24 Volt Middrive- Don't Bother!!!

I just finished my proto-run on a completed DIY middrive using a 24 volt 20 AH LiMn02 battery and a 600 watt Mac motor. It all sounded great on paper and even in theory, but the real world results sucked. Bottom like- 24 volts isn't enough "UMPH" to get the motor to a high enough rpm to do the hills. I even had a 38 tooth front chainring (derailleur), and a Shimano ultra-low gear on the freewheel. It actually bogged down on steep hills! AND the noise was horrendous- chain noise doesn't make for pleasure rides, at least not the grindy kind......Yeah, it's time for a BBSHD!

what kind of motor controller ?

That is the Little Mac, It will run on higher voltages,
before spending money on a very heavy Mid-Drive,
Just get some cheep batteries for experimenting with higher voltages and amperage.

For that Hobby King Lipo's are great you could buy just two . ( 2 6s packs )
or ( 2 7s packs ) to start with .

( If you have some RC Buddies you might even to able just borrow some for testing, just need to make your own wire harness which is very easy.
If you lived near me I would help you with the testing.

Then when you dial in the correct Voltage and Amps that works for where you want to ride and hills you want to go up , just buy 2 more to make a larger Ah. Pack.

Really do that before anything else.

That little Mac,

Will run at 21 Amps Continuous . ( I would probably keep it at 20 amps when using 16 s)
And
I just went back and looked , it will run at 14s ( what people also call 52 volts )
and
At 16s !

There you go ....get some 7s packs or 8s packs.

I have some 7s packs and 8s packs if you are anywhere near to me and can get over here. In my area there is every grade / percent of hill and length on hill , you could want for some of the best testing in the U.S. . ( there is plenty of Camping around where I live so not much cost there )

Cheap Cookie, this is a MAC 24 volt "INTERNAL CONTROLLER" motor. Currie put many of these on their Currie "e-rides", and later they were put on Synergy, Lashouts, and Rayos ebikes. All had internal controllers, and tended to have low rpms delivered to either their 370 watt (2" cooling fines), or their upgraded 600 watt BMC motor (3" cooling fins). I don't know their amperage limit. The 370 watt was dependable, but the 600 watt usually burnt out its internal controller, and couldn't be replaced. My MAC motor is an upgraded version of the 600 watt BMC, with reengineered internal controllers which are alot more dependable, but cost $400......At any rate, the rpm delivered to any of these finned motors is less than optimal for high torque...........ScooterMan, these motors won't take 36 or 48 volts, because of their 24 volt internal controller. Bypassing the controller is a huge hassle according to many who have tried......Now, there is a variable voltage BMC that will take 36 or 48 volts maybe this is the one you're talking about. It is the 2" wide, unlike the 3" wide MAC on my middrive, and am wondering if it will handle 48 volts up a steep hill. This is my next project, but since the noise of the motor-to-sprocket is so grindy, I'm abandoning middrive route and will attach it back to its stock connection to the rear wheel, like a hub motor. I'm hoping that this motor (see picture)when run off 48 volts will do the hills better than the 24 volt middrive, because of the higher voltage/rpm......I'm waiting for the 48 volt 25 amp controller to arrive from BMC and will let you know how it goes......I have driven the Pedego 500 watt 48 volt ebikes nongeared motors and, to my surprise, do the steep hills quite well. and have a more accommodating cadence for peddling. I'm still a believer in middrives for hills, but I'm exhausting all my options before I blow 2 grand on a BBSHD and a Jumbo Shark 48 volt LiMn02. By the way, Scooterman, I live around the San francisco Bay area, about an hour south of San Jose, in a small town called Aromas. If you live nearby, great! Joe

Joe,

You live only about 35-45 minutes from me, by car.

So when you get the controller ( 48 v ) that you write about and hook it up to your motor let me know,
If you want to come here and hook up a few battery packs for testing.
I have a 48 volt 11.5 amp hour battery pack ( 18650 cells ) that is rated at 2c , so the most I pull from it
is 20-21 amps.
And
I have some 7s lipo's that are rated at 25c , so plenty of reserve amps to be used from those. ( I have 4 of them that I make into a 14s 2 p Pack , 10 amp pack )

With either of those you will have to make your own harness to hook them up to your bike/controller.

I use 5.5 mm bullets on the battery side of the Harness for the Lipo's with hook up to the controller via XT90 Female ( So 5.5 mm Gold Bullets at the battery side of the harness and Female on the other side of the harness ) , and XT90 Male on the wires from the controller . To hook up 14s packs.

( By using Anti-Spark XT-90 Connectors, I get no spark when connecting the battery pack/harness to the controller )
and
On the 13s ( 48 volt 18650 cell pack ) I use Anderson 45 amp power pole ( black and red ) connectors.

Let me know what you use on the new controller you get, XT-90 Anti-Spark Connectors are a good thing to go with at the Battery to Controller Connection.

They can be Bought at Hobby King , or another RC Parts Vendor.

When Making a parallel, or single harness for that mater, for my Lipo's to Controller , I use 12 awg wire.
You could probably use 14 awg if your motor is to be operating under 25 amps .

The motor is indeed a different Mac than I had thought ,
The little Mac I was thinking of is the Mac Escooter Motor , the M12500-3A Escooter Motor

Here ... M12500-3A ESCOOTER MOTOR

The Mac M12500 Series is an efficient, compact out-runner type motor with class leading torque and power. The rated output power can be from 200w to 1000w and rated speed typically between 2000rpm and 4000rpm.

Applications:
Include various industrial applications such as: pump, fan and HVAC amongst others. This motor has also been used in E-Bikes and battery powered lawn mowers. Typically this motor uses shaft output, but has also been configured as a miniature direct drive hub motor.

Specification:
Highly efficient (>80%, typically >85% max efficiency in most cases).
High Power Density (up to ~1000W at 2.5kg).
Rated speed configurable for 2000-4000rpm at supply voltage of 24-48V.
Custom output shaft available. Custom motor structure available with sufficient quantity.
Low noise.

Model M12500-3A
Rated Power(W) 600/750/1000
Rated Voltage(V) 24/36/48
Speed Range(rpm) 2000-4000
Efficiency(%) >80
Noise(dB) <65
Weight(kg) 2.5
Usage e-bike,e-scooter,
textile machinery and
medical equipment etc.

>

Scooterman

Scooterman, it's a small world! OK, I'll check out that MAC1250 motor as another option for my little project. Hopefully it has a "D" shaft, and has a clockwise rotation (most scooter motors are counterclockwise)...or do I have it backwards?....Anyway, this controller is color-coded and shouldn't be too hard to connect it up. I'll take you up on your offer to test this motor on your 48v 2C battery, and test it on a hill where you live. But I may just buy the Jumbo Shark battery pack from Luna because, even if this 48v BMC doesn't cut it on the hills, I'll have no choice but to go for the BBSHD. If you saw the hills around here, you'd agree. Sounds like you live in Santa Cruz- Do you know Daniel at Pacific Ave Cycles? How about Mike at the new ebike shop, Current E-Bikes? I brought a girlfriend there- she wanted one, because I had one- she test drove a Pedego Interceptor, and pulled out her visa card! On the way home she asked why I didn't discourage her from buying it. I said, "I did"

I think I saw this same motor on Ebay auction not long ago. I was thinking of grabbing it but the 24v also stop me from buying. Unless its 24vx50A controller, the torque must be horrendous. Better off get a motor from an electric scooter for a cheapy mid drive conversion.