The Stage | Hummie Deck | Gummies | 6.5" Trampa Treads | Geared and DD | Dual VESC 6 | Dual 6355 | 10S5P | 3D Print

That board of yours is too fresh!

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Don’t worry, by the end of tomorrow it will be plenty dirty, already have a path planed to test it in all kind of terrains

Another thing I forgot to mention, I don’t know how I could live without sensored motors, half of the test ride was stopping or rolling backwards on a hill and going forward again effortlessly, such wow, much fun

You can also use the throttle as a hand brake in uphill, if I’m not mistaken hand brake is supported in 3.40 firmware, but I will only mess with it after my trip, don’t want to screw something up and end boardless

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I always use a slight throttle as handbrake when stopping at a light on a hill. If I brake for long though, the starting torque is a bit less though. I am not sure why.

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Do you use temperature sensors on the motor? It could get warm enough to reduce power

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That makes sense. I am using TB motors, they do have temperature sensors I think.

Same problem here, will say more bellow.

Second ride done, lots of thing to say

First, the Gummies. With the Kegels I could ride 40% of the city comfortable, 30% doable but really slow and the remaining I couldn’t ride, now I’d say 80% is comfortable to ride and the last 20% I have to take it slower but much faster than with the 80mm wheels

The bad is the consumption, 13.7 Wh/km. that’s 41% more than with the Kegels, geared for the same top speed, limited to the same top speed and with the same current limits. Some more rides are needed to see if it’s just me that is ridding faster due it being so stable or if the larger diameter has that much influence in rolling resistance

Second, the same problem as @mishrasubhransu, I need to find out the correct beta factor for the thermistors, no way my motor is reaching 75°C, the VESC is limiting power all the time

And last, got it a bit dirty and with some scars, didn’t try the dirt trails because it rained a lot last night and the phase wires hole is not waterproof yet

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Ok, did a ride limited to 25 km/h, 9,84 Wh/km better, but the wheels definetely consume more than the Kegels

Also checked both vesc’s data and they are identical, so it’s not any loss on bearings or belt tension

I think one of the thermistors are bad, even at ambient temperature they are a few degrees off from each other, I will try to measure the beta factor tomorrow when I open it again to finish everything

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Do you need a metr module to use the metr app or can you just get an bluetooth uart bridge?

For the Metr app you need their module, I think it’s worth a lot, the support is fenomenal, any bug you send to @rpasichnyk and they look into it right away

Calculated the B values taking measurements at ambient temperature and then heating everything until steady state with a hair dryer, they are not far from the original, but since the calculations is logarithmic it can make a big difference

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water at a boil is at a very specific temperature. :slight_smile:

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Indeed, I will see if I have a spare thermistor, not going to put my motor in 100 °C bath :smile:

My biggest fear it’s no the motor itself, but the epoxy that is holding the hall sensors, it’s only rated to 80°C, can probably take more since it’s not unde any load

Ice water is also a good reference.

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Both extremes, I was reading about the standards, apparently the factor is calculated between 85 and 25 °C

But the main issue is that I tough my motors weren’t getting this hot, time to go go 6355. Just kidding, they wouldn’t fit with my current mounts and too much work, just wanna ride for a long time before changing anything

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Now it’s 99,9% done

Battery capacity led’s wired up, enclosure closed and threadlocked, motor wire holder a in place, a crack in the enclosure repaired and one pulley cover installed, just waiting for another one finish printing

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what size spacer did you use between your bearings? I was gonna use 16100 bearings to put on 10mm axles (10x28x8). Trampa says that superstars need 34.2mm of clearance, since they use 12x28x8 bearings does that mean I need an 18.2mm long axle spacer?

Exactly, I make mine with 18.2 and they were a little too big, but since I used retaining fluid on the bearings they aren’t loose

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very nice build :+1:

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Thanks @sebaszz

First ride in real city, and I almost died lol

The motor reaches 75°C during an extended climb, and when going down on the other side I no brakes when approaching a red light

I’m still not believing that these reading are correct and as a remedy for the time being I increased the temp cut off to 95°C and reduced each motor current to 35 A

It seems looking at the logs that the hysteresis of the temperature measurements is too great, the VESC should reduce power between 75°C and 85°C, but by the time it reaches the lower limit the core is already hotter, even if you just cost with no throttle or brake the temperature keeps climbing

Other than that this board is perfect for a dense urban environment, the wheels make going from bike paths to sidewalks to roads a breeze, and I can ride in the middle of traffic way more comfortable

The hall sensors make a lot of diference on intersection to quickly accelerate in front of traffic

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I’d get one of them cheap ir temp sensor guns and check the temps.

What was the outside temp?

Compare the temps from the motor reading and the gun then play with the thermistor value to get it right. Of course if the readings are correct then I am a bit surprised they also heat up reasonably fast.

I thought this was only a hub and direct drive problem that they heat up.

I can’t really test it myself though since there aren’t really hills around here.

I have a IR gun, but is hard to get the windings temperature since the opening is too small, and the difference between then and the outer parts can be really big since you have just an air gap to conduct the heat

One thing that could help is thermal paste between the motor and the mount, not expecting much any degree cooler can help

Roda again after lunch, no luck, still reached 95°C at the top of a not so long hill so I stopped before going down and upped to 150°C and if I cook it so be it

Next plan is lower the current to 25 A on each motor, but I guess the problem will continue since the average current is low, I have to open the logs on PC to see the mean of the hill climb only