thrust.

• Typical Draw: 60–70 A hover (4S) or 50–60 A (6S); 100–140 A peaks during acro.

• Why These Specs: A 4S 1,500 mAh 100C pack supplies 150 A max (1.5 Ah × 100 C = 150 A). Under an average 60 A draw, 1.5 Ah ÷ 60 A = 0.025 h = 1.5 minutes × 0.8 = 1.2 minutes at sustained full throttle—balanced by occasional hover segments. That equates to ~4 minutes of mixed flight.

Freestyle vs. Racing Considerations:

• Freestyle Pilots often favor 4S 1,800 mAh because its 14.8 V output gives smoother throttle transitions and the extra capacity yields a few more seconds mid-air.

• Racers/Aggressive Flyers often choose 6S 1,200 mAh 100C because 22.2 V allows similar power at lower current (~60 A instead of ~90 A), reducing heat on ESCs/motors and generating sharper throttle response.

4. Cinewhoop / Hybrid (3″–4″ Cine Frames)

• Use Case: Cinematic indoor/outdoor video, safe close-quarters flight.

• Recommended LiPo:

  • 4S 2,200–3,000 mAh, 65C–100C (for GoPro Session or similar)

  • 6S 2,200–3,000 mAh, 65C–100C (for longer runs with heavier camera gear)

• Flight Time:

  • 4S 2,500 mAh 75C (≈240 g): ~7 minutes hover (with ~300 g camera).

  • 6S 2,200 mAh 75C (≈220 g): ~6 minutes hover at ~70% throttle (with ~300 g camera).

• Typical Draw: 15–25 A hover; 35–45 A peaks during minor corrections.

• Why These Specs: Cinewhoops carry extra mass (gimbal, GoPro, LEDs). A 4S 2,500 mAh pack can supply 187.5 A max (2.5 Ah × 75 C). Under a 20 A hover draw: 2.5 Ah ÷ 20 A = 0.125 h = 7.5 minutes × 0.8 ≈ 6 minutes of real flight. Using 6S 2,200 mAh at 22.2 V yields 165 A max (2.2 Ah × 75 C). That same 20 A hover draw yields 0.11 h = 6.6 minutes × 0.8 ≈ 5 minutes—enough for most cinematic runs.

• Voltage Stability: Cinewhoops need consistent voltage under load to avoid jello in footage. A slightly higher C-rating (e.g., 100C) minimizes sag when tilting or yawing with added drag from the camera.

5. Long-Range / Endurance (6″–7″, 220–315 mm)

• Use Case: Aerial mapping, surveying, search & rescue, extended-range photography.

• Recommended LiPo:

  • 6S 3,000–6,000 mAh, 30C–45C

  • 8S 3,000–5,000 mAh, 30C–45C (optimizing voltage over current draw)

• Flight Time:

  • 6S 4,000 mAh 35C (≈380 g): ~15–20 minutes cruise at 50–60% throttle.

  • 6S 6,000 mAh 30C (≈500 g): ~20–25 minutes cruise.

  • 8S 3,500 mAh 40C (≈400 g): ~18–22 minutes cruise (due to higher voltage, lower current).

• Typical Draw: 20–30 A cruise; 40–60 A peaks climbing.

• Why These Specs: Long-range frames emphasize efficiency over brute power. Low-KV motors (800–1,200 KV) spinning large 6″–7″ props at moderate RPM generate lift with relatively low current draw (~20–30 A). For instance, a 4 Ah pack at 25 A cruise → 4 Ah ÷ 25 A = 0.16 h = 9.6 minutes × 0.8 ≈ 7.7 minutes of stable flight. Because long-range rigs frequently operate at 40–50% throttle, actual flight times often edge toward 15–20 minutes.

• 8S vs. 6S Considerations: An 8S pack (29.6 V nominal) delivering 600 W requires only ~20 A (29.6 V × 20 A = 592 W), whereas a 6S pack delivering 600 W needs ~27 A (22.2 V × 27 A ≈ 600 W). Lower current reduces ESC/motor heat and slightly improves endurance—though 8S packs tend to be more expensive and harder to source at very high mAh ratings.

---

Key Selection Considerations

1. Thrust-to-Weight (T/W) vs. Flight Time

Thrust-to-Weight Ratio = (Total Motor Thrust at Full Throttle) ÷ (All-Up Drone Weight).

• Acro/Racing Quads often aim for T/W ≥ 5:1. For a 1,000 g drone to be fully nimble, it needs ≥ 5,000 g of thrust total.

• Ejemplo: A 5″ freestyle quad on a 6S 1,200 mAh pack (AUW 950 g) generating ~1,300 g per motor → total thrust ~5,200 g → T/W ≈ 5.5:1.

• Ejemplo: The same quad on a 4S 1,800 mAh pack (AUW 900 g) generating ~1,200 g per motor → total ~4,800 g → T/W ≈ 4,800/900 ≈ 5.3:1.

Trade-Off: Heavier batteries (higher mAh) reduce T/W but extend flight. Lighter, lower-mAh packs boost agility at the cost of runtime. Choose based on preferred flight style: sustained freestyle vs. extended mapping.

2. Voltage Sag & C-Rating

Under high current draw, LiPo voltage sags—dropping effective voltage at the motor. A higher C-rating reduces sag.

• Example Data:

  • 4S 1,500 mAh 50C: Under a 50 A draw → nominal 14.8 V, sag to ~12.8 V (3.2 V/cell).

  • 4S 1,500 mAh 100C: Under the same 50 A → sag to ~14.0 V (3.5 V/cell).

Recommendation:

• Use ≥ 75C for sub-250 g builds.

• Use ≥ 100C for 5″ freestyle/racing.

• Use 30C–45C for long-range packs (because these rigs draw lower current overall, making extremely high-C unnecessary).

3. Battery Weight & Center-of-Gravity (CG) Effects

Every extra gram shifts CG, affecting flight characteristics—especially roll and pitch responsiveness.

• Ejemplo: A 4S 1,800 mAh pack (~200 g) vs. a 4S 2,200 mAh (~240 g) will make the front heavier if mounted under the flight controller. To compensate, you might move the camera forward or adjust blade tilt.

• Tip: Position the LiPo as close as possible to the FC’s center-of-mass or slightly rearward to match camera offset—ensuring neutral pitch/roll control.

---

Real-World Case Studies

Case Study A: 5″ Freestyle Build (4S 1,800 mAh vs. 6S 1,200 mAh)

Quad Details:

• Frame: 5″, 2206 2,300 KV motors, 5″ tri-blade props.

• AUW w/4S: ~900 g; AUW w/6S: ~950 g.

4S 1,800 mAh 75C LiPo:

• Max Current: 1.8 Ah × 75 C = 135 A.

• Average Draw: ~70 A (mixed freestyle).

• Voltage Under Load: ~13.0 V (3.25 V/cell).

• Flight Time:

  • 1.8 Ah ÷ 70 A ≈ 0.0257 h = 1.54 minutes at sustained high throttle × 0.8 ≈ 1.23 minutes.

  • Mixed-throttle: ~4 minutes.

• Thrust: Each motor ~1,200 g thrust → total ~4,800 g → T/W ≈ 4,800/900 ≈ 5.3:1.

6S 1,200 mAh 100C LiPo:

• Max Current: 1.2 Ah × 100 C = 120 A.

• Average Draw: ~65 A (medium-aggressive flying).

• Voltage Under Load: ~21.6 V → ~20.7 V (3.45 V/cell).

• Flight Time:

  • 1.2 Ah ÷ 65 A ≈ 0.0185 h = 1.11 minutes at sustained high throttle × 0.8 ≈ 0.9 minutes.

  • Mixed-throttle: ~3 minutes.

• Thrust: Each motor ~1,350 g thrust → total ~5,400 g → T/W ≈ 5,400/950 ≈ 5.7:1.

Conclusión:

• 4S 1,800 mAh: ~4 minutes mixed flight, smoother throttle, slightly longer runtime—ideal for casual freestyle sessions.

• 6S 1,200 mAh: ~3 minutes mixed flight, ~12% more thrust, more responsive, cooler ESC/motors during bursts—better for racing or highly aggressive acro.

---

Case Study B: Long-Range 7″ Build (6S 6,000 mAh vs. 8S 3,500 mAh)

Quad Details:

• Frame: 7″, 2812 1,000 KV motors, AUW w/6S = ~1,700 g; AUW w/8S = ~1,600 g (slightly lighter pack).

6S 6,000 mAh 30C LiPo:

• Max Current: 6 Ah × 30 C = 180 A.

• Average Cruise Draw: ~25 A at 50% throttle (22.2 V).

• Voltage Under Load: ~21.6 V → ~21.1 V (3.52 V/cell).

• Flight Time:

  • 6 Ah ÷ 25 A = 0.24 h = 14.4 minutes × 0.8 ≈ 11.5 minutes of steady cruise.

  • In practice: ~13–15 minutes (due to occasional low-throttle glides).

• Thrust: Each motor ~1,200 g at 50% throttle → total ~4,800 g → T/W ≈ 4,800/1,700 ≈ 2.82:1.

8S 3,500 mAh 40C LiPo:

• Max Current: 3.5 Ah × 40 C = 140 A.

• Average Cruise Draw: ~18 A at 50% throttle (29.6 V).

• Voltage Under Load: ~29.6 V → ~28.5 V (3.56 V/cell).

• Flight Time:

  • 3.5 Ah ÷ 18 A = 0.194 h = 11.6 minutes × 0.8 ≈ 9.3 minutes of steady cruise.

  • In practice: ~10–12 minutes (with occasional throttle dips).

• Thrust: Each motor ~1,250 g at 50% throttle → total ~5,000 g → T/W ≈ 5,000/1,600 ≈ 3.13:1.

Conclusión:

• 6S 6,000 mAh: ~13–15 minutes real-world flight, lower pack cost per Wh, slightly less agility.

• 8S 3,500 mAh: ~10–12 minutes flight, ~10% more thrust for the same power, more responsive throttle, cooler ESCs at cruise.

---

Battery Maintenance & Safety Best Practices

LiPo batteries deliver outstanding power density, but they require careful handling to remain safe and reliable.

1. Proper Charging & Storage

• Utiliza un cargador de equilibrio específico: Always charge LiPos at 1 C (e.g., a 1,500 mAh pack at 1.5 A max) unless the manufacturer explicitly allows faster charging. Charging at ≥ 2 C generates excessive heat and reduces cycle life.

• Balance Mode: Ensure each cell is balanced to within ±0.02 V. Unbalanced cells risk overcharge or over-discharge on individual cells.

• Tensión de almacenamiento: If not flying within 24 hours, store LiPo at ~3.8 V per cell (≈50% charge) to reduce internal stress and prolong lifespan by ~30% compared to full-charge storage.

• Temperatura: Charge and store at room temperature (20–25 °C). Avoid charging below 0 °C (risk of plating) or above 40 °C (accelerates chemical degradation).

• Seguridad contra incendios: Charge on a fireproof surface or within an approved LiPo bag. Never leave a charging pack unattended.

2. Visual Inspection & Handling

• Puffiness: A swollen pack indicates internal gas buildup—dispose of it properly.

• Connector Integrity: Inspect XT30/XT60/XT90 or Molex connectors and solder joints for discoloration, melting, or fraying wires—signs of excessive heat or high resistance.

• Voltage Checks: Use an on-screen display (OSD) or a handheld LiPo checker to monitor each cell’s voltage under load. Avoid flying if any cell sags below 3.3 V under no load (3.0 V under load).

• Evite los daños físicos: Store packs in a rigid container. Avoid dropping, puncturing, or puncturing the pouch.

3. Safe Discharge & Landing Protocols

• Low-Voltage Cutoff (LVC): Program your flight controller or ESC to cut off at around 3.3 V per cell under no load (3.0 V under load). For a 4S pack, that translates to ~13.2 V no-load.

• Landing Strategy: If you notice voltage sag approaching LVC under hover, shift to gentle forward flight to maintain lift while allowing voltage to recover slightly.

• Prevent Over-Discharge: Never let any cell drop below 3.0 V under load (3.2 V at rest). Over-discharged LiPo packs risk irreversible cell damage and can swell or become unstable.

4. Temperature Management

• Ambient Effects: LiPos lose ~20% capacity below 0 °C. In cold climates, warm batteries to ~10 °C before flying.

• Monitor Cell Temperature: If possible, use an OSD or external temperature sensor to watch cell temps. Avoid flying if pack temperature exceeds 50 °C, as prolonged heat accelerates aging and increases the risk of failure.

5. Disposal & Recycling

• Safe Discharge: Use a specialized LiPo discharger or a resistive load (an incandescent bulb) to fully discharge packs to ~3.0 V per cell.

• Saltwater Bath: Submerge the fully discharged pack in a saltwater solution (1 cup table salt per 4 L water) for 24–48 hours to neutralize remaining charge.

• Recycling Centers: Once inert, wrap terminals in tape and drop off at an e-waste or battery recycling facility. Never throw LiPo packs in the regular trash.

---

Introducing Our New 21700 Battery Pack Solution