Need some ideas so i wont burn my hub

[jrclown]

So I’m doing this mostly just to do it, because I don’t have another hub right now. I have a generic 750 W, 36 V rated front hub motor, and I built a microcontroller system to control a chain-driven rear motor. So the rear motor is on the T-side, and the hub motor is the rim-side. It’s a big, complex setup. When I’m done with it, I’ll post it just to show what I can do.
I’m going to be using a 48 V battery pack that can handle around 80 amps if needed, but I also have a 2 kW, 50-amp Farcy controller for the front hub motor. I know that if I try to run the 750 W 36 V hub hard, it’s probably going to overheat or melt. I’m just looking for some good suggestions on ways to keep it cool so I can use it temporarily until I get a new hub, which might be 3–4 months out.
This is just a practice build to show off what I can do for the business I’m starting. I know that upgrading the phase wires can help with heat dissipation. I was thinking about running 10 AWG up to the point where the wires enter the motor, but I’ll still need more help than that. I know it’s eventually going to overheat, but I don’t want it to melt on the first ride.

 

[jrclown]

So I’m doing this mostly just to do it, because I don’t have another hub right now. I have a generic 750 W, 36 V rated front hub motor, and I built a microcontroller system to control a chain-driven rear motor. So the rear motor is on the T-side, and the hub motor is the rim-side. It’s a big, complex setup. When I’m done with it, I’ll post it just to show what I can do.
I’m going to be using a 48 V battery pack that can handle around 80 amps if needed, but I also have a 2 kW, 50-amp Farcy controller for the front hub motor. I know that if I try to run the 750 W 36 V hub hard, it’s probably going to overheat or melt. I’m just looking for some good suggestions on ways to keep it cool so I can use it temporarily until I get a new hub, which might be 3–4 months out.
This is just a practice build to show off what I can do for the business I’m starting. I know that upgrading the phase wires can help with heat dissipation. I was thinking about running 10 AWG up to the point where the wires enter the motor, but I’ll still need more help than that. I know it’s eventually going to overheat, but I don’t want it to melt on the first ride.

Idc to take it apart so if I can do something to make it handle it lil better just point me in right direction thanx

 

[E-HP]

Idc to take it apart so if I can do something to make it handle it lil better just point me in right direction thanx

Fill it with ATF.

 

[jrclown]

Fill it with ATF.

Won't mess with hall or the magnits?

 

[neptronix]

Geared motors usually cannot take many multiples of their rated power like direct drives can.

I would run no more than 1500w peak on that front motor and i would also use a weak phase amp to battery amp ratio so that it doesn't have super strong torque off the line ( this is how you blow your geared motor's clutch )

As far as continuous power goes, i'd keep it to ~1000W because geared motors cannot shed heat well

10AWG is a waste on a 750w rated motor, maybe use 12GA at best

These are all general recommendations from a long term geared motor enjoyer. I don't know what motor you have so i cannot help with specifics.

ATF has a lot of odwnsides, search the forum for threads about oil / atf cooling motors. We got some good ones.

 

[E-HP]

Won't mess with hall or the magnits?

Definitive Tests on the Heating and Cooling of Hub Motors

Hey guys, so I've been meaning for a long, long time now to run a set of controlled lab experiments measuring the temperature rise of hub motors being subject to different load conditions. The main objective is to develop a more comprehensive 2nd order thermal model to incorporate into the...

endless-sphere.com

Justin uses ATF in some of his testing. The downside of ATF depends on the application, which you have not described clearly yet. As a hub motor heats and cools under normal use, that heat expands the air inside the motor, creating pressure. When it cools, it create vaccuum. When adding ATF, some will leak over time due to the internal pressure and lack of good sealing. It may not leak a lot, but in an ebike application, any leakage that gets on a disc rotor will screw up your braking. If your application doesn't use disc brakes, then you may be OK will a few drops leaking out here and there, and occasionally having to top it off.

I have no idea what "the rear motor is on the T-side" or "the hub motor is the rim-side" means.

 

[jrclown]

Definitive Tests on the Heating and Cooling of Hub Motors

Hey guys, so I've been meaning for a long, long time now to run a set of controlled lab experiments measuring the temperature rise of hub motors being subject to different load conditions. The main objective is to develop a more comprehensive 2nd order thermal model to incorporate into the...

endless-sphere.com

Justin uses ATF in some of his testing. The downside of ATF depends on the application, which you have not described clearly yet. As a hub motor heats and cools under normal use, that heat expands the air inside the motor, creating pressure. When it cools, it create vaccuum. When adding ATF, some will leak over time due to the internal pressure and lack of good sealing. It may not leak a lot, but in an ebike application, any leakage that gets on a disc rotor will screw up your braking. If your application doesn't use disc brakes, then you may be OK will a few drops leaking out here and there, and occasionally having to top it off.

I have no idea what "the rear motor is on the T-side" or "the hub motor is the rim-side" means.

I cant type for crap so I use Ai and it fixes shit up but I have a small 36v chain driven motor on the rear for the torque and the hub on the front i have a microcontroller that takes in throttle imput and I have it set up to only use the rear motor till reach 10 mph then it fades to front hub and a hill climb mode on it so they both work together when I go up a hill the microcontroller only takes and sends throttle imput and has learning logic for hill climb mode allso have password set for child mode only uses 1 motor and won't go over 10 mph and a limp mode all controlled by throttle imput has other stuff it dose aswell and I dont think that would work but I allso have disk breaks and im just not trying to melt the hub putting all that power to it till I get a better hub

 

[jrclown]

Geared motors usually cannot take many multiples of their rated power like direct drives can.

I would run no more than 1500w peak on that front motor and i would also use a weak phase amp to battery amp ratio so that it doesn't have super strong torque off the line ( this is how you blow your geared motor's clutch )

As far as continuous power goes, i'd keep it to ~1000W because geared motors cannot shed heat well

10AWG is a waste on a 750w rated motor, maybe use 12GA at best

These are all general recommendations from a long term geared motor enjoyer. I don't know what motor you have so i cannot help with specifics.

ATF has a lot of odwnsides, search the forum for threads about oil / atf cooling motors. We got some good ones.

Its the magnit with hall sensor i think its called direct but not geard its just a cheap ebike hub kit hub not a big deal if I blow it but just trying make it last till I get one that can handle what I have

 

[jrclown]

I am newish to ebikes so dont qote me on names of things I think I got my awnser tho ill limit it to 1kw or just be gentle with it till I get a knew hub lol then I can melt it thats going to be fun

 

[jrclown]

But after I get the firmware running smoth I'll post it working if u want to see it

 

[neptronix]

Its the magnit with hall sensor i think its called direct but not geard its just a cheap ebike hub kit hub not a big deal if I blow it but just trying make it last till I get one that can handle what I have

Hmm, pictures would be helpful

Also at this power level are you using two torque arms.. i hope so, otherwise you get to discover the hard way why you need them.
Do note that suspension forks can break at very high power ( >1000W? something like that ) from repetitive twisting ( aluminum/magnesium forks are not designed to handle these forces)

 

[jrclown]

I actually haven't been able to put it together yet I dont have them but everytime I started to work on my bike id get more battery repair or orders in and i blew my spot welder lol but I shouldn't have a spot welder prob anymore zues helped me out there but I do need to get them

 

[jrclown]

But i can send picks of the hub and chain driven on the rear not anything fancy this is a prea bud to make shure I can get logic and everything I need to make a bigger e dirtbike later with same set up and kind of a look what I can do type of thing give me a few ill drop the picks in

 

[jrclown]

Ignore the mess iv had to keep my daughter in the work room she been clingy cuz she sic but like I said nothing fancy

 

[neptronix]

Wish you used punctuation and line breaks when you typed :O

This looks like a geared motor, a DD hub would usually be bigger.
You can tell for sure because when spinning the wheel with your hand, one direction spins freely, the other has lots of resistance.

 

[jrclown]

I do battery work on side my main job is seasonal roofing and remodeling so like I said im new to the ebike thing im pretty tech savy and engineering comes easy so if I miss speek on something thats my bad and spelling and punctuation is not my strong suit so bare with me

 

[jrclown]

Wish you used punctuation and line breaks when you typed :O

This looks like a geared motor, a DD hub would usually be bigger.
You can tell for sure because when spinning the wheel with your hand, one direction spins freely, the other has lots of resistance.

Ya sorry I try to use Ai to fix that but it bucks up what Im trying to say ill start useing it again

 

[E-HP]

I cant type for crap so I use Ai and it fixes shit up but I have a small 36v chain driven motor on the rear for the torque and the hub on the front i have a microcontroller that takes in throttle imput and I have it set up to only use the rear motor till reach 10 mph then it fades to front hub and a hill climb mode on it so they both work together when I go up a hill the microcontroller only takes and sends throttle imput and has learning logic for hill climb mode allso have password set for child mode only uses 1 motor and won't go over 10 mph and a limp mode all controlled by throttle imput has other stuff it dose aswell and I dont think that would work but I allso have disk breaks and im just not trying to melt the hub putting all that power to it till I get a better hub

If it's a geared motor, which given your earlier description, seemed highly likely, then I'd just follow neptronix advice. However, based on your description above, your motor won't be subject to high torque off the line, since your control logic doesn't start the front motor until 10mph, so you might be able to push it a bit. However, looking at your pics, it's doesn't look like your typical geared hub either. Sort of shaped like a mini direct drive. Anyway, if you would be willing to open the motor, that would solve that riddle, and if it actually is direct drive,, then the cooling options are available (statorade, hub sinks).

 

[jrclown]

If it's a geared motor, which given your earlier description, seemed highly likely, then I'd just follow neptronix advice. However, based on your description above, your motor won't be subject to high torque off the line, since your control logic doesn't start the front motor until 10mph, so you might be able to push it a bit. However, looking at your pics, it's doesn't look like your typical geared hub either. Sort of shaped like a mini direct drive. Anyway, if you would be willing to open the motor, that would solve that riddle, and if it actually is direct drive,, then the cooling options are available (statorade, hub sinks).

I’ll take it apart tomorrow and follow up with you. I was hoping that, because of the logic, I could get away with it—but thank you. I’ll follow up tomorrow. I’ll do it before my spot welder replacement arrives.

 

[neptronix]

It's much easier to just spin it backwards/forwards to find out

 

[jrclown]

I honestly can’t tell that way. The only reference I have is from the caliper, where I need to true my rim.

 

[jrclown]

I honestly can’t tell that way. The only reference I have is from the caliper, where I need to true my rim.

 

[jrclown]

I gusse i cant post video clip

 

[jrclown]

I gusse i cant post video clip

It dont feel like a magnet is pulling it but it

 

[jrclown]

Its gears I played my vid of me riding on it I do believe its geard