Ideas on Building a Reliable BL System by ReddyWatts.

[ReddyWatts]

Steps for building a Fast Electric

1. Build a boat stand.
2. Drill and mount the strut and rudder. Might need to strengthen the transom.
3. Drill holes for water-cooling inlet and outlet.
4. Install radio antenna.
5. Install water jacket and thrust bearing on motor.
6. Place all equipment in boat to find the desired center of gravity. Move the motor around, so that you after you mount the motor, you will still be able to move the batteries and keep the COG in the desired range. 27-33%
7. Epoxy motor mount to hull. Might need to strengthen the inside bottom of hull.
8. Decide where to cut hole/slot for flex drive tube.
9. Decide where to drill hole for rudder/servo connecting rod.
10. Bend, then cut tubing to fit between strut and motor. Leave less than ½ inch gap between motor coupler and tube. Start with strut bottom 1/8 above the bottom of hull. Raise it during water tests to desired height. Use heat shrink on strut connection.
11. Cut flex cable to length needed.
12. Install flex cable and check alignment at motor and strut. One sweeping bend is better. Epoxy tube into hull.
13. Remove all parts.
14. Paint the hull.
15. Add floatation to hull and hatch.
16. Reinstall all parts and seal.
17. Mount servo and use rubber boot to waterproof connecting rod and hole.
18. Lubricate drive line.
19. Install radio and battery switch if used.
20. Install battery tie downs.
21. Install water-cooling hoses. Use cable ties on all connections. pressure test for leaks.
22. Test hull in bath tub for water leaks.
23. Program and test ESC.
24. Check motor rotation.
25. Check for receiver glitching.
26. Check everything for tightness, use blue thread lock on all threads.
27. Use tape to seal the hatch.

[ReddyWatts]

FE setups "Big Picture"

I hope by showing a structure of setups you will see the "Big Picture" for a better understanding of Fast Electrics.

There are to many variables for this data to fit all the different hull and motor loads. Many setups will fall outside this general information guideline.

FE SETUPS

--hull size /--------Cells---------/ ----Motor Kv----- / -------Prop Size------/---Type ESC---/-BEC-/ESC Amp Rating

17”- 24” / 2s LiPo or 6 cell NiMh / 5500 -3200Kv / 30mm - 40mm Diam. / Low Voltage / Avail. / 120 amp

20"-27" / 3s LiPo or 8 cell NiMh / 3500-2500kv / 35mm – 42mm Diam. / Low Voltage / Avail. / 120 amp

24”-29” / 4s LiPo or 12 cell NiMh /2650-1600Kv /37mm - 46mm Diam. / Low Voltage / Avail~Disc / 120-240 amp

26”-32" / 6s LiPo or 18 cell NiMh /1800-1100Kv /40mm - 52mm Diam. / Low or High / Disc. / 120-180-240 amp

30"- 36" / 8s LiPo or 24 cell NiMh / 1350-800Kv /45mm – 55mm Diam. / High Voltage / N/A / 180-240 amp

34" - 42" / 10s LiPo or 30 cell NiMh / 1100-600Kv /47mm + Diameter / High Voltage / N/A / 180-240 amp

38" - 46" / 12s LiPo or 36 cell NiMh / 900-550Kv / 50mm + Diameter / High Voltage / N/A / 240 amp

Always start testing with a small prop and work up to your desired amp readings!


HULL SIZE AND OSE MOTORS

This is a general guideline for the motors OSE sells. I know it is hard for this to cover all selections, since FE setups can be complex and extend over a wide range of extremes. Remember this is more for conservative setups to help new guys get started.

hull size…..... /…...... Neu….... /….. Feigao.540…../Feigao 580/...700SC../.SV27./.Proboat./..Ammo../.380.

<<"-20"....../.....1506........../.......Fiegao.S......./................./................./......../............../.............../.380 L

17”-24”…../….. 1506,1509./…..Feigao S-L…...../…............../................./......../............../................/........

20"-27"…../….. 1509,1512./…..Feigao L-XL...../….............../...700SC../.SV27./.Proboat./..Ammo../........

24”-29”…../…..1512,1515../…..Feigao XL…...../….............../...700SC../.SV27./.Proboat./..Ammo../.......

26”-32"…../.....1512,1515../…..Feigao XL….../….............../.,..700SC../.SV27./.ProBoat./............./........

30"-36"…../….. 1515,1521./…........…………..../….. 580L...../.............../........../.............../............./........

34"-42"…../….. 1521,1527. /…........………..…/….. 580L...../................/........./................/............./........

38"-46"…../…..1527,2215. /….. ......……..……/................../................./........./................/............./........

40"-60"..../.......2230......./Little Screamer 63mm outrunner/

MOTOR MAXIMUM WATT RATINGS.

Always look at the maximum WATTS the motor is rated to handle. The heat will kill the magnets and possibly the controller if you get it to HOT.

Continuous rating/ 30 second rating

Neu -
1506 - 700 watts/ 1500 watts
1509 - 1000 watts/ 2000 watts
1512 - 1200 watts/ 2500 watts
1515 - 1500 watts/ 2700 watts
1521 - 1700 watts/ 3000 watts
1527 - 2100 watts/ 3300 watts
2215 - 3000 watts/ 5000 watts
2230 - 6000 watts/ 10000 watts

Feigao
580L - 1800 watts/
540 XL - 800 watts/ 1600 watts
540L - 600 watts/ 1300 watts
540S - 450 watts/ 1000 watts
380L - 450 watts/ 1000 watts

SV - BlackJack 800 watts/ 1400 watts

Ammo 2300 - 700 watts/ 1400 watts

700sc - 650 watts

Volts (X) Amps = Watts

Always calculate your setup Watts and prop it to run close to your motors Max Amp rating. (maximum effeciency rating)

Example:
Specs for the motor in the BJ
TURNIGY brushless Inrunner

Power: 460W
Battery Config: 3-5S

Watts / Volts = maximum AMPS to keep motor cool - recommended by manufacturer.

460 watts / 11.1volts = 41.4 amps max

460 watts / 14.8 volts = 31 amps max

460 watts / 18.5 volts = 25 amps max


FeCalc can get you in the ballpark for loaded 2-pole motor watts and amps. It is just an estimate, but can give you a good idea of which prop to start testing with.

The Feigao 540 motor max amps ratings are attached below.




__________________

[ReddyWatts]

Water Jacket - outlet hole placement

""I see that most jackets have the inlet and outlet only 90 degrees apart, and they are usually mounted with the inlet at least 45 degrees below the top. What this does is create an airlock that prevents water form getting to the top of the motor - arguably the hottest part. The UL-1 jacket as it comes on the boat is worse with both inlet and outlet side-by-side - with this configuration the top half of the motor doesn't even get water. At least mount the outlet as high as possible, meaning the top front of the motor.

Info provided by Fluid.""

Why take a chance of getting air pockets in the motor cooling jacket during a run? Place the water outlet at the top/front on the motor and let the air escape easily.

Let the water flow freely through the system. Fast flowing water, turbulence and with more temperature differential results in better cooling.

[Punisher 67]

Steven and Reddy as much usefull info as you have here for me nothing speaks as much volumes as a well placed thought out boat setup picture , before I engage any build I research many examples of that build and assess all angles and every aspect of that setup with as many examples as possible . I am a firm advocate of as many build setup pictures as one can take . for me the bulk of my learning has been through pictures , pictures of failed setups are every bit as usefull as pictures of winning setups , weather you build is a success or failure the info you supply is equally important

[ReddyWatts]

OSE's - FE Setups - Interactive Illustrators

These are great tools for a better understanding of FE setup connections.

System Wiring Illustrator


Lipo Connection Illustrator




.

[exotica]

...what a great thread!

[ReddyWatts]

Octura Prop Pitch

Thought this might help when looking for the next prop to try. I listed some Octura props with increasing pitch. This may show why going to a smaller diameter prop with more pitch or more blades can be faster. More blades means less slippage under heavier load, can be more effecient.

PROP Pitch/inches

X437/3-- 2.072
X438---- 2.100
X440---- 2.198
X440/3-- 2.198
Y536---- 2.200
Y537/3-- 2.279
X442---- 2.310
X637---- 2.368
X445---- 2.478
X640---- 2.512
X447---- 2.590
X447/3-- 2.590
X642---- 2.640
M545---- 2.655
X448---- 2.660
X450---- 2.758
X450/3-- 2.758
X645---- 2.832
Y547---- 2.849
X548---- 2.850
X452---- 2.870
X452/3-- 2.870
X646---- 2.896
X646/3-- 2.896
X455---- 3.038
X455/3-- 3.038
X648---- 3.040
X457---- 3.136
X457/3-- 3.136
M650---- 3.190
X460---- 3.304
Y557---- 3.449
X560---- 3.540

X427---- 1.498 0.125
X430---- 1.652
X431---- 1.708
X432---- 1.764
Y531---- 1.877
X435---- 1.932
X632---- 2.016
Y534---- 2.059
Y535---- 2.125

[ReddyWatts]

Waveform of a Brushless Motor ESC.

This video shows how an ESC uses a PWM waveform to control motor speed. It simulates an AC sine wave using positive and negative DC pulses. Notice how it changes the DC pulse widths but keeps a constant peak voltage during the complete throttle range. The peak voltage remains at your battery pack voltage.



Why it is best to run at full throttle.
A speed controller controls power to the motor by turning full throttle current on and off really fast, 11 to 13 thousand times per second (Pulse Width Modulation or PWM). The percentage of each on/off pulse that is off compared to the part that is on determines how much power the motor sees. I.E. With a pulse that is 50% off and 50% on the motor will see 50% power*. Because each on pulse is 100% of full throttle current, a system set to pull 20 amps at full throttle through a Phoenix 10 will not last if you are throttled back to the point where you only see 10 amps on a wattmeter. The ESC in this case is still switching 20 amps, which it can’t do for long. Because an electric motor will always to try to pull as much power as is available to get to its rpm (volts times Kv), when you are running the motor below its Kv speed by switching power on an off, each on pulse will actually be way over the full throttle amp draw. That is why ESCs work harder at partial throttle than full throttle and why we underrate our ESCs. We underrate not so they can handle more current than their rating at full throttle, but so they can handle extended partial throttle operation with no problems. CC

An amp is measured by how many electrons pass a point on a wire in one second. The narrower pulse current that is used by the ESC output during half throttle will have a higher peak current but read less on the input ammeter because it is seeing less passing electrons for the same period of time as it would at full throttle using wider pulses. This is why you dont see the high amps on the input side

m4a1user; What happens at low throttle is that the FET goes into the linear mode for a larger percentage of the on-time. That means the FET spends more time heating than it should - and hot FETs have more resistance, meaning next time they are in linear mode, they will heat up even hotter. At the same time, the motor is at lower RPM and therefore pulling more amps (a stalled motor will draw the maximum current).

You can get a lower RPM (ie, a lower average voltage) at maximum duty cycle only by lowering the input voltage. The speed control will run better with a lower input voltage even though it may be passing more amps simply because there will be less time for the FETs to be in linear mode. It is not an exaggeration to say that the FET may have 10X or more resistance when in linear mode. Heat generated is directly related to resistance.

Thank you Andy Kunz for very simply explaining this phenom to me so I can share this with fellow RC'ers

I hope this helps to clarify what PWM means and why it is better to run it wide open, than half throttle. The peak amps and esc resistance in the esc go up causing more heat at half throttle. Less work, stress and heat on the FETS running at WOT.

[ReddyWatts]

Volt/KV Chart

Posted by Detox

[ReddyWatts]

Handy Fraction/Decimal/Metric Conversion Chart

Handy chart posted by Ray R

FractionDecimalChart[1].pdf

[HydroMike]

Cool alot of nice info thanks alot

[mxrb18]

I hope by showing a structure of setups you will see the "Big Picture" for a better understanding of Fast Electrics.

There are to many variables for this data to fit all the different hull and motor loads. Many setups will fall outside this general information guideline.

FE SETUPS

--hull size /--------Cells---------/ ----Motor Kv----- / -------Prop Size------/---Type ESC---/-BEC-/ESC Amp Rating

17”- 24” / 2s LiPo or 6 cell NiMh / 5500 -3200Kv / 30mm - 40mm Diam. / Low Voltage / Avail. / 120 amp

20"-27" / 3s LiPo or 8 cell NiMh / 3500-2500kv / 35mm – 42mm Diam. / Low Voltage / Avail. / 120 amp

24”-29” / 4s LiPo or 12 cell NiMh /2650-1600Kv /37mm - 46mm Diam. / Low Voltage / Avail~Disc / 120-240 amp

26”-32" / 6s LiPo or 18 cell NiMh /1800-1100Kv /40mm - 52mm Diam. / Low or High / Disc. / 120-180-240 amp

30"- 36" / 8s LiPo or 24 cell NiMh / 1350-800Kv /45mm – 55mm Diam. / High Voltage / N/A / 180-240 amp

34" - 42" / 10s LiPo or 30 cell NiMh / 1100-600Kv /47mm + Diameter / High Voltage / N/A / 180-240 amp

38" - 46" / 12s LiPo or 36 cell NiMh / 900-550Kv / 50mm + Diameter / High Voltage / N/A / 240 amp

Always start testing with a small prop and work up to your desired amp readings!


HULL SIZE AND OSE MOTORS

This is a general guideline for the motors OSE sells. I know it is hard for this to cover all selections, since FE setups can be complex and extend over a wide range of extremes. Remember this is more for conservative setups to help new guys get started.

hull size…..... /…...... Neu….... /….. Feigao.540…../Feigao 580/...700SC../.SV27./.Proboat./..Ammo../.380.

<<"-20"....../.....1506........../.......Fiegao.S......./................./................./......../............../.............../.380 L

17”-24”…../….. 1506,1509./…..Feigao S-L…...../…............../................./......../............../................/........

20"-27"…../….. 1509,1512./…..Feigao L-XL...../….............../...700SC../.SV27./.Proboat./..Ammo../........

24”-29”…../…..1512,1515../…..Feigao XL…...../….............../...700SC../.SV27./.Proboat./..Ammo../.......

26”-32"…../.....1512,1515../…..Feigao XL….../….............../.,..700SC../.SV27./.ProBoat./............./........

30"-36"…../….. 1515,1521./…........…………..../….. 580L...../.............../........../.............../............./........

34"-42"…../….. 1521,1527. /…........………..…/….. 580L...../................/........./................/............./........

38"-46"…../…..1527,2215. /….. ......……..……/................../................./........./................/............./........

40"-60"..../.......2230......./Little Screamer 63mm outrunner/

MOTOR MAXIMUM WATT RATINGS.

Always look at the maximum WATTS the motor is rated to handle. The heat will kill the magnets and possibly the controller if you get it to HOT.

Continuous rating/ 30 second rating

Neu -
1506 - 700 watts/ 1500 watts
1509 - 1000 watts/ 2000 watts
1512 - 1200 watts/ 2500 watts
1515 - 1500 watts/ 2700 watts
1521 - 1700 watts/ 3000 watts
1527 - 2100 watts/ 3300 watts
2215 - 3000 watts/ 5000 watts
2230 - 6000 watts/ 10000 watts

Feigao
580L - 1800 watts/
540 XL - 800 watts/ 1600 watts
540L - 600 watts/ 1300 watts
540S - 450 watts/ 1000 watts
380L - 450 watts/ 1000 watts

SV - BlackJack 800 watts/ 1400 watts

Ammo 2300 - 700 watts/ 1400 watts

700sc - 650 watts

Volts (X) Amps = Watts

Always calculate your setup Watts and prop it to run close to your motors Max Amp rating. (maximum effeciency rating)

Example:
Specs for the motor in the BJ
TURNIGY brushless Inrunner

Power: 460W
Battery Config: 3-5S

Watts / Volts = maximum AMPS to keep motor cool - recommended by manufacturer.

460 watts / 11.1volts = 41.4 amps max

460 watts / 14.8 volts = 31 amps max

460 watts / 18.5 volts = 25 amps max


FeCalc can get you in the ballpark for loaded 2-pole motor watts and amps. It is just an estimate, but can give you a good idea of which prop to start testing with.

The Feigao 540 motor max amps ratings are attached below.




__________________

Do you have any idea what a suitable setup would be for a 72" CRC5000 Cat? I was considering a dual 12S setup with Tp-5680 (600kV 5Y, 800kV 4Y, or 1070kV 3Y) motors, twin ZTW Seal 300A Esc's, and 4 6S 5000maH 70C batteries (12S per motor). Any info would be awesome. I just need to determine the right motor setup to get on plane well but still achieve really good top end speed. Thank you