Correct, I will let the market decide. I did my part by discussing my experiences. The rest will be up to the companies, I agree with you on this.
Keep on innovating and pushing to be the best, but also treat the people who fund your innovations with respect and don’t lash out on them like people did with me on the other thread. Hope you fix all issues on the raptor 2.1, and when your customers are happy with it…I’ll be ordering a raptor 2.1 also
Thank you for considering making these available, it’s a good business move I think, I’m not exactly a big fan of enertion but I’m here considering these and I have two unities on order so the product is doing the talking.
Questions.
If and when you sell these “kits” will they be from the new stock? What will the feasible lead time be?
We’ve been trying to find new markets to tap with the unity. Doorstoppers is a whole new avenue we hadn’t even considered… think of how many doors there are.
The 270 KV motor would run at 3x higher RPM and 3x lower torque output and would generate 9 times less losses. There is a reason why everyone uses gears in applications involving electric motors. Torque output and losses go hand in hand. There is an optimum RPM/torque relation for each motor size.
Urethane insulation: If you want to compare heat output you need to compare a Carvon style system with a geared one. Both motors would get quite good cooling and can radiate heat via the can. The carvon style system would still run a lot hotter due to the 3x higher torque output at 3x lower RPM.
My testing has shown that with these limits somewhere around 110C the motor current is reduced sufficiently that the motors never exceed 110 while remaining rideable over everything but the steepest of hills.
Please note that you always need temperature headroom for the brakes to work. If you ride with 110°C hot motors and you hit a downhill section with these hot motors you don’t want the ESC to cut out power when the motor works as a generator for a longer period of time. You also don’t want to overheat the motor further potentially killing the motor and loosing brakes this way.
Benjamin implemented the acceleration temperature decrease setting to make sure your motors would have 14% temperature headroom for full brakes. In consequence you can’t hit a downhill section with a motor that is hot already. Since BLDC motors have a long term temp limit of a bout 105°C (magnet glue, max temp rating of thermistor and hall sensors) the ESC should cut back power softly at roughly 85°C so that you won’t hit the temp limit when you need the brakes to work.
Reason for the setting: There was an accident reported that happened due to a motor that melted under the long time heat exposure (possibly over months). The rider was very lucky and didn’t get hurt. Car pulled out, no brakes… For the safety of the riders Benjamin implemented the acceleration temperature decrease setting and set a standard of 14%.
That 15% setting is in place. our thermistor is bonded very closely to the windings. Testing shows the can temperature stays a good bit cooler than the windings, I’ve tested and will continue testing the thermal settings to ensure safety.
Also your math on the motors is just wrong… I’m really too tired to write it out at the moment. It’s my job to know and understand these things intimatley, if you really want you can continue arguing with me and I’ll run some simple numbers in the morning to show what your saying is incorrect. For the record gearing can increase efficiency depending on application… the factors of 9x or whatever you’re claiming are what’s ridiculous.
EDIT: I’m an asshole . Couldn’t sleep with numbers bouncing around in my head. So humbling when I behave rudely and then don’t even have the decency to be correct. Sorry @trampa. Here is some quick numbers. I’ll use the excuse that I’m a bit tired to save some of my ego. Need to learn more respect for guys who have been around longer than me.
They are the same motor wound differently to have a 135 vs 280 kV rating. For simplicity lets just round 135 to 140 and say one has twice the kV. So lets say we use the 140 kV with 1:1 ratio (hub) and the 280 kV with a 2:1 ratio pulley. We can agree since rpm/volt is double the max speed after the gear ratio between the two is identical. Now an important point is that the motors torque constant varies inversely with kV. That is to say 1 amp in the 280 kV motor will provide half the torque of 1 amps in the 140 kV motor. Assuming a perfect gearbox (reality will be in the 0.7-0.95 range depending on transmission efficiency) then at the output both motors should need about the same amps to generate comparable torque. lets say 20 motor amps for our example. We can calculate motor losses as (winding resistance)*(motor current)^2
For 135 kV 1:1 ratio I calculate losses as: 37.6 Watts
For 280 kV 2:1 ratio without losses I calculate losses as: 9.2 Watts
For 280 kV 2:1 ratio with aggressive 20% losses through gearbox I calculate losses as: 14.4 Watts
Again sorry my mistake! the last thing I want to do is spread mis-information. Let me know if I made a mistake somewhere. The efficiency will depend on the speed the board is going obviously.
i’ve read that the VESC tool estimates 1-phase resistance for FOC calculations (lead to lead divided by 2)… assuming this is true it gives a lead-to-lead (2 phase) resistance of 0.096ohm in BLDC.
80a * 80a * 0.096ohm = 614.4w ohmic heating at full throttle
^if the vesc tool measures 1 phase, the heating is 614.w at full throttle, assuming 80a motor current limit
80a * 80a * 0.048ohm = 307.2w ohmic heating at full throttle
^if the vesc tool measures both phases, the heating is 307.2w at full throttle, assuming 80a motor current limit
since we have 2 motors attached to the truck we can calculate the total heating transfer by multiplying this heating x 2:
80a * 80a * 0.096ohm = 614.4w ohmic heating at full throttle
614.4w * 2 motors per truck = 1228.8w heating/loss per truck @ full throttle
80a * 80a * 0.048ohm = 307.2w ohmic heating at full throttle
307.2w * 2 motors per truck = 614.4w heating/loss per truck @ full throttle