MAC 500W 8T Conversion

[flymeaway]

Pictures of the battery box construction in progress. Made same way as the other two constructions. There are a lot of additional wires in this conversion and I believe the only available space to use is above the top of the battery.
This will need some thought. One thing about a Bafang mid-drive conversion, the wiring is much simpler and less cluttered.

 

[George S.]

That’s a beautiful pack. Most of us would be hard-pressed to do anything like that. I’m sure you want the weight in the center.


These guys are using 12 large LiFePo cells in their pack (only 12ah each) and it’s an interesting design. They offer a spare battery. Not sure if you could just buy a battery, but it wouldn’t fit all that well, anyway, on another bike.


https://www.kickstarter.com/projects/212162365/spark-a-truly-affordable-fully-equipped-electric-b

 

[flymeaway]

The Battery Box is almost complete. On to wiring. Unfortunately the Infineon controller and Grin CA3 come with excessively long wires. I'll be shortening the Infineon wiring harness to make securing the wires to the frame more manageable. This was not an issue with the Bafang mid-drive conversions, wiring was "plug and play" and much cleaner.

 

[George S.]

That is a big battery box. Completely professional. Since you did the Elite with the MD and this with the hub, maybe you can get a sense of the relative efficiencies of the two motors. That seems to be about the limit for battery power, but you want the speed and range. That chemistry is not lightweight, but it's a lot of power for the money.

Right now, honestly, I think I would go with a 350W Bafang kit and a bottle battery, and figure it is plug and play, at least as an integrated kit. It's nice to have the battery and the motor in close proximity. I don't need speeds over 20mph, and the mid-drive gives the climb capability.

Maybe there will be a BBS03 with a shift sensor this year.

If you have a moment, how does the Cafe Latte compare to the Elite? I have the Elite. It's great value for money, a very useful bike.

 

[flymeaway]

If you have a moment, how does the Cafe Latte compare to the Elite? I have the Elite. It's great value for money, a very useful bike.

The Elite is at home and the Cafe is in my office so I haven't seen them side by side. The biggest difference is the rigid front fork on the Cafe vs. the shocks on the Elite. Both bikes are the same frame size so they seem to be very similar geometry. I have a feeling (just looking at them), that the Cafe has a slightly shorter wheelbase???? I rode the Elite all last summer commuting and wasn't particularly gentle with it, the roads in NH are bumpy and I have to travel 2 miles on a rocky gravel class 6 (virtual cow path) and with over 2500 miles on it, the bike is running no problems and the Bafang 500W BBS02 runs like day one....I like the bike very much.

I agree with your conversion idea, the Bafang Mid-Drive and a bottle battery would be an easy retrofit and give you a very capable ebike.

Court J.

 

[flymeaway]

WOW...WOW...WOW. OK, now I know why the MAC 500W is a highly recommended motor. Easily (with emphasis) more torque then the Bafang 36V 500W, and I suspect that at 48V it would probably be as good or better then the 48V, 750W Bafang. The acceleration from a near stop to 26MPH is really unbelievable (scary unbelievable). Haven't taken the speed limit off 26MPH, but when I have the chance I'm gong to take it out on a flat without the upper limit and see how fast it will go, I'm pretty sure I won't want to ride it to it's limit.

I should have the bike finished next week and hopefully the roads and shoulders will be free of snow so I can take it out for a long ride....and get a good idea of it's continuous power output and hill climbing ability.

Court J.

 

[flymeaway]

The MAC 500W, Motobecane conversion is done! I have tweaked the CA3 and put it in Power Limit mode with three distinct settings:

Level #1 limits the motor output to 250W
Level #2 limits the motor output to 350W
Level #3 limits the motor output to 500W

I adjusted the voltage gain feedback loop to provide a steady power increase curve to avoid power spiking. The result is smooth and powerful acceleration like nothing I have achieved on my other bikes. On the 3rd power level I can accelerate on the flat from standstill to 28MPH in about 8 seconds. The torque output from the MAC hub is nothing short of phenomenal. This is by far, a more powerful bike then the Carbon, or the Elite BBS02 36V 500W mid-drive. If I hadn't built the conversion I never would have believed the MAC motor was that much more powerful.....I am extremely pleased !!!!!!

 

[George S.]

Maybe the world is full of $100 rear hub motors, 500w or so, and expectations are low. I went back to the first thread to verify your battery voltage. This motor is interesting enough that I went ahead and bought the front wheel 350w version. Not sure what kinds of watts this thing is drawing to get that performance. Have fun.

https://electricfatbike.wordpress.c...ur-mac-hub-motors-or-suffer-the-consequences/

 

[flymeaway]

Not sure what kinds of watts this thing is drawing to get that performance. Have fun.

Hi George,

Because I'm using the Cycle Analyst I can give you that info. Peak watts I've seen while riding is 540 and the peak amperage used is 18. The Cycle Analyst is a great unit, you can change quite a number of parameters to achieve the drive output profile that works best for you. I have "tweaked" the power curve to provide a fairly low starting power and adjusted the power gain per second so the motor doesn't draw peak power until the bike is moving at a reasonable rate. The motor should run cooler and the battery should last longer because I'm not trying to drive the motor at a high output when the bike is moving at a slow speed. The Cycle Analyst far exceeds the capability of the Neo Carbon control and the Bafang units.

Court J.

 

[George S.]

On the 3rd power level I can accelerate on the flat from standstill to 28MPH in about 8 seconds.

CJ

I have a Prodeco X3 with a DD hub motor rated 500w (750 peak). I found a flat area and decided to run 0-20 tests. It won't really go faster than that, maybe because of a software limit. Anyway, you say your bike goes from 0-28 mph in 8 seconds. My time is around 12 seconds to get to 20. The standard 500w motor never actually feels 'responsive'. To get off the line I can move the throttle all the way or just a quarter turn, and nothing feels very different. Getting to 4 mph is a chore, for the motor, so I tend to pedal immediately. After the initial struggle to get going, the motor is getting in a sweet spot, so it will accelerate pretty well to maybe 16 mph. Then it's struggling to get to 20 mph.

This is not a dig on the Prodeco motor. It's probably a $100 motor, and they make millions in China. The MAC is many times more money. But the basic motor is really only responsive at maybe 10 mph, in that range, where you get some sense the throttle is more than an on/off switch.

Thanks for the wattage numbers. I get the idea that this motor can take a lot of watts and do more than generate more heat. You picked a high RPM, I think? It's interesting it stays around 500 watts on the high side. You should know exactly how long the battery will last, versus speed. People forget that range is something you can control.

The bike has a great 'industrial' look to it. The battery box is a work of art. Not sure if you'll love the frame with that much power, but hopefully it will last a couple of years. Boredom, by then, anyway.

Nice of you to share all this.

George

 

[flymeaway]

On the 3rd power level I can accelerate on the flat from standstill to 28MPH in about 8 seconds.

CJ

Anyway, you say your bike goes from 0-28 mph in 8 seconds. My time is around 12 seconds to get to 20. The standard 500w motor never actually feels 'responsive'.

George

I don't have a throttle on the bike, I start in the mid range of the cassette and the 48T chain ring. Pedaling hard with the switch set to level 3 the bike accelerates quickly to about 12MPH, shift to 11T on the cassette and by the time 6 seconds has elapsed the motor is running at 500W and accelerating extremely quickly. It took a while to set the gain rate to match my pedal cadence so the motor didn't peak at 500 Watts until the bike was nearing the top speed 28 MPH. Once the motor is putting out 500W pedaling it to the top is almost effortless. It doesn't bog down or hunt and overshoot the max setting which shuts the motor off until it drops back within limits. The smooth acceleration allows the motor to rapidly move to 500W without the issue of overshooting. The Cycle Analyst makes all the difference in motor performance. Now that I've used it in a conversion, I don't think I'd do another without it, or an equivalent or better controller.

Court J.

PS....it's a big battery!!! I really wish I had a 3D printer to build custom fit battery boxes....I've considered it.

 

[George S.]

Hi George,

I bought the bike for the frame (which is very good) and the basic solid component set which is also very good. The hub drive was purchased installed in a Alex DH19 rim using Sapim spokes from EM3EV. Basically a very solid wheel. I wanted a more powerful rear hub then my Carbon and all the research I did on hub drives pointed to the MAC. This bike will be my primary commuting bike and I wanted a good high torque bike capable of giving me continuous 24 ish MPH on my 28 mile round trip, up hills and on the flat. For the cost I don't think you can beat the MAC 500W motor for performance. When you put the new wheel on the back of the Cafe' Latte you have a high quality aluminum frame with a great rear wheel combined with good Shimano components and good Tektro disc brakes. Including my time, the bike cost breaks down as follows:

Bike $499
Wheel and motor delivered $429
36V 15 AH battery $300...6 week ocean freight saved a bundle
GRIN technology components $400
Misc. $75

Basically a $1,700 out of pocket cost. From all the research I've done I'm quite certain this will be a faster more powerful bike then the Carbon. It will be interesting to compare it to the other conversion I did using the 500W Bafang mid-drive Motobecane Elite. I'm assuming similar performance.

Court J.

Court,

I've noticed a few sellers on Ebay offering the 15AH versions, which seems to be what you have. I think you mentioned they are the pouch or prismatic LiFePo cells, so a simple set of 12 large cells. It seems pretty appealing, and two of the vendors have good ratings (99%). It took me a while to figure out how simple these packs are, though they are quite large.

I was wondering if you went with one with a BMS. It seems to add $30 to the cost, and they are a little harder to find.

Glad I followed you down the path on the MAC. I've had a couple of opportunities to test it out (bad weather) and I'm not really sure why they rate it 350w, since it seems to pull 1000w, at least up a short steep grade. Very impressive motor.

Not sure why more people don't go down this path. A real ebike company could go with a rear motor. The front was simpler and I upgraded the fork to steel. The overall weight of the bike is just great.

So, just hoping everything is going well with the BD bikes and the LiFePo pack. Thanks. Any reason for you to go with a 48V?

 

[flymeaway]

Court,

Thanks. Any reason for you to go with a 48V?

Hi George,

Below is a link to the Ebay 36V 15AH battery I bought. Since I wasn't in a hurry the long lead time to get the battery wasn't a problem and it was a great price. The MAC 500W Motobecane has 300+ miles ridden, without any problems, and the battery works flawlessly. The Elite Bafang Mid-drive has 2,500 miles and counting without any problems, so I'm quite pleased with the conversions. Ironically, the only bike I've had any problems with is the Neo Carbon, I'm constantly breaking spokes on the rear wheel. This winter I'll be relacing the wheel with Sapim spokes the DT Swiss aren't cutting it. We all know the 9AH batter on the earlier models is woefully under capacity.....and it shows, the other disappointing part of the Neo Carbon.

As far as 48V goes....great on the tandem, but from what I can see not really necessary on a single.

Court J.

http://www.ebay.com

 

[George S.]

The Neo bikes are nice looking, but they lost me with that 9AH battery. Neo was selling it everywhere else in the world with a 12AH, I think, but they took forever to get here. And then I think it was $200 more. I’m sure the LifePo batteries would make it hard to streamline a Neo, but it’s a lot more useable power. Sorry the store bike is proving troublesome. They look nice, but they don’t seem to be all that great as bikes.

Been using LiPo RC batteries with the MAC. Might explain the peak currents, since the pack is rated 30C, That’s a lot with an 8AH pack. The ocean shipping would be OK. I’ll baby the Lipos and maybe carry them as a ‘reserve’ if I can get the Lifepo configured. Only 4 pounds. The best thing about these kits is that the battery system is totally open, so you can be flexible about different batteries and supplemental batteries.


Thanks again.

 

[Deleted member 803]

Hi George,

Below is a link to the Ebay 36V 15AH battery I bought. Since I wasn't in a hurry the long lead time to get the battery wasn't a problem and it was a great price. The MAC 500W Motobecane has 300+ miles ridden, without any problems, and the battery works flawlessly. The Elite Bafang Mid-drive has 2,500 miles and counting without any problems, so I'm quite pleased with the conversions. Ironically, the only bike I've had any problems with is the Neo Carbon, I'm constantly breaking spokes on the rear wheel. This winter I'll be relacing the wheel with Sapim spokes the DT Swiss aren't cutting it. We all know the 9AH batter on the earlier models is woefully under capacity.....and it shows, the other disappointing part of the Neo Carbon.

As far as 48V goes....great on the tandem, but from what I can see not really necessary on a single.

Court J.

http://www.ebay.com

The Neo Carbon early builds had the rear spokes inserted backwards and the spoke holes on the hub were too large. This has been rectified and you should seek warranty replacement at your local dealer. And by rectified I mean Easy Motion should send the dealer a complete new wheel with motor.

 

[flymeaway]

The Neo Carbon early builds had the rear spokes inserted backwards and the spoke holes on the hub were too large. This has been rectified and you should seek warranty replacement at your local dealer. And by rectified I mean Easy Motion should send the dealer a complete new wheel with motor.

Thanks....did you have this problem on your Carbon? Does BH acknowledge the issue, without debate?

Thanks...Court J.

 

[Deleted member 803]

Thanks....did you have this problem on your Carbon? Does BH acknowledge the issue, without debate?

Thanks...Court J.

Yes, I had the problem. Regional rep not only denied the problem but admonished me for buying out of state. Called the purchasing dealer who called the Midwest rep who immediately sent a new wheel to my local dealer. My local dealer called the purchasing dealer and both concurred immediately on the problem.

To be fair a broken spoke once in a while does happen. I had 4 spokes break all at once.

 

[Bike_On]

View attachment 2550 The MAC 500W, Motobecane conversion is done! I have tweaked the CA3 and put it in Power Limit mode with three distinct settings:

Level #1 limits the motor output to 250W
Level #2 limits the motor output to 350W
Level #3 limits the motor output to 500W

I adjusted the voltage gain feedback loop to provide a steady power increase curve to avoid power spiking. The result is smooth and powerful acceleration like nothing I have achieved on my other bikes. On the 3rd power level I can accelerate on the flat from standstill to 28MPH in about 8 seconds. The torque output from the MAC hub is nothing short of phenomenal. This is by far, a more powerful bike then the Carbon, or the Elite BBS02 36V 500W mid-drive. If I hadn't built the conversion I never would have believed the MAC motor was that much more powerful.....I am extremely pleased !!!!!!


View attachment 2553 View attachment 2550 View attachment 2552 View attachment 2553

Nice detail and report there Flymeaway. Several guys on ES forum rave about MAC motors.

Comments: spec and performance wise, you seem to have hit the nail on the head. I suspect you will eventually swap in some front forks. At higher speeds, you will want them, especially in NH back roads.

2nd, as good as you are with the battery box, it looks like a DIY mis-match with the rectangular box in a triangle frame, and wire ties/cables abounding. Part of the DIY life. After market kits like Bionx and Falco and much cleaner looking with internal controllers, but one looses the flexibility of the CA3. (except Falco does have remote motor control)

On the Lifepo4 battery, are you protecting deep discharge with the CA? How well does the BMS balance?

Thanks again for the updates.

Dan