MAC motor controller?

A while back I received a MAC motor and controller in trade for some fabrication work. Now I have a friend who could use an e-bike for rehabilitation, and I want to use the motor for that.

My concern is that the controller that was included with the motor is 48V, 40A. I thought MAC motors were intended for used with 25A controllers. Is this correct? I'd rather not put the motor at risk of damage, and I'd also rather not buy a 40A capable battery if I don't have to.

What's a good controller for MAC? KT, or is there something more compatible?

The wiring connectors are a mess, and my intention is to redo them, so it doesn't matter so much what the controller comes with. Also, I have no idea the kV of the motor, or its gear reduction, so I'd like to be able to run the controller on 36V or 48V as necessary to set the road speed in a good range.

Any insights are appreciated.

Open up the controller and see if it has more than one shunt.

If there are four, cut two and now it's a 20A controller.

Probably it will have two or three shunts. Cutting one should take it down to around 27-28A max.

Then you don't have to deal with finding a controller that works with it (potential eRPM issues).

It's also possible the controller is already programmed for a lower current limit than what it's labelled as.

Thanks for this. I'll snoop inside the controller I've got and see if it's straightforward. It's pretty big, so there is another benefit to finding a smaller one. But cost savings and known compatibility are both worthy goals.

I seem to recall that the older MAC motors had an issue with the hall sensor placement that gives it an inherent timing advance. The controllers made for these motors dealt with the advance somehow. Newer versions of the MAC had more standard hall placement that works with most controllers.

fechter said:

I seem to recall that the older MAC motors had an issue with the hall sensor placement that gives it an inherent timing advance. The controllers made for these motors dealt with the advance somehow.

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Good to know. There's another incentive to keep the old controller.

A 40 Amp max. controller is not necessarily too much for a Mac.
Bad things like over-heating, melted wires or worse are bandied about, but the first thing to be considered, and the thing more likely to effect day to day riding, is how the controller engages the motor. A "hard-hitting" controller, like a 40 Amp Infineon, can result in "gear hammering"and a touchy throttle, creating a need to "tame the throttle", but older genarics and the newer "torque imitation" controllers are much softer starting.
As far as "over-heating" is concerned, so much of what might be anticipated is a function of the total system intergration of motor speed and whl. size.
This is a rough generalization, but too slow a motor speed can exacerbate motor heating, while too high a motor speed can exacerbate controller heating. In a sense, the "too low a speed motor/over-heating" problem is "self-correcting", so the "too high a motor speed", where the controller "tries to feed" the motor's "wants" with lot's of Amps, is probably more of a concern in this case.
I would say, if the Mac is not on the highest motor speed ranges, the supplied controller would be safe enough. After all, somebody used them together before.
I.M.O., a better motivation for up-grading the controller would be to take advantage of the many features that have been added in the last several years.
Having said that, the larger geared motors don't seem to have the selection that the "mini" geared motors do.
One way to go is the Infineon/Cycle Analyst route, ala Ebike CA or EM3ev, or....
look to the "torque imitation" sine waves from BMS Battery. Unfortunately, their line-up is rather dated and has never hit the 25 to 35 Amp range mark that well. BPM riders tend to go w/ the old skhool square-wave KU-93, the Torque imitation SO9P, or finaly, the sine wave S12S.
On my 2WD rear Ezee V1 motor, I run the Elife Bike 9-FET 20 Amper shunt-mod'ed gto 25 vAmps. A modern square wave, it is smooth and quiet w/ enough features for me, but at 25 Amps, the performance it provides is somewhat underwhelming. The popular KT sine waves they carry only go to 20 Amps(I have a new one w/ LCD-5 display, if anyone is interested).
If I were the Chalo, I might consider testing the controller he has now and if it works and is not too much of an antique, add a Cycle Analyst CA-SA to the mix. For a while, Ebike CA had the older versions of C.A.'s on sale.

amberwolf said:

Open up the controller and see if it has more than one shunt.

If there are four, cut two and now it's a 20A controller.

Click to expand...

Hacking shunts out of a programmable controller is a pretty brutal last resort -- not a first line of attack. Once you butcher the controller you no longer have calibration and the programming utility profiles will no longer apply. Working back to being able to program it is a PITA.

So - first see if it has a programming connector.
Look for a 5 pin female JST with yellow/red/black/green/white wires. If so, you can get a programming cable and set the phase current and battery current to whatever you like. MACs like a ratio of those to no more than about 2:1. This ratio is often misconfigured since DD like something about 2.5:1 and so that is a common default Infineon (Xie Chang) setup but not so good for the MAC. You can reduce the ratio still further to soften the getaway torque but retain the basic controller battery power limiting (i.e. reduce the phase amps).

If that's a programmable controller from EM3EV or Lyen, there's no telling how it's set up now and if you don't hack it, you can easily adjust it to your needs. If you do chose to hack it, there's no telling what you'll get.

Chalo said:

I have no idea the kV of the motor, or its gear reduction,

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The gear reduction is 5:1 but that's irrelevant. Put the thing on a truing stand, hook up the controller and run it flat out. You can measure the rpm and so will know the Kv and hence the wind - the most popular are 8T and 10T. From there you go to the ebikes.ca simulator and figure out what controller current and battery you need to do what you want. Not really any guesswork or on-the-road experimentation involved. Remember that regardless of the wind, all MACs have about the same hill-climbing power - the higher turn count motors will just have a lower top speed. So - since hill-climbing depends on torque (phase amps), it's the controller that determines that ability.

motomech said:

A 40 Amp max. controller is not necessarily too much for a Mac.
... the thing more likely to effect day to day riding, is how the controller engages the motor. A "hard-hitting" controller, like a 40 Amp Infineon, can result in "gear hammering"and a touchy throttle, creating a need to "tame the throttle",...

Click to expand...

This is spot on, although to be clear, it's the clutch not the gears that can be damaged. This is why EM3EV used to have caveats on the old site about using the 12FET on a MAC - their standard choice was a 9FET. The new site is tidied up and a lot of the info is gone or hard to find.

FWIW: I have a MAC10, 52V battery on one bike and ran an EM3EV 12FET on it programmed for 35A/74A. It was a wheelie machine until I installed CAV3, at which point it became easily drivable with soft getaways, etc. I have another bike with two 8T BMCs (MAC clones) run by 12 FET Lyens @ 66V. Same huge torque story - the CA3 lets me run the motors at 35A/74A each, but I could also program the controllers down to lower ratings and lose the CA.

So... I just dug this stuff out of storage and to my surprise, I got the details wrong.

First off, the motor is a BMC. I have no clue how that differs from a MAC, but that's what it is. Second, it's not a 40A controller, but 50A. Any different ideas based on this new information, or does all the previous advice still hold true?

I'm attaching photos below.

BMC and MAC are really the same. If you have a standard controller lying around, you might try it to check the hall timing. If the motor has the goofy hall placement, a normal controller will have abnormally high no-load current at full speed. Like it will be 5A instead of 1A.

Ok - pics were helpful.

As the label indicates, you have a BMC controller. This used be sold with BMC motors as a matched kit by HPC and Ebikes SF back in the day. You can find stuff on it in older ES posts. Here's one that should be helpful - see: https://endless-sphere.com/forums/viewtopic.php?f=31&t=11024&start=50#p227733





Historically, this was the only controller that could drive a BMC/MAC except for the old Xlyte analog controllers (which were super smooth!). Paul at EM3EV figured out how to get Infineon controllers to work and sold (and continues to sell) them with MACs. A couple of years later, Ed Lyen reverse engineered Paul's controller changes and incorporated it into his controllers so his Infineons also work fine. The BMC was too expensive and hard to get and fell into disuse even though it was made specifically for the motor. It's also not programmable, though it has a few strapping options.

The BMC, eZee, and MAC motors all started life from the very same design way back, but split into different suppliers. Because of the common heritage, they are very similar. Most importantly, the clutch/gear assemblies in these motors use the same shaft, keying, and outward dimensions and are interchangeable as an assembly. However, the component gears, clutch, etc cannot generally be swapped between units - you need to swap the whole gear cluster.

For you, that means that if there is a clutch issue, you can drop in an inexpensive MAC gear cluster from EM3EV. An equivalent BMC unit is impossible to locate and costs more than twice as much.

So - your motor is internally almost identical to a MAC but has only a single side cover and has shaft seals on the axles (see my Mundo build for info on bearing and seal numbers/replacement info). AFAIK, the BMCs always had wonky timing and draw about 5A unloaded. These have got 0.5mm lams and so are not quite as up to date as contemporary MACs from EM3EV with 0.35mm lams. Not a big issue.

So - although that's now a pretty obscure motor with virtually unobtainable replacement BMC parts, it's a great motor and all replaceable parts (clutch, gears, bearings, seals) can be easily sourced from contemporary non-BMC suppliers. It should have a very long service life.

Anyhow - that setup was pretty much the top of the line gear motor setup for its time. As I mentioned above, I have two similar BMCs on a bike running with Lyen controllers and they pull like mules with over 14000 miles on them (with the usual bearing replacements along the way). Your stuff should make a nice bike although the controller is physically kind of large.

That's great information! Thanks teklektik!

I had always heard BMC and MAC motors referred to as if they were interchangeable, but it's good to know the details. And it sounds like the controller I've got is the one to go with, if it works.

Now I have to come up with a 50A battery that's safe and easy enough for a non-enthusiast. Any suggestions, other than use two batteries in parallel?

This is a project some of my friends and I are doing as a gift for a seriously injured bandmate, so we want it to work well, but there isn't a big budget for it. I'm donating the bike and the motor kit and putting it all together.

I'm a big fan of EM3EV batteries with individual cell fusing, top quality BMS with extremely low quiescent current drain (i.e. won't go flat if you leave them unattended for a year or so), etc.

You might also consider spending some budget on a CA3 and getting a lower C rate battery if that seems to fit the requirements better. The CA will let you set a lower Max Current for the controller to match the battery (instead of the other way around), get him selectable power levels on the bars (good at least for walking the bike vs riding), autocruise, PAS if he wants it, and the usual Amps/Volts monitoring features. It can also ramp the throttle for softer getaways and give a more controllable throttle using Current Throttle mode. You would need to check if you have the 6 pin CA-DP connector on the controller or else get a CA external shunt from Grin.

None of these features are strictly necessary and you need to weigh the battery costs, etc, but the CA can help make mismatched components work seamlessly together so you can get the parts you like or can afford and then rely on the CA to make them play nice. Just an option....

When I saw the wiring last nite, I knew it was professional and was thinking an early HPC kit too.
I just wonder if this motor/controller combo wouldn't be serious over-kill for a rehabilitation bike.
If they test out, selling those components could finance something like a Cute Mini-motor and a 5-level PAS sine wave controller, a more user friendly system.
Given the BMC is a relatively heavy motor and it's going to want a heavy batt, my thinking is a mini-motor with a lite-weight batt and lite-weight donnor bike would be much easier for your friend to, not only ride, but to push it around as well.
Not sure what the BMC kit would be worth today, but it was a $2000 kit (over-priced by HPC) when it was new.
Anyhow, that's what came to my mind when I saw what exactly what you had.

motomech said:

Given the BMC is a relatively heavy motor and it's going to want a heavy batt, my thinking is a mini-motor with a lite-weight batt and lite-weight donnor bike would be much easier for your friend to, not only ride, but to push it around as well.

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You might be right, but at this point he can't even really walk yet. He needs a feet forward bike that can run adequately without any pedal input at all. But I also want to set him up on a drag-free bike so in time he can ride it without motor power as appropriate. I have a bike that's doable for feet forward riding position, and it's a heavy cruiser. This kit I had sitting around already seemed to check all the boxes, but it will require a big and costly battery.

I think that a Q128 in a low speed range would do the job, and I could probably get both a motor kit and a workable battery for near the price of just a 48V 50A capable battery alone. It would not be my first choice for the bike I have already, though.

teklektik said:

AFAIK, the BMCs always had wonky timing and draw about 5A unloaded.

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Does it become more efficient with a load on it, or does this amount to a 250W penalty whenever the motor is running?

It's not clear to me how fast the BMC motor would be on 48V. Was it only made with one winding? It's laced into a 700c wheel now, but I was thinking of putting it in a 24" wheel with a wide rim and 3" tire (so roughly equivalent to a 26" wheel).

Seems like it might be too much motor for the job. But it has the advantage of being in my possession, with an accompanying controller.

I'm inclined to put money towards more battery rather than a Cycle Analyst, given that this guy is not an enthusiast nor particularly technical. But if the result is a 35mph bike, that's not good.

Chalo said:

Does it become more efficient with a load on it, or does this amount to a 250W penalty whenever the motor is running?

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The loss is clearly rpm-related but the bike can never achieve that unloaded speed on the road. I don't really understand (and haven't thought about) the reasons for the high unloaded current, but I can tell you that I often run with PAS adding only a very very modest 60W or so at meandering bike path speeds. The motor is not a power hog or grossly inefficient if that's what you are asking.

Chalo said:

It's not clear to me how fast the BMC motor would be on 48V. Was it only made with one winding? It's laced into a 700c wheel now, but I was thinking of putting it in a 24" wheel with a wide rim and 3" tire (so roughly equivalent to a 26" wheel).

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That's probably a V2 motor which cam in a 'Speed' and 'Torque' models. Both are in the ebikes.ca simulator. You just need to go and play around with some configurations. At 48V with a 26" wheel those two motors will do about 30mph and 24mph respectively for any controller over about 25A. Any Amps over that amount are not going to give speed but will give acceleration and hill-climbing power.

Chalo said:

Seems like it might be too much motor for the job.

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I think not. This motor is light by DD standards - even compared to the common 9C clones. This motor will have good getaway torque so your friend won't have to work to get going and up to speed.

Chalo said:

I'm inclined to put money towards more battery rather than a Cycle Analyst, given that this guy is not an enthusiast nor particularly technical. But if the result is a 35mph bike, that's not good.

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A quick look at the EM3EV site shows a 48V shark pack + charge for under $400 and a 9 FET programmable controller with bar mounted power selector switch and programming cable for under a hundred. This gets you a wimpier controller that you can program to match the battery. You can play with getting a 36V battery that will give a bit more current than the 48V (More P, less S) but you want to pick a motor unloaded speed that's about 125% of your target max. (And of course there's that annoying shipping from China that's not to be overlooked....)

Anyhow - lots of options. Again, I'd start by powering that thing up and measuring the unloaded speed (assuming you have access to a battery of some sort). You just want to figure the Kv. According to the simulator the 'torque' wind has a Kv of about 7.6 and the 'speed' wind a Kv of about 10.7. With that in hand you know which motor to select in the siulator and parts choices should be pretty clear from there....

But if the result is a 35mph bike, that's not good.

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I guess you subliminally knew how fast it will go, this guy gets 35 to 38 mph w/ a 52 V battery and the 2500 Watt kit (What you have).

https://motorbicycling.com/threads/hi-power-cycles-xc-104-e-bike.35337/

There was a long thread on HPC kits that basicly turns into a shouting match;

https://endless-sphere.com/forums/viewtopic.php?f=3&t=17846

I have a new Q100H 201 (low speed) frt. mount I laced into a Alex DM24 24" rim w/ DT Swiss spokes I have been thinking about selling. Since it would go to a good cause, I could let it go reasonable. 16 to 17 MPH on 36 V and 19 to 20 MPH on 48V. Also have a 20 A KT sine wave controller and LCD-5 display to run it.

motomech said:

I guess you subliminally knew how fast it will go, this guy gets 35 to 38 mph w/ a 52 V battery and the 2500 Watt kit (What you have).

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There's no way on earth that the V2 spd will go that fast. I get about 40mph at 66V with two motors on my bike - almost exactly what the simulator predicts so I know the simulator Kv is correct.

I'm pretty sure he had one of the rare and short-lived V3 speed winds (basically a 6T I believe). The Kv works out right.

teklektik-Chalo and I are talking about swapping motors. I have a new new Q100H (201, Frt.) laced in a Alex rim and a couple of controllers that might suit his needs better.
He has been busy and has tested the BMC, here is his report;

I have findings about this BMC motor and controller. First off, they worked together fine once I crimped a JST on the controller Hall leads and faked up a battery connector for my 48V Shark pack.

This motor is stupid fast. Full unloaded speed on my 13S battery was about 700rpm. !!!

I didn't really believe it at first, so I used a variety of strobe apps and tone generators to verify what I was hearing. I put a zip tie on the spokes that could pluck the workbench as the wheel spun, and I made a video that I can send to you. I was getting very close to 11.80 hz (708 rpm) from the wheel while viewing the label with a couple of different strobe apps.

Anyway, best indications are a hub kV of about 13.

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Could it really be this fast? Could it be that "rare" V3 you refered to?
Thanks for taking the time to read this.
motomech

motomech said:

teklektik-Chalo and I are talking about swapping motors.
...
He has been busy and has tested the BMC, here is his report;

I have findings about this BMC motor and controller.
...
Anyway, best indications are a hub kV of about 13.

Click to expand...

Could it really be this fast? Could it be that "rare" V3 you refered to?

Click to expand...

Yep, that sounds like it. This is a way fast motor. The regular V2 Spd wind was an 8T and the V3 was a 6T.

Here's how you figure out the Kv for a motor in the ebikes.ca database:





So, we see here the Kv for the 8T is about 10.4. The Kv for the V3 is going to be 10.4 * (8T/6T) = 13.8 rpm/V. Throw in some losses for the high rpm with 0.5mm lams and this works out to be pretty much what Chalo measured. So this is most assuredly a V3.

Since that controller has a jumper for 36V (see the comment in the picture above), you could run it that way. The 6T motor isn't in the ebikes.ca database, but we can use the Advanced settings to adjust the 8T V2 Speed motor in the database for the Kv of the 6T. Here's a snap showing that adjustment with a 215lb bike and 24" wheel. This shows a top speed with that controller of about 29mph which would make for a nice cruising speed of 29mph * 80% = 23mph. We could also use Chalo's actual Kv measurement which should give a slightly slower top speed. This result could be lowered as required with a CA or lower current controller. Since all motor winds behave the same while the controller is battery current limiting, this 6T is going to pull the same as 10T or whatever while accelerating/hill climbing and use the same current, etc. You just have to tame the top speed/ high Kv with a lower voltage battery.





This motor might still work okay, but the battery purchase is going to need to be lower S and higher P to get the same desired Wh capacity. Normally you might lose some power due to wimpy phase wires adding a bit of extra I^2R heat losses from the higher phase current of the high Kv motor, but that setup is already gauged for big phase current so no extra attention should be required.

You might still like to switch to a smaller motor, but I'm not sure I see a compelling reason based on what is in hand. This thing may not have been a first choice for this application, but it doesn't look entirely unsuitable and would leave a little room for more GO when the guy heals up.

A sleazy thing to do if you wanted to avoid the CA with its speed / current limiting, etc would be to put a resistor divider on the throttle output to kill the top speed. This isn't the best means to go after the top speed problem, but it's a 25 cent option to slow down this big motor/controller setup. This has essentially the same effect as the Infineon 3-speed switch - it proportionally lowers the max PWM ratio so the controller can't be driven to block commutation (100% PWM). You can see this in the simulator by cranking down the throttle somewhat - with this big controller the getaway torque will stay about the same, but the top end will be nipped.

So - not pushing for this motor/controller, just sketching out some options to minimize cost since this is a low budget project. The hard decisions remain with Chalo

Thanks for the response, very informative. And now Chalo knows exactly what he has.

I've ordered a 24V 500W Unite brushless motor controller to see if that will turn this uselessly fast hub into something appropriate. Half the voltage and a quarter of the wattage should make it do what it was intended to do. If the timing is wrong or there's some other deal breaker, well I only have thirty-something bucks riding on it.

Now to find a decently capable 24V battery pack. Most of them seem to be rated only 15A continuous.