Basically the KV rating has no big effect other than having more Top Speed. You will just have more Amp flow at the same speed, putting everything under more strain (Contoller, Battery, Motor). Losses will be greater, due to heat & increased resistance in cables. Our motors have an efficiency of 90%, measured at 12S. Most simple BLDC motors are around 75-77%. Don't believe the 95% efficient everyone claims! Cheep motors use cheap magnets & low quality copper resulting in less efficiency, especially at high amp flow & low voltage. The reason why they cost 80 - 90 $ is because they are cheap quality! The VESC 4 is at its limits when using our Motors at 50Amp Current draw. VESC 4's work fine, but they are the bottleneck in the power not the motor.
Using a higher KV rated motor will have the effect of loosing torque at Amps your system can supply and being less efficient at cruise speed. Sure your motors are bigger and might compensate that a bit. KV seems to be a religion, but if you ask Benjamin, (Benjamin Vedder is the Dark Lord of E-Power!!) he would say: Copper fill is the only thing that really matters if your KV is somehow within the range of efficiency. Good motors have a better copper fill (hand wound), cheap motors have less copper fill & are machine wound. KV should always correspond to the realistic average speed. Peak performance at realistic average RPM! At 40Km/h we are, using our 136KV@1Nm setup, close to peak performance of the motor. Already to fast, as you can see. You never go that fast in average! This is why we use the 118KV@1Nm Motor.
All I want to say about sing the 190kv motor with 9 inch wheels is expect your setup to be not very efficient. 9" Wheels would make your motor spin even slower at the same speed, demanding for even lower KV to become efficient. Believe me, our motor's a very well balanced for the application, but of course you can always go crazy. Biggest Problem is the wheel slip anyway: When your wheel slips and get back to grip, the Ampflow shoots up very very fast. You can correct the setting in the VESC, using FOC (T: 500,0 µS).
A Twin 136KV TRAMPA Setup is a beast! It puts the tires under massive strain already! Bigger Motors just create more wheel slip & will of course wear out tires faster. We also have sensors attached to the motor stator. This feature is imperative, when riding MTBs. VESC 6 will make full use of this feature but even VESC 4.XX likes the sensors a lot. Temperature sensing should also be done for safety reasons. Another issue you could get: Your motors could output more power than ours, putting everything under more strain. We tested our drives with our motors. Dropping in much stronger motors is an experiment you are responsible for! I'm not pessimistic, just want to clarify things.
I would not connect both drives to another! Our drives are 100% aligned to each axle shafts. Due top tolerance in production of the Spring Truck Hanger MTBs never have two perfectly aligned (in line) axle shafts. In consequence, the drives will never be 100% parallel. If you align the drives to another, your drives will not align with the wheels. Slim chance you can get that straight. But for sure, belts swallow some tolerance. If one drive would become slightly loose, due to vibrations and abuse (MTB suffer alot), you would put the other drive under strain and would not realize something is not quite right. And anyway, technically speaking there is no good reason to connect them. We made our Drives, so you can use them as singe drives without any problems. Two singles are a TWIN, but each drive is set free from the other, so that they don't affect each other. So you gain nothing by joining them together!
Hope that helps you, Frank
TRAMPA's very own purpose made 136 KV Fully HALL & TEMPERATURE censored BLDC & FOC 6364 Out-Runner Motor provides 136 RPM per volt @ 1Nm. It has been CUSTOM MADE to handle HIGH VOLTAGE SET-UPS, i.e 26-44V using for example the VESC 4 & 6 speed controller. The Motor easily switches between FOC & BLDC modes running effortlessly in either mode.
The Motor houses Ultra high Temperature Copper & Ultra Strong High Temperature Neodymium Magnets. We designed an Extended & Heat treated 8mm Steel Axle shaft that's locked in position using 5 high precision Japanese Bearings, All screws & fixings used in its assembly are Marine Grade Stainless Steel, this motor easily out performs all & any competition on the market in so many aspects & its applicational use is almost endless!
Our special design allows you to to also fit metal mesh filters to prevent the impregnation of larger particles ending in your motor! The front sided motor shield is equipped with twelve M4 treads, sitting on a 44mm diameter circle. The extra threads will allow you to mount the motor in the exact angle you wish, so that the three motor cables always sit in the perfect angle towards the mount or deck.
When handling and inspecting the motor the copper's appearance is almost dark red, suggesting very high quality & looks very special on first impression.
TRAMPA's 118 kv Motor is fitted with an 38.5mm x 8mm (Extra long) Heat Treated Hardened Steel Motor Shaft, which is also fitted with a KEYWAY locator as standard! The extra length of the Axle allows us to fit Extra wide Motor Pulleys, meaning we fit a 15mm HTD 5M STRONGBELT as standard. A wider belt guarantees a much stronger power delivery. The end of the motor axle is supported with the use of a Bearing that is located in a Fixed housing, soaking up the strain of the powerful motor, & eliminating the possibility of bending the motor axle... Two 3x3x8mm KEYs lock the Axle shaft at both ends (1 into the Rotor & 1 into the Motor Pulley), eliminating all & any "Motor slip", thus providing maximum performance to the rider & gaining critical data for the VESC, ensuring all its high tech facilities can run as expected. TRAMPA's special motors are fitted with internal PCB Hall Sensors.
The Can Section of the motor has been Powder Coated White & finished with a very stylish Gold TRAMPA logo whilst the vented Aluminum end plates of the motor have been color coordinated Anodised Black. The Heavy Duty power cables use 4mm Gold Plated Bullet Connectors to connect to a power source. Typically for TRAMPA only Marine Grade Stainless Steel Fixings have been used in the assembly of this motor. & no parts will rust on you. This Motor can be connected to any of the Motor Pulleys in the TRAMPA product Range amongst others out there on the market...
60A continuous for the 136 KV
50A continuous for the 118 KV
You will never have 50A continuous anyway... maybe for a longer period if you climb a steep hill.
If you go higher, you could saturate the stator and the VESC would lose tracking.
Assume 2.4kW per motor, which is quite crazy power riding a board.
I would like to have some information about the 118kv outrunner. I'd like to know
- max continuous current (not peak current)
- maximum continuous torque
- internal resistance
You can push up to 40A continuous and get about 4Nm of torque. That depends on how much cooling you can get. Are you riding in Sweden in winter or in the Californian sunshine?
I would stay a bit below 40A continous, but the temp sensor would make your motor slow down in case of overheating (through VESC-temp control if activated).
Internal resistance: VESC-Tool states 0.037Ohms.