Denis Loo

Size: px

Start display at page:

Download "Denis Loo"

Conrad Mitchell
5 years ago
Views:

1 Electric Systems Configuration Denis Loo Version

2 Motivation or Why Bother??? Clean and Quiet Indoor Flying Suited for smaller Aircraft & Heli s Electric Only Kits/ARFs FPV, Suitable for data logging Motor Gliders (Restarting/Stowing) Multi Rotor Applications Lower cost with smaller sizes Many Brands & Mfg of components available (Lots of choices and options) Convenience Reduced Maintenance Required Finishes need not be Fuel Proof Mass Stability Performance Stability ActivePropBraking Possible No more Dead Sticks Less Vibration Conversion kit availability 2

3 Constraints Flight Time 15 min (Shorter) Charging Time & Care Battery Life, Performance and Cost Environmental Temperature & Moisture Control and Propulsion Power Battery Access & Cooling Cost Trade Offs (Generators, Car Battery) Safety 3

4 Motor Components Battery, Capacitors Connectors, Spark Arresting EMI, CE (Electrical Noise) & Filters/Shielding Switches, Arming SafetySwitches Switches, Alarms Electronic Speed Control (ESC) Battery Elimination Circuit (BEC) or A123 E Props 4

5 Basic Knowledge 1 Horsepower (HP) = Watts (W) 1 Kilowatt (kw) = 1000 W Voltage (V) Volts (V) Current (I) Amperes (A) Resistance (R) Ohms (Ω) Voltage (V) = Current x Resistance (V=I*R) Ohm s Law Power (P) = Current x Voltage (P=I*V or I 2 *R) Battery Capacity (β) = Current x Time (β=i*t) = 1A*h 1000 mah 5

6 Basis & Interpretation Force (N) = Mass (kg) x Acceleration (m/s 2 ) = kg*m/s 2 Work (J) = Force (N) x Distance (m) = N*m or Energy Power (W) = Work (J)/ Time (s)= N*m/s or Rate of Work Thus: 1 Watt (W) = Force of 1 N over a Distance of 1 m for 1 s 1 Joule (J) = 1 W for 1 s duration Volt (V) = Energy / Unit Charge Ampere (A) = Rate of flow Ohm (Ω) = Resistance to flow Coulomb (C) = Unit Charge = Charge carried by 1 Afor 1 s charge of approx x electrons (lots!) 6

7 How Much Power? Power Loading Watt ts / lb Slow Flyer or Park Flyer Trainer or Slow Flying Scale Sport Aerobatic & Fast Flying Scale Advanced Aerobatic & High Speed Lightly Loaded 3D & Ducted Fans Unlimited performance aerobatic & 3D 7

8 Glow Engine Output (HP) Output Power vs Displacement 25 Output (HP) Peak Power Stroke 4 Stroke Displacement (in 3 ) 8

9 Peak Power Output (kw) Glow Engine Output (kw) Output Power vs Displacement 2 Stroke 4 Stroke Displacement (in 3 ) 9

10 Engine Size and Output (HP) Pe eak Powe er Outpu (HP) Output Power vs Displacement 2 StrokeGlow (O.S. EngineData) Displacement (in 3 ) 10

11 Engine Size and Output (W) Pe eak Power Output (W) Output Power vs Displacement 2 Stroke Glow Displacement (in 3 ) 11

12 Motor Selection Type (Brush, Rotor) Size & Weight Battery Configuration i (S) > Voltage Range Motor Constant (Kv = 1000 s RPM/volt) Current Rating (Sustained & Transient) Cooling Requirements Mechanical (Shaft, Mounting, Prop Adapter) 12

Resistance : 76 mω I NO LOAD @ 7V: 1.19A Dimensions: 35mm X 30mm / 1.38in X 1.18in Shaft Ø: 4mm / 0.

13 Motor Example Mfg: TURNIGY AerodriveXp Type: Brushless, Outrunner Model: TR35 30 B Input Voltage: 7.4V~11.1V (2~3S Li Po) KV: 1400 rpm/v within 10% # of turns: 22 Delta I MAX : 10~15A I CAP : 22A/60s Internal Resistance : 76 mω I NO 7V: 1.19A Dimensions: 35mm X 30mm / 1.38in X 1.18in Shaft Ø: 4mm / 0.16in Weight: 77g / 2.72oz # of poles/magnets: 14 Recommended Model Weight : 600~1300g / 21~45oz Power Equivalence :.12, 2 stroke 13

14 ESC Selection Type (Brushless/Brushed/Application) Current Rating (Amps) BEC Rating, Mode PWM Speed, Timing Programming Method and Options (many) Size & Weight Cooling Needs Electrical Noise and Shielding Connectors 14

15 ESC Selection (Typical) I CONST : 30A I BURST : 40A BEC Mode:Linear BEC: 5V / 2A Li Po Cells: 2 4 NiMH :5 12 Weight: 25g Size: 45x24x11mm User Programmable, both via controller & optional programming card. UBEC Simplicity is the key to reliability! 15

16 Safety Accessories Voltage Protectors Battery Alarms Arming Safety Switches Voltmeters Jeti Anti-Spark 16

17 Accessories ESC Programming Card USB Programming Adaptor Li-Po Charger Watt Meters Charging Bags Li-Po Cell Checker 17

18 Battery Options (for R/C) Type Pros Cons Alkaline Ni Cd NiMH Li Po Li FePO4 (A123) Convenient, Availability Safe, Reliable, Disposable Can be cheaper than other rechargeable types Durable, Safe Faster recharge Better Life Cycle Than Ni Cd Fewer Memory issues Higher capacity Availability, Light Weight, Popular Fast charging, Efficient Packaging High Capacity, (3.6V/cell) Charge remaining easily measured Non Rechargeable, Costly Heavier, Memory, Limited Performance Outgassing, Disposal Issues (Cadmium) Lower voltage than alkaline Heavier than Li types Lower voltage than alkaline Special Charger, Need for Balancing Voltage varies with charge, Need BEC Somewhat fragile, can be more costly Fire hazard if abused, limited cycle life g g y, y Safety and durability of Ni Cd Lighter weight than NiMH Flat Discharge (3.3v/cell) Can eliminate BEC High Current a123.htm Limited selection, more expensive Special Charger, cylindrical cells Charge Remaining harder to measure ( t) Voltage Sag A little heavier than Li Po 18

19 Li Po Battery Selection Configuration: (S) = # of cells in Series Voltage (V) & Speed (P) = # of cells in Parallel Current (I) & Torque (C) = Max Continuous Discharge Max Current (I) & Peak Torque mah = Capacity & Run Time Example: 20C, 3S2P 2100 mah Battery: = 3 Cell Battery = 3.7 V/cell nominal x 3 = 11.1 V = 2 Cells in parallel = 3 x 2 = 6 Cells in pack = 2100/1000 A x 20 C x 2 P = 84A Peak Current =1C* 2100/1000 = 2.1A Max Charge Current 19

20 Battery Example Type: Lithium Polymer Capacity: 1800 mah Connector Type: EC2 Balancing Connector: Std 4-Pin Wire Gauge: 13 # of cells: 3 Weight: 4.0 oz (114g) Configuration: 3S Voltage (nominal): 11.1v Length: 4.05 in (103mm) Width: 1.35 in (34.5mm) Height: 0.55 in (14mm) Max Continuous Discharge: 20C Max Continuous Current: 36A 20

21 General Guidelines: Battery Selection Up to 50W 1s-2s Park and Indoor Flyers Up to 100W 2s-3s Park Flyers 100W-500W 3s 5lb AUW 500W-800W 4s 0.40 to 0.46 Glow Engine 800W-1000W 5s 900W-1500W 6s 0.60 to 0.90 Glow Engine More 8s-10s Specialized Large Models 21

22 Li Po Battery Safety Min Voltage per cell: 3.0 Min ESC Voltage Cutout: 3.0 (Hard), 3.3 (Soft) Max Charge: 1C (i.e mah 1.8A) Lower is better Max Draw (I MAX ): Rated on battery (i.e. 30C = 1.8*30= 54A 50 60% of Capacity (i.e. Nominal Voltage) Always connect battery last or use an arming switch Check and discard (discharge first) if mechanically upset Charge in a monitored Non-Flammable Area with approved charger Check and balance charge as required Store in non-flammable Container (i.e. Battery Safety Bag) Overheating occurs with excessive current drain or overcharging Puffing (Ballooning) may occur if overheated (capacity degraded) Battery life is finite, Capacity and I MAX will degrade with # of cycles 22

23 Li Po Charging Importance of balancing 23

24 Li Po Voltage and % Capacity Remaining 24

25 Battery Energy Power = I * V P = A * v (Watts) Energy = Power * Time E = W * t (Joules) Capacity of a battery β in units of ma*hr For an 3S (11.1V), 1800 mah battery: Power (for 1 hr) = 1800 / 1000 x = 20 W for 1 hr Energy Content = 3.6 *1800 * 11.1 = J Note: Battery Capacity is degraded with frequency of excursions to I MAX! 25

26 Battery Output But limited by battery temp, I MAX and wire sizes! 26

27 Battery Life vs Output Demand 80 Curren nt (A) Outout mah 1800 mah Time (Min) 27

28 Battery Mass Mass (g) Battery Li-Po Battery Mass vs Cell Capacity y = x y = x y = x C 10-15C15C 15-20C Cell Capacity (mah) 28

29 Battery Energy Density 6000 Li-Po Cell Capacity vs Volume Capac city (ma Ah) % y = x % y = x y = x C 10-15C 15-20C Cell Volume (cm 3 ) 29

30 Battery Density ght (g) Wei Li-Po Cell Weight vs Volume (Density) 5-10C 10-15C y = x C 6% Premium y = x y = x % Premium Volume (cm 3 ) 30

31 Wire Silicone Noodle Type Popular Flexible, Hi Temp and Current Rating, Low Ω Plating to be suited to soldering (Sn, Si) Restrain to prevent fatigue due to wire movement Wire Gage vs Current Carrying Capacity 31

32 Connectors Polarization or Keying (non Reversible) Standards for convenience, Availability Insulation and security, Ease of installation Current trti Rating (Amps) and Wire Gage Deans popular but short circuit risk Practice Soldering Skills for good joints Use Heat shrink to prevent shorts! Anti Spark connectors can minimize arcing Arming Switches Recommended d 32

33 Popular Connectors EC Type JST Deans style Bullet Type XT60 HXT 33

34 Soldering Stuff Soldering Iron (With Cleaning Pad) Solder Flux Solder Removal Tools Soldering Jigs IPA Vise Wire Strippers Heat Gun 34

35 Soldering Tips Cleanliness is key Wattage of Iron and Temperature critical! Thermocouple Type Iron Faster and Stable Tip Temperature 60Sn/40Pb solder with Rosin Flux core is optimal for electronics Use suitable flux generously but avoid inhaling flux vapors Stronger solders available (not for electronics) but generally harder to use & more toxic! Avoid mixing soldering iron tips with Solder/Flux types Clean and Tin tip of soldering iron often Pre Tin components to be soldered Heat part with Iron Tip, apply solder to Part Clean completed Joint with IPA (l (Flux is corrosive) 35

Soldering Tips Lots of online Resources: http://www.talkingelectronics.com/projects/5-projects/projects13.html http://homediyelectronics.

36 Soldering Tips Lots of online Resources: htm 36

37 Calculator Tools Many available, Some Free: Di Drive Cl Calculator: l d / ecalc: FlyDMA: RC Groups Compilation: ETC 37

38 Plane: Configuration Example Ultra Stick 25E ARF Mfg Config: Baseline Option X Motor: Power 25 Power 25 Battery / mah 3S2P / S2P / 4000 ESC 40A with BEC 40A with BEC Prop 12 x 6E 11 x 5E What would be the estimated performance benefit of a 4S battery if we want to keep the same 40A ESC? Can manually calculate, test or use online tools 38

39 Online Software (ecalc) Baseline 39

40 Online Software (ecalc) 4S Case 40

41 Online Software (ecalc) Plots 3S Battery Baseline : 3S2P, 4000 mah Power x 6E New 4S Battery : 4S2P, 4000 mah Power x 5E 41

42 Example Result Summary Flight Time: 9% Aircraft / Prop Speed: 15% Battery Weight: 33% Overall llaircraft Wih Weight: 14% Power Output (Max): 50% Peak Current: 10% Power/Weight Ratio: 28% Thrust/Weight Ratio: 3% 4S2P + 11x5E vs 3S2P + 12x6E 42

43 Bench Testing is Recommended! 43

44 Data: 2S 20C 7x5E APC 44

45 Data: 3S 35C 7x5E APC 45

46 Data: 2S 20C 8x4E APC 46

47 Data: 3S 35C 8x4E APC 47

48 Test Data in in amps Volts Watts Cells Rating mah KPH Mfg Type D P Imax Vmin Speed Pmax S C Capacity Speed APC SF APC SF APC SF APC E MA APC E MA APC E APC E APC SF APC SF APC SF APC E MA APC E MA APC E APC E

49 Questions? Thank you for your interest! 49

Electric Motors And Batteries. Flightline Hobby, October 2018

Electric Motors And Batteries. Flightline Hobby, October 2018 Electric Motors And Batteries Flightline Hobby, October 2018 This Year s Theme: Old vs New Brushed vs Brushless Rubber vs Electric NiMH vs LiPO Brushed Motor Physics Brushed: Magnetic fields switched mechanically.