Motor reaching 90°C, go 10S?

P

Pedrodemio

100 W
Joined
Jun 30, 2015
Messages
115
Location
Brazil
Hello guys

For the first time i did my usual commute to test the board, on the last 100m i have a pretty step incline, i didn't measure yet, but probably 12%, when i arrived i got 90°C on the winding and 60°C on the outer carcass, this was maybe a minute after the climb, i supposed it go much hotter

My setup:
-Torqueboard 170 Kv motor
-50/28 gearing - 1.78
-6s 22.2V
-80mm Wheels

I'ts geared for 29 km/h

What can i do? VESC is on the way, i could probably limit the motor current, but i think i wouldn't be capable of climbing that last section. If there are no other way going 10S wold solve it because of I^2R relation? for now i would like to avoid buying more batteries because the dollar value here in Brazil is pretty bad

Thanks
 
Hopefully torque will chime in. He's been telling us all for a while that a higher KV (edit - i think he recommends 230-260kv) motor works better for hill climbing...

Single motor setup? How much do you weigh?

If you need to stick to a single motor, perhaps a 63mm vs 50mm would work better as well? I know the additional surface area helps with cooling!
 
I'm no expert but You are geared for speed not Torque . Change small gear for a 20T (higher gear ratio1:2.5) and go up to 9s(32.4v).

You will have about the same top speed but climb better.
 
I would recommend higher kv, i did a hill similar to that incline and my motor got pretty hot. So torques recommended higher kv (230kv) and i havent been disappointed yet!

plus the gearing you got right now puts a lot stress on the motor especially when going up hill. try a shorter gear ratio may help with your hill though, plus if you go higher kv you can get a shorter gear ratio and still have top end depending on your voltage setup. on 12s with 44t to 16t gear ratio on the 230kv motor i can 30+ easily.
 
Error speaks!

I_am_Error.png
 
Higher KV.. Too low KV and you lose momentum going up an incline. Once you lose momentum, it's hard for the motors to gain momentum because of the low KV.. Just my 2 cents.. I don't know actually what happens (I'm not an engineer :)).

I've been riding 63mm 230KV and the same hill which I use to struggle with the 170KV. The 230KV climbs up a 18% incline like butter. I've even throttled my settings lower since 230KV has a higher RPM and less rolling resistance.

The lower KV IMO provides no benefit..

People are enjoying the higher KV also.. Higher top speeds 25-27mph on a single motor. It just makes the ride so much smoother. Low KV it just feels it's lame.. I still don't know how it increases torque when my start-up is much faster on higher KV. I guess technically it does but in practice it's slightly different.
 
Going from 6s to 10s will do nothing to reduce motor heating.
 
torqueboards said:
Higher KV.. Too low KV and you lose momentum going up an incline. Once you lose momentum, it's hard for the motors to gain momentum because of the low KV.. Just my 2 cents.. I don't know actually what happens (I'm not an engineer :)).

I've been riding 63mm 230KV and the same hill which I use to struggle with the 170KV. The 230KV climbs up a 18% incline like butter. I've even throttled my settings lower since 230KV has a higher RPM and less rolling resistance.

The lower KV IMO provides no benefit..

People are enjoying the higher KV also.. Higher top speeds 25-27mph on a single motor. It just makes the ride so much smoother. Low KV it just feels it's lame.. I still don't know how it increases torque when my start-up is much faster on higher KV. I guess technically it does but in practice it's slightly different.
Click to expand...

Error said:
I would recommend higher kv, i did a hill similar to that incline and my motor got pretty hot. So torques recommended higher kv (230kv) and i havent been disappointed yet!

plus the gearing you got right now puts a lot stress on the motor especially when going up hill. try a shorter gear ratio may help with your hill though, plus if you go higher kv you can get a shorter gear ratio and still have top end depending on your voltage setup. on 12s with 44t to 16t gear ratio on the 230kv motor i can 30+ easily.
Click to expand...

So to make this right

-go 230Kv
-lower increase gear ratio to something like 50/22 = 2.27

and just increasing the gear ratio and going 10s would have no effect?

Torque, when your holiday sale ends? and the hole spacing on your 230Kv motor is the same as in the 170?

liveforphysics said:
Going from 6s to 10s will do nothing to reduce motor heating.
Click to expand...

So whats the advantage of going 10s? if you up the voltage the current will drop, and assuming the same power to climb a hill at the same speed, wouldn't the heat on the motor be lower because the square relation?
 
Hi

My 2 Cents
I have just replaced a 5065mm 270KV motor with a 6374 170KV Motor for exactly the reason you mention - the 50mm was getting really hot on inclines.
Now I do not want to spark any High/Low KV discussion here I am just saying how it goes for me.
I am about 90kg as I stand on the board and am no racer. I am not interested in top speed, all I want is to be able to go up any hill without crawling along or stressing the motor.
I am therefore more geared for torque than speed and run on 8S batteries and 97mm wheels.
There are two rather long steep hills in my area that I regularly commute, and here the 50mm motor slowed right down and therefore stressed the motor -actually killed one motor - no more magic smoke.
The 63mm motor pulls me up the hills - and I do not give full throttle due to me being a whussy and already going fast enough. The motor is warm at the top, nowhere near hot.
For me, and for others it will always be different, I am more than happy with the 63mm 170KV motor. It may be to slow for some but hell it feels like it can pull a train.

I am about to build a dual 50mm 270KV to see how that goes. Let you know once I eventually get my VESCs.
Probably be far to fast for me but I am looking forward to seeing how it does on hills. (And what range I am going to get out of 8S 8Ah)

Cheers
WeeCh
 
I'd go 230KV IMO. You can go a bit higher but gearing ratio would probably be less but 12T is a bit slim as far as teeth intact.

I'm using 2x 230KV, 16/36 on 10S/12S but I really moved my settings almost to the lowest settings but it works the best for my use climbing up hills. I climb up hills like butter. I lower it because I don't need or want the top speed -- too fast.

16/36 is 1:2.25.

Holiday sale will go until first week of January.

I think for 10S, your amp output will drop but because the KV is much lower it doesn't help much. You'll still have the same problem. Not sure on the technical knowledge though.

Changing to 63mm and 230KV will do much more than switching gearing and 10S. Although, that would work too. You would need a much closer gearing ratio though to 1. 18/36 or 20/36 or somewhere in that range.

The hole spacing for the 230KV is both standard 50mm and 63mm mounting holes.

I'm not much of a speed demon either but I love climbing hills and they are easier going slightly faster with more KV than less KV. The hills are 18% to 25% on average. I'm about 190 lbs with my backpack.
 
Pedrodemio said:
liveforphysics said:
Going from 6s to 10s will do nothing to reduce motor heating.
Click to expand...

So whats the advantage of going 10s? if you up the voltage the current will drop, and assuming the same power to climb a hill at the same speed, wouldn't the heat on the motor be lower because the square relation?
Click to expand...


Read:

https://endless-sphere.com/forums/viewtopic.php?f=2&t=74934
 
I have dual 200kv 50 series TB motors on 12/36 and 90mm wheels. When I went from 8s to 10s, the higher voltage allowed me to hit and climb the hills around my house with significantly more speed and thus use less power. Although the motors rarely get warm my peak power on one particular section went from a consistent 2kw to 1.5kw and I am now climbing significantly faster. It is all about getting the motor into the sweet spot. As you have learned there is a negative feedback loop where if you do not have enough power or gearing you are going to lug the motor and be out of the efficiency range where most of the energy you are using goes to just heating the coils vs spinning the motor!
 
It's a bit like edison vs Tesla with their transmission line voltages, Low voltage, high current dc moves slow through a circuit creating more heat needing large conductors while an ac signal with higher voltage and lower current creates less heat so smaller conductors can be used, with a motor general rule of thumb is higher the voltage more efficient it is, Your ESC uses pulse width modulation converting DC a constant straight line voltage (old fashion single phase brushed motor) to a wave pattern firing three phases 120 degrees apart so by raising the voltage of your motor to its specified limit it will create less heat for the same speed and load, but with increased voltage comes a new top speed a faster speed and same load will increase the temp so gear down a bit higher the voltage same speed less load on amps at a higher voltage means less temp simple as that.
Dc on an ossilacope looks like a heartbeat flatlining
AC on an ossilacope looks very much alive :)
 
and just increasing the gear ratio and going 10s would have no effect?
Click to expand...

If you go 10s AND increase the gear ratio it will help. Increasing the gear ration is what will make the difference. If you are going to use the VESC I recommend keeping the 170kv motor, changing the gear ratio and increasing the voltage. If you keep using 6s, change the motor gearing and increase the motor kv the motor will be fine, but the VESC will get too warm and limit the output power to the point where you won't be able to climb the hill at all. Buying more cells is better than buying a new motor anyway since you get more range that way.
 
Pedrodemio said:
Hello guys

For the first time i did my usual commute to test the board, on the last 100m i have a pretty step incline, i didn't measure yet, but probably 12%, when i arrived i got 90°C on the winding and 60°C on the outer carcass, this was maybe a minute after the climb, i supposed it go much hotter

My setup:
-Torqueboard 170 Kv motor
-50/28 gearing - 1.78
-6s 22.2V
-80mm Wheels

I'ts geared for 29 km/h

What can i do? VESC is on the way, i could probably limit the motor current, but i think i wouldn't be capable of climbing that last section. If there are no other way going 10S wold solve it because of I^2R relation? for now i would like to avoid buying more batteries because the dollar value here in Brazil is pretty bad

Thanks
Click to expand...


Why don't you try gearing down further, since you don't want to buy anything too costly. I think you should be able to solve your problem with gearing.

Overheating is a cascading failure, heat brings about more heat... If you gear down 15 or 20%, that may solve the problem completely at least for your length of hill.
 
If you want to keep the top speed, or surpass it, consider 12 S.



170kv is really better for 12s... Ideal Kv Motor for 6S should be around 380, from a revolution and efficiency view.



http://vedder.se/2014/10/chosing-the-right-bldc-motor-and-battery-setup-for-an-electric-skateboard/
 

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NyOliver said:
If you want to keep the top speed, or surpass it, consider 12 S.



170kv is really better for 12s... Ideal Kv Motor for 6S should be around 380, from a revolution and efficiency view.
Click to expand...
NyOliver said:
Why don't you try gearing down further, since you don't want to buy anything too costly. I think you should be able to solve your problem with gearing.

Overheating is a cascading failure, heat brings about more heat... If you gear down 15 or 20%, that may solve the problem completely at least for your length of hill.
Click to expand...

I will see with a friend if i can get some lipo's to test 10S and 12S

vedder said:
and just increasing the gear ratio and going 10s would have no effect?
Click to expand...

If you go 10s AND increase the gear ratio it will help. Increasing the gear ration is what will make the difference. If you are going to use the VESC I recommend keeping the 170kv motor, changing the gear ratio and increasing the voltage. If you keep using 6s, change the motor gearing and increase the motor kv the motor will be fine, but the VESC will get too warm and limit the output power to the point where you won't be able to climb the hill at all. Buying more cells is better than buying a new motor anyway since you get more range that way.
Click to expand...

Good to hear that, i already bought torque's 230Kv motor, but will test that first and return the order in case i'm satisfied

And as for the gearing i will be ordering a 18 tooth pulley (2,77 gear ratio), this way i get the above the 30 km/h with most of the discharge and go 10s

ecycler said:
I have dual 200kv 50 series TB motors on 12/36 and 90mm wheels. When I went from 8s to 10s, the higher voltage allowed me to hit and climb the hills around my house with significantly more speed and thus use less power. Although the motors rarely get warm my peak power on one particular section went from a consistent 2kw to 1.5kw and I am now climbing significantly faster. It is all about getting the motor into the sweet spot. As you have learned there is a negative feedback loop where if you do not have enough power or gearing you are going to lug the motor and be out of the efficiency range where most of the energy you are using goes to just heating the coils vs spinning the motor!
Click to expand...

This looks promising

liveforphysics said:
Read:

https://endless-sphere.com/forums/viewtopic.php?f=2&t=74934
Click to expand...

Now makes sense
 
U don't have to listen to me but all I will say is more heat u create less distance u can travel and more losses occurred very inefficient, don't just randomly stir a witches coldren till u pop something use some math and get it all singing to the same tune. The manufacturer goes through these troubles so you don't have.
 
Ianhill said:
U don't have to listen to me but all I will say is more heat u create less distance u can travel and more losses occurred very inefficient, don't just randomly stir a witches coldren till u pop something use some math and get it all singing to the same tune. The manufacturer goes through these troubles so you don't have.
Click to expand...

But isn't raising the voltage and gearing down whats you sugested? I forgot to quote you, the reply i gave to vedderwas suposed to you to
 
I think you are on the right path.

Step 1. Lower gearing and higher voltage.
Step 2. Higher KV motor if the previous cheaper tweaks did suit you.
 
ecycler said:
I think you are on the right path.

Step 1. Lower gearing and higher voltage.
Step 2. Higher KV motor if the previous cheaper tweaks did suit you.
Click to expand...

Probably going to do both, if i have to pay taxes for the 230Kv it's not worth returning, and in the future i plan to go dual hubs, and 63mm would do better in that, i already have one designed using the estator and rotor of my 170Kv motor, but i doubt it could climb well

Today i measured the hill, a modest 9%, só this is a gearing problem

105adld.jpg


2gyacue.jpg


3025cfd.jpg
 
Update

i'm with VESC for some time, limiting the current did nothing to prevent the overheating, as expected, but today i tested with the 230KV motor, awesome, still using the 50/28 gearing since i was not able to order the pulley anywhere, apparently is is way cooler, as soon as possible i will do the same route and measure winding temps in the end
As some of you might have seen i had little problem with my radio 2 weeks ago and crashed on the ground, superficial but extensive scratches, today was the first day ridding and need to gather courage again to fully test it, and by the way, the brakes did improve a lot, with the same current settings, i will need to tame it down or i will meet the pavement again soon

I can say that with the right gearing and 10S no hill will stop this board :D
 
Didn't see your post. How did you go down?
 
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