MAC Motor 500W and Hot wires

[dodjob]

Hi there,
I'm curently testing a MAC motor for my new project. I wanted to know if anyone had issues with hot wires. I mean the three phases wich are coming from the controller to the motor. I'm not really sure of the temperature but they get REALLY hot. And I don't like to warm the planet (that's the only reason of course. Couldn't be that I'm a really shitty perfectionnist that doesn't like to lose any bit of the power I extract from my batteries ^^)
Anyway, does someone has replaced the wires for bigger ones? If yes, how big? Any modification to the Shaft? I know, I use a 12 Fet with 40Amps but I have read that some of you guys give them way more. How did you do that!!
Last little question. The motor is making some weird noise at the start, something resembling to hall-sensors-problems-noise but not so loud, you only feel it vibrating a little. It disapear then when the motor has get some Rpm. Is it normal?
Anyway, except this littles things theses motors rock. Damn the torque is reaaaallly good
Gruß,
H.

*edit*
I have them quite warm/hot at 30-35Amps constant.

 

[dogman dan]

Too much amps for that motor. Have fun till it melts. I wouldn't worry about the wires, they'll last longer than the motor.

30 amps spikes, then 20 should be fine, but those wires getting hot is a red flag warning that your windings are doing similarly.
In a way, the hot wire is helping you, not letting all 30 amps reach the motor. But you can easily upsize the wires from the axle to the controller, leaving only a short piece of the small wire, and cut resistance quite a bit.

It shouldn't be needed to replace the wires into the axle, unless you want to make vids like Live for Physics and Methods do. Plasma shots.

 

[neptronix]

Yup, i agree, much over 40 watts will turn it into a smoke machine

Mine gets well heated at 43 amps constant; it may seem just warm on the cover plate, it's much hotter inside due to the stator / magnets having some spacing between the cover plate.

The wires are only 16 ga like most hub motors.

If you have a 40amp controller you are probably pulling more like 50, have you checked with an amp measuring device? My bike is set to 30 amps but will pull up to 43 amps on hills

As for your noise at the beginning of acceleration, is it sorta like a shuddering/clanking sound?
If so, you need to up your phase amps a tad over the 2.5x rule, which has seemed to cure that for many MAC/BMC folks.. for example, my motor is set to 30/80 amps instead of 30/75 amps.

 

[dodjob]

Thanks a lot mates!!
This is really cool to get so much real experience from you!
I have a Cycle analyst. But when I've tested my motor the Rshunt was not settled (it was only set to 3.00 m0hm to avoid any cutoff from the CA). I have set it today to 2.0 mOhm which seems to be correct. Any hint on your side? I have use my Medusa power analyzer and this amount seems to be ok.
Concerning the wires I will try to put bigger wires, and only let about 10cm of "little" wires. I didn't know that the MAC had only 16G windings. That make sense. I will make more test tomorrow and check the motor temperature. My target is really not to method-plasma my motor ^^
Finally for the programming, I have an eb212-as-1, are the port for programming the same as on the Lyens 12FET? Does someone knows where/how can I check it?
Owwh I have a last question. This concern the wiring. I have tried to see if this "shuddering/clanking" was the same on another motor. What has really surprised me is that the order of the 3 phases wires (green/blue/yellow) had to be changed to get the motor turn. ' is this "normal"? (and yes the shuddering was the same)
Thanks again for your time and precious infos. Daaaamn I love this forum!
Gruß,
H.

 

[wineboyrider]

I dump around 20 amps continuos at 36v lifepo4 into my BMC (similar to Mac) and it goes 27-29mph! So around 1200 -13000 watts. I don't have CA on my bike, but I do have a turnigy watt meter. Nicobie was telling me at the death race that he was putting 3000 watts into his bmc and it did great for a while. Eventuallythe gears will go out, but Lyen and others sell better gears that last longer. I might try and get a different controller and dump 3000 watts into mine for the death race, but then again they don't call it the death race for nothing. Until then I'll just use it at 36v lifepo or 12s lipo...;/
:wink: :wink:

 

[wineboyrider]

Owwh I have a last question. This concern the wiring. I have tried to see if this "shuddering/clanking" was the same on another motor. What has really surprised me is that the order of the 3 phases wires (green/blue/yellow) had to be changed to get the motor turn. ' is this "normal"? (and yes the shuddering was the same)

I have the same problem with my BMC at higher voltages on Lyens 9fet controller. It has something to do with the clutch and the timing of the controller? Nicobie was also telling me he had a similar problem and fixed by using a crystalyte analog controller?
These motors seem to run weird at voltages higher than 48v, but damn they are fast and torquey for the voltage you pump into them...
I don't want to run it higher than that right now, but I might for the death race.... :? :? :?

 

[dodjob]

Thanks Wineboyrider
I will try first the trick with the phase amps modification. With the actual setup I think that I pull out about 60 AMps out of the Cells (they are also damn hot . But.. mmm this motor pull hell. I looove It. I have also a 1000W version that I will start to test soon. This time on a 36V60 Amps setting.
The actual 500W motor with 48V headway ride about 50Km/h on flat/no pedaling and 75Km/h hot off the charger with "no-load". I think my ride will be funny downhill ^^
Gruß,
H.

 

[auraslip]

When I was researching to buy a new hub motor, I read through the whole lot of mac/bmc threads. Almost everyone running decent power melted their phase cables. The stock wires were WAYYY to thin supposedly. The only solution they found was to install 10 gauge phase wire as close to the motor as possible. Huge 6mm bullet connects could help sink some heat as well. See this thread.

Also, upgrading phase wires is a great upgrade. You WILL notice an increase in power. Check out my lil' power loss through wire resistance calculator.

With 16 gauge wire @ 35 amps you're wasting 200 watts worse case scenario and 80 watts best case scenario! And it's all turning to heat....

 

[neptronix]

10 gauge would be great, but would allow you to run the motor far beyond what the windings and mechanicals are able to handle.

What becomes a problem at higher power:

1. Keyway destruction ( i think mark_a_w mentioned this )
2. Clutch destruction ( various members )
3. Gears ... i have heard of people going through green gears but i don't remember their names..
4. Windings / magnets; there is about 1/2 ( or less ) of the copper/magnets as a comparable DD motor so the motor can only handle so much.. You can't push it like a 9C or Clyte! I suppose it is spinning faster... but.. still!!

I think the thin wires are a good thing. They prevent you from doing things that are more catastrophic.
I really think, for DD hub-esque high wattage, that the BMC and MAC motors as they are, are dead ends.

That being said, i am real happy with this motor at ~2500 watt peaks. Don't need to go faster than 34-37mph on city streets.

Cell_man has mentioned that MAC is considering making a bigger motor that can handle twice the power.

 

[auraslip]

I agree, replacing the stock cables isn't going to magically make these motors capable of handling more power. Definitely should tune the power down.

Still though... 16 gauge cable.... that's like for setups running at 15 amps. What a waste of battery power on a decent ebike

 

[neptronix]

Yeah, but ebikekit/ampedbikes/MXUS 9C knockoff motors have 16gauge too. So do a lot of smaller motors.

A rather unfortunate standard!

 

[dogman dan]

Same thing applies to dd motors such as 9c. About 2000 watts gives you a decent length ride before meltdown. Playing with 3000 watts or more is just playing with fire. It works great! but for lots shorter time periods. I thought I had my death race motor dialed in, but it smoked at 11 laps in a 12 lap race.

So what wattage you can get away with depends a LOT on the duration of ride you need. For a 1/4 mile, I wouldn't hesitate to do 5000 watts, but for 15 miles, a 2000 watt limit makes some sense.

 

[wineboyrider]

I have a 9c, mini-motor and BMC hub motors. And the BMC is by far my favorite! The 9c is durable and will probably last longer, but you can go faster on lower voltages with this thing. As a commuter setup I would probably not run it higher than 15s lipo, because it would be to damn fast for a bicycle frame IMHO.

 

[toaroa]

Meanwhile...

My MAC keeps chugging along happily and running cool as (probably because I have a 36v battery and a 20A controller which almost never gets beyond 14A). It sits on a max speed of about 34km/hr which clearly isn't fast enough for some, but I certainly appreciate its reliability (phase wires never get hot, gears never deform, etc.)

 

[dodjob]

ok Guys,
Now I know why it's hot:

but after a "little" modification of the wires to AWG 4 (sorry this was all I had under the hand) the wires remain cold. The motor not, but I was warned. This thing pushes Hell ^^
Gruß,
H.

 

[wineboyrider]

Meanwhile...

My MAC keeps chugging along happily and running cool as (probably because I have a 36v battery and a 20A controller which almost never gets beyond 14A). It sits on a max speed of about 34km/hr which clearly isn't fast enough for some, but I certainly appreciate its reliability (phase wires never get hot, gears never deform, etc.)

I have a lyens 9fet controller 36v battery and I get a max speed of 30mph! It usually pulls 20 amps and 38-39 peak. :|

 

[www.recumbents.com]

Replacing the phase wires isn't going to give you higher peak power, but it will make the system more efficient. Yes, you need to know what your motor can handle and not just wang the throttle off the line or try to climb a mountain. I replaced the phase wires on my BMC 600 up to about 4" from the motor and gained a couple MPH on the top end.

-Warren.

 

[dodjob]

yop, that's something I've noticed. I can top about 53Km/h now.
My target was really to make the things more efficient even if I know that when I throw 70 amps in the Motor things are far away to be "efficient" Anyway.
Meeen! the BMC's motors have a really higher Kv! 30Mph with 36V batteries this looks like the specs of a 1000W Mac motor.
Gruß,
H.

 

[wineboyrider]

30Mph with 36V batteries this looks like the specs of a 1000W Mac motor.
Gruß,
H.

Jawohl! You have done your homework young padowan. Mine is more of a speed motor and the other is a hill climber...correct?


Wie ist das Wetter in Deutschland?

 

[dodjob]

Achsoooo
Der Jung padawan freut sich!
The weather in Germany is.. how should I put this.. Incredibly beautiful .
We had the best weather (in therm of sun quantity) since the weather has started to be been recorded in Germany. And this for the last two month. I drive EVERY DAY with my cruiser and started the last two day with the actual custom I'm curently building.
I still have to make the two covers (verkleidung) in vacuum forming and I put some pictures online ^^
Damn this beast is the best yeaaaaaaah How is the weather in New mexico?
Viele Grüße,
H.

 

[wineboyrider]

Sunny hot and very windy! That's normal this time of year, but it's a dry heat hehehe. Grapes aren't doing so good this year, because we had a cold winter event it was below -16 F for 3 days at night and a lot of the vines are coming up from the gound
Bike riding is almost year round here, even when it's hot when you get moving the sweat keeps you cool.

 

[toaroa]

my point (lost, apparently) is that these motors are not designed for some of the speeds which folk want to achieve with them and they are certainly not designed for high amps. Keep to 36v with a max of 20A and they just go and go and go. What does my peak draw of 14A and max hot of the charger 40v (lifepo4) add up to? .... usually, nothing higher than the 500W of the title; most often less. Unless you've got some serious reprogramming happening (making the extra capacity in the controller a wasted asset), it aint gonna last long with a 30+amp controller!

 

[whatever]

the other reason is that all these mac bmc/ ezee geared motors were originally designed as 250watt continuous motors, they aint designed for the powers you want to use, its a tiny hole in the axle, the topic has come up over and over again, over many years, some have managed to squeeze a slightly larger dia wire via the axle...........same problem over and over and over
Its hard to search old posts on this forum, but there is a wealth of info on this problem going way back

 

[neptronix]

I don't agree, i know people who run about 1000-2000 watts constant with thousands of miles of no issues..

 

[dodjob]

WOuldn't good to make some sticky thread of every motors?
I love this forum but we are too active ^^^. There is tons of infos on everything here. And real infos actually but it's sometime a pain in the A##! to reach the correct thread.
Anyway. I will conduct tomorrow some more test to see which Max amps setting is letting my "poor" MAC motor "cold" on top hill. I'm nevertheless not thinkig that it will be more than 1500W. But that's really enough
Gruß,
H.