Revolt 120 pro eTrial overheating problem

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
User avatar
recumpence
100 GW
100 GW
Posts: 5356
Joined: Apr 19, 2008 8:33 am
Location: On Earth right now. That can change at any time, though..........

Re: Revolt 120 pro eTrial overheating problem

Post by recumpence » Apr 27, 2017 2:14 pm

Remember, heat is waste energy not providing work. The issue with these motors is inefficiency. I run far smaller motors at higher power levels without heat problems at all.

I was excited about the Revolt motors when they first came out. But, they are proving inefficient and unreliable.

Matt
Last edited by recumpence on May 01, 2017 6:26 am, edited 1 time in total.
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?

larsb
1 kW
1 kW
Posts: 306
Joined: Dec 10, 2014 5:12 am
Location: Gothenburg, Sweden

Re: Revolt 120 pro eTrial overheating problem

Post by larsb » May 01, 2017 12:46 am

What's your favourite motor in the 5kw range recumpence?
Both DD and mid drive options

jonnydrive
10 W
10 W
Posts: 95
Joined: May 11, 2015 7:16 am
Location: Italy

Re: Revolt 120 pro eTrial overheating problem

Post by jonnydrive » Jun 17, 2017 5:30 am

Hi guys,
finally I am able to update this post with my new experience with the E-trial.
I have been stuck with the engine problems (unresolved for now) that take me a lot of wasted time (thanks revolt!)

Here my e-trial in a today version

Image

before going in to the details, a very big thanks to all guys that helped me to debug and understand the problem during my first e-trial build.

After painted the frame and made a new support for the original seat and focused my attention on the engine.

To reduce overheating problem I machined a new rear sprocket of 70 Tooth (the maximum size for my CNC machine). I made it with Solidworks, I am totally nubby but I share with you the project.
NOTE: If you want machine a sporcket using my project please double check it before!

http://www.cerberotech.com/etrial/Coron ... o_3.SLDPRT

I put inside the project some parameter so you can change the tooth numbers without loose the correct tooth/sporcket size.
I used a 8 mm aluminium plate with a 420 chain (I need two of them).

The machining process required about 30 ours with a non-professional CNC machine
Image

The result, assembled on the wheel, is in the following image
Image

With a reduction of 13:70 the maximum speed is reduced to a granny speed in a trike (not electrified) ! I think that I can reach more or less about 30/35 Km/h (in a blink of eyes). In a offroad ride on mountains this speed is enough to give you a lot of adrenaline!

Another upgrade made is an active cooling system made with a barbecue fan. As you can see in the pictures on the opposite side of the chain I fixed the fan on a alloy plate.

Image

Unfortunately these settings aren't enough to avoid the overeating. During a long slope the fan do not provide sufficient air flow to keep the engine at low temperature ( a lot of power is wasted).

But I confirm that there is no way that Revolt 120 pro is able to keep 6kw of constant power. At least my engine. In previous post I made a few test to identify if there is some problem with the hall sensors but all test suggest me that there is nothing wrong with it.

The only way to move forward is to start to play with the Kelly controller settings reducing the phase and battery current. In this weekend I will made a ride to identify the correct settings to avoid overheating.

jonnydrive
10 W
10 W
Posts: 95
Joined: May 11, 2015 7:16 am
Location: Italy

Re: Revolt 120 pro eTrial overheating problem

Post by jonnydrive » Jun 18, 2017 4:32 am

Ok,
I try a lot of combination of Kelly Controller parameter (my controller is 300A max and 120A continuous)
With this one I got a good feel during an enduro ride, the throttle is very responsive and the torque is great.
For me enduro ride means good speed in single track on woods, some rocks to overcome but basically on flat or on slight slope.
A trial ride means single track at low speed with a lot of rocks and technical steps also with a high elevation

Image
I tried to limit the phase current but it provides a significant impact on performances.
I am not sure what 33% means: in a forum someone identify a relation of 0.7 between phase current and battery current.
let's do the math: 300A max phase current * 0,7 = 210A is the peak of current drained form the batteries (in my test I saw maximum of 150A but I was on flat road)
33% of 210A is 70A.

With those parameter the engine work at 62Volt * 70A = 4Kwatt. In a today enduro ride I found it enough to have a lot of fun.
However the engine work at 120°C using an active fan.

It seems that this engine is able to provide a good torque at high speed but it waste tons of energy at low rpm. During the tests I tried also this settings 30% phase current and 30% battery, the motorcycle get stuck but the engine still overheat trying to move the vehicle forward.

I also played with the esoteric PID parameter to have a rapid gas with a very good torque as soon you turn the throttle on, With the following I am able to overtake obstacle of 30 cm easily as a real trial-bike.

Image

jonnydrive
10 W
10 W
Posts: 95
Joined: May 11, 2015 7:16 am
Location: Italy

Re: Revolt 120 pro eTrial overheating problem

Post by jonnydrive » Nov 03, 2017 5:50 am

After playing a lot with active cooling system, including air wind turbine (broken at the second ride test), I moved my effort trying to reduce the engine stress during low speed ride.

The only way I found without replace the motor with a big and better quality ones was to re-use the motor gearbox.

What I have done:
- separate the gearbox from the chamber, quite easy with a good miter saw
- remove the clutch and adapt the shaft to fit a cog
- seal the gearbox (there are same holes thru the carter between the gearbox and the clutch units) with metal sealant
- place lithium grease instead of oil (ball bearings do not have the needles) and close the gearbox

the most complicated thing was fit the gearbox in to the frame, I adapted the bike frame by cutting one side and building a custom frame to fix the motor on the bike (many welds have been made!)

here some pictures
Image

Image

Image

Image

The results are pretty good, with a gearbox the engine can spin at the right speed without wasting a lot of power and overheating. Driving the bike in Enduro/trial ride is comparable to a real trial bike with a lot of torque available.
There is no need to change gear often, during hard slope 2° gear is enough to have a good speed without engine overheats also in a 1000mt elevation ride.

Without the gearbox, the ride was hard because a little movement of the throttle match with a significative increase of speed. If you need a fine drive maybe in a single track with obstacles there is not the best. The gearbox resolve this issue making the ride easy.

Drum
100 W
100 W
Posts: 167
Joined: Dec 29, 2013 1:20 pm
Location: Otaki New Zealand

Re: Revolt 120 pro eTrial overheating problem

Post by Drum » Nov 03, 2017 3:58 pm

It's great to see that you have got the bike going well. It is a shame that it took so much work, but you got there in the end.

The gearbox adds weight, complication and losses, but allows the motor to work in the high rev / low current regime most of the time.

Good work, hope you get a lot of enjoyment out of the bike after all the frustration and hard work.
Dave

User avatar
neptronix
100 GW
100 GW
Posts: 13097
Joined: Jun 15, 2010 5:56 pm
Location: People's republic of Petrolistan ( Utah, USA )
Contact:

Re: Revolt 120 pro eTrial overheating problem

Post by neptronix » Nov 21, 2017 11:16 pm

Looks like they were not honest about their power rating at all.
I recently read that they were switching from the old thick 0.5mm laminations to 0.35mm laminations.
This, plus spinning the motor to higher RPM could increase the continuous power quite a lot via gains in efficiency.

If you are stuck with this motor design as part of your frame, maybe a newer motor would help.
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

jonnydrive
10 W
10 W
Posts: 95
Joined: May 11, 2015 7:16 am
Location: Italy

Re: Revolt 120 pro eTrial overheating problem

Post by jonnydrive » Jan 19, 2018 9:38 am

Thanks for the info neptronix,

but too much trouble for me to stay with revolt motors, next bike will be around a bigger inrunner motor.

A guy is testing denzel D7500 (http://www.eastgem.net/d7500.html) that with a ridiculous price provides 10kw of power.... not bad at all!

https://endless-sphere.com/forums/viewt ... 0#p1352180

larsb
1 kW
1 kW
Posts: 306
Joined: Dec 10, 2014 5:12 am
Location: Gothenburg, Sweden

Re: Revolt 120 pro eTrial overheating problem

Post by larsb » Jan 26, 2018 2:35 am

I am seriously considering a gearbox, the most reliable option is to adapt an existing box - i'd like to see more in depth how you did it.

Do you think it's possible to show the gearbox adaptation in a separate thread? Think it'd be useful for many here going that route.

jonnydrive
10 W
10 W
Posts: 95
Joined: May 11, 2015 7:16 am
Location: Italy

Re: Revolt 120 pro eTrial overheating problem

Post by jonnydrive » Jan 30, 2018 6:40 am

Hi Larsb,
I will post some photos of my working on the gearbox if I can find them!

What I did:
  • Remove the clutch
  • Disassemble the motor
  • Separate the gearbox from the engine chamber using a saw. Pay attention to keep intact the gerabox section
  • Remove the unnecessary parts of the gearbox keeping the holders that fix the engine to the frame
  • Manual Mill the clutch shaft using a grinder enough to fit a regular rolling chain cog
Image
  • Engrave in the clutch a small section where to place the key
Image
  • Seal the gearbox. My engine had holes between the gearbox and the clutch, I sealed them with a liquid steel glue
  • Put grease or oil in the gearbox. It depends on how you are been able to seal che gearbox chamber and the ball bearing with related seals

jonnydrive
10 W
10 W
Posts: 95
Joined: May 11, 2015 7:16 am
Location: Italy

Re: Revolt 120 pro eTrial overheating problem

Post by jonnydrive » Feb 09, 2018 12:49 pm

Riding on the snow is very fun!
I am start thinking that gearbox is a real good choice for difficult terrain

Image

Image

Post Reply