Ideas on Building a Reliable BL System by ReddyWatts.
Ok I told Reddy that I would post this in the "Tips & Info" Section of the site, but haven't had the time to do so. So we don't lose it on the old forum I'm going to post it here and stick it to the top for a while.
Ideas on Building a Reliable BL System by ReddyWatts.
I have written down some ideas for building a reliable, brushless boat from what I have learned from the OSE forum and experiences. Keep in mind; this has nothing to do with racing. It is for the novice that wants his new hobby project to be dependable.
1.Use no more than 8 inches of total wire between the batteries and the controller.
2. Use a .150 flex cable or larger on 12 cells or more. Use a .130 flex cable on 12 cells or less.
3. Use a 12XL to 14XL or larger motor with direct drive on catamaran, mono hulls 29 inches (1/8 scale) and above. Most hulls have a min/max recommendation for how many NiMH batteries it will handle.
4. Use a 6XL to 10XL and 12L to 14L series motors with direct drive on 28-inch to 22 inch (1/12 scale)or less hydro type, catamaran or mono hulls. These motors have a higher rpm/volt rating and use fewer batteries. This allows for high speeds with less weight and motor torque.
5.Use a 6S to 14S and 6L to 10L series motors with direct drive on 21-inch (1/16 scale) and smaller hydro type, catamaran or mono hulls. These motors have a higher rpm/volt rating and use 6-8 cells (S series) or 6-12 cells (L series).
6. Limit the loading of your controller to 60% amps and 75% voltage of its max ratings, 14 cells and above, due to current surges and boat weight.
7. Limit the loading of your controller to 70% amps and 75% voltage of its max ratings, 12 cells or less.
8. Design your boat to run with the “wide-open” amps at your motors "maximum" efficiency rating.
9. Install floatation in your hull, unless you are a certified scuba diver.
10. Grease and maintain your flex cable regularly, to keep it turning freely.
11. Make your flex cable metal tubing long enough to cover most of the flex cable, to prevent blowouts.
12. Use an ammeter to measure motor load. I suggest two different brands.
a. The "Watts Up" meter from Offshore Electrics. Look for it under, Tools.
It is a “peak recording”, ammeter for $50. It is very simple to use.
b. The Eagle Tree Micro "data logger" for $70 at Eagle Tree Systems. It will record your amps for the entire boat run and has add-ons for temp, display and rpm. It gives very detailed information and also works with a computer or an attached display.
www.eagletreesystems.com/.../micro.htm
13. Start amp testing with a small prop and move to larger ones until it is loaded to the motor maximum rating and not overloading your controller guideline. The larger your prop the higher your amps will go.
14. Use an infrared temperature meter to measure equipment maximum readings.
15. The maximum temperature reading for a controller is 150 F, the motor is 150 F and the batteries are 150 F. Always try to keep the controller and motor as far below these readings as possible with water-cooling, but the best way is lowering your amps.
16. Keep the receiver away from your battery wiring and run these wires perpendicular from each other if possible to minimize interference. Twisting receiver cables can also minimize interference.
17. Brushless controllers are more efficient when running them wide open.
18. Leave the controller "timing" option at factory default/low. It will not increase your speed by changing the setting, but will make the controller run hotter.
19. The first link below is to the FE Calc program. Download it to your computer for free. It is great for simulating a setup for your boat. Remember these guidelines when considering your maximum amps for your controller. This program does not calculate all of the variables, so start testing with a smaller prop than it calculates for your desired setup. You can add more equipment to the program if yours is not there, by adding it to the text file that comes with it.
Example: Use the second link below to get all of the Feigao motor information. Some are listed below.
www.rcboataholic.com/fe_calc.htm
img.diytrade.com/cdimg/85...223033.jpg
Feigao 540-12S 2958 2.1 .0136 B-Less 12 8 300g
Feigao 540-8S 4436 5.5 .0060 B-Less 8 8 300g
Feigao 540-9XL 1853 2.5 .0092 B-Less 9 16 372g
Feigao 540-10XL 1668 2.3 .0114 B-Less 10 16 372g
Feigao 540-12XL 1390 1.9 .0164 B-Less 12 16 372g
Feigao 540-14XL 1191 1.2 .0223 B-Less 14 16 372g
20. Using a transmission can soften current surges and make your setup more forgiving. You can load an 80-amp controller to 80% of its amp rating and 80% of its voltage rating. It makes for a very versatile setup, using different ratios. You can use any motor with a trans in a cat or mono hulls, but the trans also lowers your reliability. (Gears)
To use the FECALC for transmission setups, just divide the RPM/Volt value by your selected gear ratio;
Example: 10XL with an rpm rating of 1668 per volt and you are running a gear ratio of 1:33 to 1,(60-prop/45-motor), divide 1668 by 1.33 which gives you 1254 rpm, so if you look in the text file for a 10XL 1668 change the 1668 to 1254 and save." then reopen FECALC and "calculate".
21. Disconnect your middle wire (BEC) between the receiver and the controller, when using more than 12 cells.
22. Buy the controller last for your boat project. There is a sixty day replacement warranty from the date of purchase.
23 The balance point for a catamaran or mono hull is from (2/7) 28% to (1/3) 33% from the rear of the hull.
24. The balance point of a hydro type hull should be an inch or two behind the front sponsons
25. You can change the rotation of a brushless motor by swapping two of the three wires going to the motor.
These brushless motors are like 3 phase electric AC motors. The windings are connected in a "TRIANGLE". Picture the motor windings connected between each corner point. "A" on the top corner, "B" on the bottom right and "C" on the bottom left. The electric pulses out of the controller alternate pulsing to the motor wires in this order. a-b wires, b-c wires, c-a wires for each motor rotation. So if you swap "B" and "C" wires, it now reverses rotation around the triangle by going in this order. a-c, c-b and b-a. Therefore you cannot wire these motors up wrong, it only changes the direction of the rotation
26. Props are a critical item for your boat to perform as desired. There is a huge selection to choose from. This is a cheap option and usually the first step to make a stock boat run faster.
Carbon Fiber Props are light, sharp and don't need to be balanced or sharpened. They cost ½ the price of a Beryllium copper prop. They are great to use when testing your setup with many different props. They can flex under heavy load and shatter if they hit something.
Beryllium Copper props need be balanced, sharpened and can be polished. Great to use after you have selected a permanent prop for your setup. It will take about an hour to balance and sharpen one properly. You will need to purchase a prop balancer. I suggest the: “Top Flite Boat Prop Balancer”.
Do not inhale the filings or dust, it can make you ill. Be careful with contamination.
Aluminum props are fragile and flex under load. Unless you find a really good reason to use one (they don't need balancing isn't good enough) you should stay with BeCu (Octura) or bronze (Prather). Prather also sells a stainless steel prop.
Stainless props are much harder than beryllium and as a result it takes alot more sanding and working to sharpen, thin, balance and polish.
FORMULAS
To calculate run times
Battery Mah rating (times) 0.06 (divided by) motor load in amps = run time
Example: 3300 MAH (X) .06 (divided by) 35amps = 5.65 minutes of run time
To calculate your average amps
Battery Mah rating (times) 0.06 (divided by) run time = average motor load in amps
Example: 3300 Mah rating (times) 0.06 (divided by) 5.0 minutes = 39.6 amps
To calculate your geared RPM.
Motor shaft teeth (divided by) prop shaft teeth = multiplier.
12 motor shaft teeth (divided by) 24 prop shaft teeth = .5 multiplier
Motor RPM (times) .5 multiplier = geared prop RPM
To calculate your gear ratio.
prop shaft teeth count (divided) by motor shaft teeth count = gear ratio.
24 prop shaft teeth (divided by) 12 motor shaft teeth = 2/1 gear ratio
Meaning your motor turns (2) revolutions for each prop (1) revolution.
To calculate motor horse power
amps (X) volts (X) efficiency (divided by) 746 = horsepower.
Example: A 540 10XL was using 65 amps X 21.6 volts X .91 eff. / 746 = 1.7hp
I wrote this guideline, hoping it will help everyone to have a positive new experience with a brushless boat.
ReddyWatts
Updated 10/11/2006.
Octura prop descriptions.
Thanks Part Time and D. Smock, good info about props!
Different types of Octura props
12 are low lift ideal for submerged drive
X4 are medium lift general purpose props
M4 are like X4 but with the tongues removed to unload the prop
Y are like X series but have 10% more pitch
X5 are general all purpose med lift prop
X6 are higher lift than X4 and suitable for surface/semi surface use
14 are moderatley high lift for hydros and deep V's
16 are high lift props for riggers and hydro's
17 are the highest lift prop for riggers and outboards
P7 are similar to 17 series but more rake and less lifti
19 are high lift for riggers and hydro's
V9 are moderate lift suitable for riggers, hydros and SAW racing
20 are moderatley high lift suitable for riggers
21 are high lift for riggers and hydro's 22 are high lift surface drive only good straight line speed
Understanding Motor Poles
Lehner, Feigao, Hacker, Nemesis, KB45, Ammo 2300 have 2 pole brushless rotors.
Neu, Plett have 4 pole rotors.
Mega, BK, 27SV, Blackjack-26 have 6 pole rotors.
MHZ/Shark has 8 pole rotors.
For a 2 pole motor rotor with 3 stationary outside stator coils, the controller will energize a stator coil 3 times in each rotor revolution.
For a 4 pole motor rotor with 3 stator coils, the controller will energize a stator coil 6 times in each revolution.
For a 6 pole motor rotor with 3 stator coils, the controller will energize a stator coil 9 times in each revolution.
2 pole energizes a stator coil every 120 degrees of rotation.
4 pole energizes every 60 degrees.
6 pole energizes every 40 degrees.
BL sensorless controllers use the feedback pulse from the wire not being used while it is energizing a stator coil to AUTOMATICALLY sync with the rotors of the different pole motors.
The more poles the motor has gives it more torque for pushing larger hulls, weight and props.
Increasing number of poles:
The number of motor poles can be increased to gain some improvement in motor torque. There are more conductors, resulting in more current that the rotor may accept. An increased number of poles will also produce a stronger magnetic field. For example, a 2-pole stator of 80-mm diameter and 90-mm length will output around 1.7 Nm torque; a 4-pole motor will output 2.3 N-m torque. A 6-pole motor in the same size would have about 2.8 N-m torque. While higher motor torque can be achieved by using a motor with a greater number of poles, this requires a higher output frequency to run at similar speeds.
A 4 or 6 pole motor is more forgiving than a 2 pole when accidently over propped. The current surges are not as high.
Some controllers can have problems running 4 or 6 pole motors. The Schulze and BK controllers have problems with the Neu Delta 4 pole motors. Hextronics and other brands of controllers with "out of date" revisions of software can have problems.
"Cogging" The controller does not stay in sync with the rotor at lower rpm's. The motor runs and sounds real ruff or can jump back and forth, but smooths out at higher rpms.
IMO, if a motor is not loaded properly for a controllers dynamic timing range, (to much or to little load) it will run hot.
Here is an explanation of running an ESC at half throttle from Castles site, given to us from Fast Guy.
"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. Actually it is worse than the simple example above. 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."
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Delta or Wye winding motor?
Neu and Lehner offer brushless motors with wye or delta winding connections. I always wondered, "what is the difference in performance", so I will try to explain, what my simple mind could understand about it. Hope it helps.
The WYE motor winding is used in higher torque or higher voltage applications. Typically, DELTA motor winding is used in lower voltage or higher speed applications. A motor with windings in delta configuration gives low torque at low rpm, but can give higher top rpm. wye configuration gives high torque at low rpm, but not as high top rpm.
If you take a Wye winding motor (1000kv)and change it to a delta winding motor you will see it change to 1732kv. You will see a higher kv motor with less torque. Torque will be reduced by 43%. ("KV" is how many unloaded rpm the motor will run for each volt that is connected to it.)
Three phase motors come in two wiring patterns. It is called Delta because the three phases are hooked together in a triangle arrangement. Phase one uses terminals A & B. Phase two uses B & C. Phase three uses C & A. In electrical talk the phases are 120 degrees out of phase with each other. You could think of it as firing order in a multi cylinder gas engine. The Electronic Speed Control (ESC) first talks to or sends power to phase one. Then it waits 120 degree and sends power to phase two. And at 240 degrees it sends power to phase three. At 360 degrees (120 X 3) the whole process starts over again.
Y wind where each leg of the Y is a phase and the center of the Y is common. Y wind typically has higher winding resistance as two windings are in series for each phase. This is why some controllers have problems with delta motors. Delta gives a lower voltage feedback pulse to the controller.
The delta winding could be used in a a lighter, lower voltage. high rpm setup or a hydro that does not require a lot of torque. The more effecient wye winding works in all applications and is better for heavier mono or cat setups.
EXAMPLE of the same motor wired delta and wye.
NEU
1521/1.5y = 1050 rpm
1521/1.5d = 1850 rpm
1521/1.5Y will handle from 8-55 volts and is a 90%+ effecient motor with more torque. Max effeciency amps 50.
1521/1.5D will handle from 8-32 volts and is a 85%+ effecient motor with less torque. Max effeciency amps 90.
All rating calculations between the motors have a 1.732 relational value between a Wye and Delta connection.
Thanks to Skeeler for this information;
Neu motors are named DDLL, where DD is the stator diameter, and LL is the rotor length, both in tenths of an inch. For example,
1512 motor
Stator diameter: 1.5 in
Rotor length: 1.2 in
http://www.drcwebservices.com/ffe/neuspecs.htm
Quote:
Originally Posted by
Fluid
Wow, a pretty old thread! But looking at it again with two more years' experience I think the above is just a bit too simplified. To say that the WYE motor has more torque is not always true in the real world - in other words in an FE boat. An example would be two motors suited for 6S boats, the 1527/1.5D (1500 Kv) and the 1527/1Y (1250 Kv). In the same boat the DELTA motor appears to have a lot more torque, as the boat accelerates much harder than with the WYE wind. So in the same application, the D has the edge for raw power. The Y is a bit easier to drive as the power delivery seems more linear, due to the reduced torque.
To say that DELTA motors are for low voltage use is not quite accurate either. The 1527/3.5D (probably not available two years ago) has a Kv of 660 rpm, not very conducive to a low voltage setup.
The difference here is due to the Kv, not the wind type. The 1521 motor is rpm limited, and the theoretical rpm at max voltage for each is:
1521/1.5Y = 58,000 rpm
1521/1.5D = 61,000 rpm
The maximum motor speed (due most likely to the bearings used) is 60,000 rpm, and the voltages listed above are the closest to that limit.
Quote:
Fluid; too little TIMING causes poor performance and excess heat. There is no "general rule" for timing advance, it depends entirely on the motor design and the amp load on the motor. I don't know where this idea of "0" timing advance came from, but it is very ill-advised for 2-pole motors.
The reason for timing advance is to allow enough time for the next coil to energize and build a magnetic field to attract the next advancing magnet. The more wire in the coil or the more amperage drawn, the more advance is required because it takes time to charge the coil. If there is too little timing advance, the coil will energize too late, hurting efficiency and building heat. Bottom line - too little or too much are both bad. You need to experiment to find the optimum for your setup....
I always ran my own turn 2-pole motors with between 10 and 15 degrees advance for oval racing applications where amp draw was 60-100 amps, and up to 25 degrees for SAW attempts drawing over 200 amps. I run 13-17 degrees with my 4-pole Neu "Y" winds pulling 140 amps, and 4 degrees with the "D" winds pulling 160 amps. My Scorpion 8-pole motor likes 15 degrees pulling 80 amps. Clearly there is no hard and fast rule for all motors.
About all I can say with certainty is that "0" degrees is almost always wrong
.
The Delta winding motor is less effecient.
Delta winding connection on left and Wye on the right.
FE Acronyms - "Fast Electric" boats
Diegoboy was thinking about the new members coming to the forum and how some of our conversations could get a little difficult to understand with all the abbreviations we use. Here are a few that came to mind.
Aft = Back of boat
AKA = Also Known As
BB = Ball Bearing
BEC = When using the ESC "Battery Eliminater Circuit" to power the receiver on the middle red wire coming from the esc instead of using an extra set of batteries
BL = Brushless
BTW = By the Way
BUMP = A text response to get the thread back to the top of a forum
CA = Cyanoacrylate Adhesive
CC = Castle Creations
CCW = Counter Clock Wise
CF = Carbon Fiber
CG = Center of Gravity (Also COG)
CNC = Computer Numerically Controlled
CW = Clock Wise
DR = Dual Rate (A switch on the transmitter to allow more or less servo travel)
ECM = Electronic Counter Measures
EPA = End Point Adjustment
ESC = Electric Speed Control
FG = Fiberglass
Freq = Frequency
FRP = Fiber Reinforced Plastic
FWIW = For What Its Worth
FS = For Sale
FYI = For Your Information
HOC = Hot Off the Charger
IIRC = If I Remember Correctly
IMO = In My Opinion
IRL = In Real Life
Kv = RPM (revolutions per minute) per volt - Kv (multiplied by) Voltage = RPM
LHS = Local Hobby Shop
LiPo, Li-Po, Li-Poly = Lithium Polymer (battery)
LSH = Limited Sport Hydro (hydroplane)
LSO = Limited Spec Offshore
LVC = Low Voltage Cutoff
mah = Milliamps per hour
Newbie, Newb = A new person or beginner
NIB = New In Box
NiMh = Nickel Metal Hydride (battery)
OP = Original Post (post # 1 in the thread)
PCM = Pulse Code Modulation
PPM = Pulse Position Modulation
Prop = Propeller
Prop Wash = The water movement created by a propeller
RFI = Radio Frequency Interference
RPM = Revolutions Per Minute
RTR = Ready To Run
Rx = Receiver
SAW = Straight-A-Way
SS = Stainless Steel
TBD = To Be Determined
TMI = Too Much Information
Tx = Transmitter
W/ = With
W/O = Without
WOT = Wide Open Throttle
WTB = Want To Buy
XTAL = Crystal
FeCalc updated Information file
FeCalc is a computer program that is great for estimating which prop to start testing with for 2-pole motor setups.
Download the program here.
http://gallery.offshoreelectrics.com...?album=6&pos=6
http://www.offshoreelectrics.com/dow.../FEPackage.zip
You may download the attached text file into your fecalc program directory and replace the file there. This one has some of OSE's Fiegao, KB45 and Neu motors. Also the NeuEnegery lipo's 1P and 2P.
There are many variables in FE boating that keep this from being an exact science. These calculations are only ball park figures. Always start with a prop smaller than what you calculate for max amps and then work up to the larger prop as heat and amps allow.
Use the "Hydro / performance" setting when calculating a 4-pole Neu motor in a cat or mono hull. The amps will read too high if you dont by 20 -30%.
Updated FeCalc info file with the OSE motors.
FeCalc Text file data
.
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.
Water Jacket - outlet hole placement
Quote:
""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.
OSE's - FE Setups - Interactive Illustrators
These are great tools for a better understanding of FE setup connections.
System Wiring Illustrator
Lipo Connection Illustrator
.
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Handy Fraction/Decimal/Metric Conversion Chart
Handy chart posted by Ray R
Attachment 66641
