thermometer stickers, do people use them?

[DogDipstick]

No drip loop?

No, but that is a good idea. perhaps I will integrate those into the systems I build in the future.

My phase wires are the slightly larger-but-not the big 8 gauge ones. They are "U-V-W 3mm² Cross Section of Phase Wire (not include insulation layer)" ( quote from ad I bought from) and it was in a sheathing when I first got it. I opened it once because of a suspected hall sensor fault ( it turned out it was a glitchy controller not the hall sensor) and cut off the OEM wire sheathing and replaced it with loose white wire sheathing like this: ( they were starting to melt slightly: this was my easy fix for that... )

And since then it has accumulated water. I think the capilary action just pulls it in every wash. I opened it for fun once just to see the Hall sensor fix was still OK but it literally had a liter of water in it.. Runs fine. On very very cold mornings it has recently been frozen solid: Cant lever it with a four foot lever to turn. Picks up the bike, before it breaks loose... . but the throttle will break it loose. Lol. Frozen solid until you hit the throttle or thaw it out. I drag it, locked up, into the house or into the sun for a few hours.

Its getting bad. Doesn't freewheel one revolution if you spin it by hand.. Feels like a cement mixer with the bad bearing. ( .. that you warned me about a long time ago, I might add.. the ATF possibly softening seals or washing our grease...., like a year ago plus grrrr) Gonna open it soon and take pics. Just wait for those.

 

[Steven Sheng]

The thermometer sticker can only measure the temperature of the motor surface. Actually, the hottest part of the motor is inside. So the thermometer sticker doesn't seem to have much effect.

Thermometer stickers of different prices, the technology used is very related. Including the quality of heat-sensitive coatings, durability. Bad quality stickers, the measured temperature is inaccurate, there are errors. And in the case of large temperature changes, the sticker is easy to fail.

So this kind of sticker is not very practical, just for fun.

 

[Steven Sheng]

If you want to know the temperature inside the motor, you can make a temperature measurement module inside the motor. The controller also needs an extra wire to connect to the motor.

 

[jimmyhackers]

i get that the best way to monitor temps is a proper internal sensor...on the stator.... but thats long/envolved.

id also guess that statorade and oil coooling would actually increase the bell housing tempreture, as thats where it should be transfering the heat to.

i guess a combination of the two would be ideal.

i just remember a really old post on here of someone saying my kind of motor (1kw brushlees gearless rear hub) can do about 2kw with air cooling (holes in the bell housing) or upto 6-7kw with the oil cooling mod.

seeing as i dont fancy air cooling....im going to have to go oil cooiling. might fasion up a passive duct to force air over the bell housings on the hub motor if it gets too toasty.

 

[E-HP]

i get that the best way to monitor temps is a proper internal sensor...on the stator.... but thats long/envolved.

id also guess that statorade and oil coooling would actually increase the bell housing tempreture, as thats where it should be transfering the heat to.

i guess a combination of the two would be ideal.

i just remember a really old post on here of someone saying my kind of motor (1kw brushlees gearless rear hub) can do about 2kw with air cooling (holes in the bell housing) or upto 6-7kw with the oil cooling mod.

seeing as i dont fancy air cooling....im going to have to go oil cooiling. might fasion up a passive duct to force air over the bell housings on the hub motor if it gets too toasty.

I think Statorade and your sticker might be the next best thing to an internal temp sensor, if you could get a feel for what the stator temp is relative to the motor case temps. I can bring my IR temp gun with me when I go out riding today, and see if the internal to external temps track each other consistently/linearly. If the relationship is consistent, then the stickers may be a reasonable approximation of the stator temps. If not, the stickers would only be as good as the hand test.

 

[99t4]

might fasion up a passive duct to force air over the bell housings on the hub motor if it gets too toasty.

Were you thinking of a ram-air intake and tubing directing increased airflow to the motor covers?

Similar to brake cooling for racetrack vehicles.

From https://rooducts.com/3d-printing-in-motorsports/heres-a-nicely-done-study-of-brake-cooling/

 

[jimmyhackers]

lol maybe, but passive. i doubt ill need them in england really.

i did always wonder about getting the hubs bell housing "finned" or fine grooves cut in to increase surface area and help heat dissipation..... but it seem oil cooling alone puts as much power as id ever need (and over) on a pedal bike.

i dont really think id want more than 3kw on a bike.
even my curent 1000w hub run at 1500w compared to my mates larger 3000w hub run at 3000w. my top speed is higher and acceleration is comparable/slightly worse. he even runs a better quality higher voltage battery (sags less than mine).

like im sort of stumped asto wether i got a good motor and he got a bad one. he said he even asked for the highest torque (lowest kv motor)
to me it seems mad that double the amps (torque) would be such a minimal gain in acceleration.

although riding his bike it does feel rather saucy, like it is double the power.

hence me wondering about my motor.....is it better to overrun a smaller motor past spec (sort of safely) than get a bigger motor thats run on spec.

on my silly little e unicycle hub motors that were 200w rated (as a unicycle).....they topped out at about 700w before i wouldnt see a power increase even on a 1500w controller. i just wonder what the power draw limit on my 1000w motor is, how much wattage can i feed it befrore it starts giving zero returns. and if its 6kw (or even 3kw)....why people dont just get a cheap "1000w" motor and oil cool.

like my firend paid about double for his hub motor. seems mad

 

[DogDipstick]

i dont really think id want more than 3kw on a bike.


hence me wondering about my motor.....is it better to overrun a smaller motor past spec (sort of safely) than get a bigger motor thats run on spec.


like my firend paid about double for his hub motor. seems mad

This was my idea, with my 1kW motor run at 3.3kW. Dont get me wrong, I have ridden all three.

#1 The " underpowered big hug at stock levels"
#2 The "overpowered little hub at 3x stock levels"
#3 The " overpowered big hub at 3x stock levels"

The #2 was certainly the funnest and the most useful. Efficient for a 35H 1ooow rated motor.

#1 sucked, IDK if it was the battery ( BTR 72v pack) or the controller ( SABVO 150, 3kW controller) but it sucked. My lil 1kW overvolted hub on 3.3kW ate it for breakfast.. but..

.... #3? ... the overpowered ( 8kW contin controller ) big hub was a neck breaker.. would go up the steepest 15% grade at 55mph... No hesitation. Never ever go full throttle from a stop, goodbye bike, you are sitting in the road on your ass. Be carefull at all times. I know if I overvolted my lil hub to this level of power something would melt in an instant.

I AM, about to replace the 3.3kW controller with a 4.5kW controller, very soon, on my little hub motor, go for 4.5kW contin on a 1kW motor.. @ the same voltage, we will see if it finally melts something.

I now I dont need to break my neck. So I am very happy with the 1kW motor, with cooling fins. I have a big motor here, in the box. It just sits. It is twice as wide as my 1kW motor. Silly heavy. Yes, my 1kW motor is taking a beating at 3.3kW and will need a rebuild soon.


Alot has to do with loaded RPM being within 9-10% of the unloaded rpm. If your bike cannot do this ( level of power output vs tq. at speed), with you on it, you have the wrong kV for your wheel size and will bog, lope, lugg, waste power. Any motor will either be luggy ( high kV) or slow ( low kV).. so you have to find the sweet spot I think. Better be slow, than luggy, as long as your loaded RPM is within 10% of your unloaded RPM. Current drops as back EMF is reached.

It takes ALOT MORE power to spin a biggie (2x mass, weight) motor up than a minnie ( 1x mass, weight, in the same circle). i think. It gets more complicated than that, I think, but you get the idea.

 

[E-HP]

Here's some comparisons.
1st row - Starting temps
2nd row - After climbing 0.21 mile, 14% grade, 30 mph
3rd row - After a short time of cooling
4th row - Continued riding at 40C-45C for one hour

My conclusion is that if the temps are rising to melting levels, the external temp measurement probably won't rise quickly enough to prevent meltdown. The external temp may correlate with the internal temp, if kept at a steady state for a long enough period. If I remember to bring my temp gun, I'll try another test later this week, bringing the motor up to 90C or so.

 

[jimmyhackers]

thats some good info to know. i guess there is limited proportionality between hub temp and internal temps.

i kind of figured anything over 4 or 5 kw was just bragging rights/wasteful... as top speeds are pretty much identicle.

is alwasy funny when you see someone be told to be carefull as the bike is dangerous, but they dont belive them. Only to be flat on their arse in under 2 minutes.

https://www.youtube.com/watch?v=xtZpmyOLfFQ

even professional superbike riders.

 

[amberwolf]

i kind of figured anything over 4 or 5 kw was just bragging rights/wasteful... as top speeds are pretty much identicle.

depends on the usage and system. for instance, slow heavy cargo hauling can require more than that, even when kept to 15-20mph, depending on terrain. or to accelerate quickly enough to make it across an intersection from a stop before the light completely cycles thru to the cross traffic, etc.

 

[DogDipstick]

https://www.youtube.com/watch?v=xtZpmyOLfFQ

even professional superbike riders.

hahahaha yup.
Whenever someone trashes Simon Cowell for not being able to handle a " wimpy little electric bike " I always mention he is not the only one. Then I show/link that vid. lol. Guy is great, ( does alot with steam, and old boats, so there is a kind of 'personal connection" with me and what I do alot of... steamboots) ... and yea must take at least a little skill to transverse the Isle o Mann at an average of 130mph and a peak of over 220mph.... Lol. Whump, right on his butt. Going to the Isle of Mann to spectate has always been a dream for me,. Some day I'll hear those bikes. My ebike will pull up a front wheel around a turn, going full bore 35mph like a good roadracer, all tucked and knee out.. Lol... if you are not careful... Unlike my CBR 600... didnt really have the " catch you unprepared torque".... but... my ZX9 and 10r did. Lol tork. Laugh all day tork. Careful with that throttle tork.

I do love the silence of a good DD hub motor though. You can creep.. soooo quietly.

 

[E-HP]

Guy is great, ( does alot with steam, and old boats, so there is a kind of 'personal connection" with me and what I do alot of... steamboots) ... and yea must take at least a little skill to transverse the Isle o Mann at an average of 130mph and a peak of over 220mph.... Lol. Whump, right on his butt. Going to the Isle of Mann to spectate has always been a dream for me,. Some day I'll hear those bikes.

I did that the other day and it was pretty embarrassing, even though I didn't know if anyone saw it. I rode to the bottom of a hill, turned around to go back up, but accidentally started uphill and pedaled; a second later I'm on my butt. Bruised left knee, skinned right shin, and a yellowish bruise from knee to ankle, so there must have been some impact. I looked around and didn't see anyone around, but still felt dumb.
A buddy and me have been planning a trip to the Isle of Mann for about 40 years now, but I think it's about time to shoot for a firm date, while we can still get around. :wink:

 

[DogDipstick]

My conclusion is that if the temps are rising to melting levels, the external temp measurement probably won't rise quickly enough to prevent meltdown. The external temp may correlate with the internal temp, if kept at a steady state for a long enough period.

Hubsinks, mon . Hubsinks. They "wick" the heat away... but yea everything you say is certainly true. Temps IN the motor can raise to such a level of detriment quicker than the external shell assy can wick it out and transfer it away. However, hubsinks will get the shell closer to ambient, and allow for a greater transfer or heat entropy. A band aid, but they did do wonders for my little hub. Made it survive a 3.3kW controller, when before the hub sinks, my 1000w motor was burning up ( blackening on the stator windings). Now I can run it all day. It is one of the " sweet spots" that the hubsinks directly affect. Heat soaked magnets. Right next to the (hot) windings.