MAC motor questions

Got a few questions on the MAC 500/1000W from em3ev. The reason I am going with it is because its a geared motor, everything is included and is the same price as the H3540 wheel/motor alone. I priced out shipping from em3ev and it seems to be around $80 to $100, so I am at $500 for a geared hub motor delivered that I can bike with no drag. I still need the charger ~$40 and batteries ~$200 for 44.4V 11Ah 20C, plus S&H another $50. So $800 all in.

What kind of discharge rate should I be looking for at HobbyKing American Warehouse, is 20C good, or should I be looking at like higher rates like the 25C, 30C or even higher? Also what kind of Ah is decent, like perhaps a 10Ah or 15Ah or mroe? This is my first ebike, so I think if I get my toes wet I will get hooked. I've biked all my life, getting older, getting lazier, dont like the hills too much anymore, never really did like the hills, love to just cruise and let the wind blow through my hair. Like to go crazy every now and then.

Do the geared hubs have more torque then a comprable DD?
Can the DD can be "juiced" more reliably then the the geared ones?

What would be a good motor speed for a 26" mountain bike thats got wide knobby's, with a 300lb rider. I was thinking I would turn the motor on and pedal for the flat sections, or slight up hill climbs, then there is the occassional steep hill.
200rpm loaded @ 36V 12T 15mph - 25kmh and at 48V 21mph - 34kmh
255rpm loaded @ 36V 10T 20mph - 32kmh and at 48V 25mph - 40kmh
320rpm loaded @ 36V 8T 24mph - 39kmh and at 48V 31mph - 48kmh <----------This is the one I was eyeballing, the 8T at 48V.
410rpm loaded @ 36V 6T 29mph - 46kmh and at 48V 36mph - 58kmh

If I understand this correctly I got either speed or torque or a combo of both, so 6T is speed, 12T is torque.
I think I will initially buy 48V batteries from Hobby King. What are the general thoughts on pumping this motor up to 48V?


Are the Infineon controllers any good? The 4110 are the ones to get right, or the 3077 does it really matter?
Here is my selection for the controller
6 fet 25A (36V-52V, IRFB3077)
9 fet 30A (36-52V, IRFB3077)
9 fet 30A (36-75V, IRFB4110)
12 fet 40A (36-52V, IRFB3077)

calab said:

What kind of discharge rate should I be looking for at HobbyKing American Warehouse, is 20C good, or should I be looking at like higher rates like the 25C, 30C or even higher?

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20C @ 5Ah is 100 amps - more than you're likely to ever put out. However, depending on the brand, some of these C ratings may be a bit optimistic, and if you were approaching about half of the claimed C rate, then you might want to either increase the capacity of your pack, or get a higher C rating.

calab said:

Also what kind of Ah is decent, like perhaps a 10Ah or 15Ah or mroe?

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How big is a decent fuel tank? Depends on whether you're talking about a city car, a 4WD camper, or a race car, right? Too many variables, but I found 10Ah gave me about 40km averaging 30km/h, occasional top speeds of 45km/h, with light pedaling and moderate hills. Your mileage may vary.

calab said:

Do the geared hubs have more torque then a comprable DD?

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If by "comparable" you mean same size and weight, sure. A geared hub has a hell of a lot more torque than the same size and weight direct drive. Most of them have a reduction ratio of between 5 and 12. But you'd be hard pushed to find a direct drive the same size as a compact geared hub. Apples and oranges comparison. Both are fruit, but there the similarity ends.

Can the DD can be "juiced" more reliably then the the geared ones?

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Yes. Direct Drives generally will tolerate over-volting and over-amping than geared hubs. No nylon teeth to break, bigger thermal mass to disperse heat.

calab said:

What would be a good motor speed for a 26" mountain bike thats got wide knobby's, with a 300lb rider.

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Another how long is a piece of string, but at least you've provided some info.

No offense, but let's just say you're no Jack Sprat, and wide knobblies have been tested to chew up as much as 110w of power at 40km/h. The starting power to overcome both inertia and resistance is going to be significant. You'll get similar problems up hills.

Unless you're looking at pushing the MAC 8T to its maximum (about 1500W reliably, or 1800w, if you're happy to oil fill it), I don't think you'll get to the advised speed of 48km/h. If you never intended to go that fast, perhaps you'd be better served with a 10T, which would help you off the line, up hills, and generate less heat than an 8T.

calab said:

I think I will initially buy 48V batteries from Hobby King. What are the general thoughts on pumping this motor up to 48V?

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I'll tell you when I finish building mine... 8T on 12S Hobby King Lipo. I have a 1000W controller, and a 800W continuous (1600w burst) controller. I weigh about 155lbs, hills ranging from -19% to +19%.

calab said:

Are the Infineon controllers any good? The 4110 are the ones to get right, or the 3077 does it really matter?

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Sorry, no experience here.

calab wrote:
Are the Infineon controllers any good? The 4110 are the ones to get right, or the 3077 does it really matter?


Sorry, no experience here

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Yes they are a good choice.
Many here are running Infinions.
Lyen sels them, also Keywin (ecrazy-man) and Cell_man. many Crystalite are Infinions.
4110 fets are for higher voltage and current. 3077 are used in lower voltages below72v. they run cooler.

As for the wind pick, for what you want and need is a 10t and 48v for a easy setup. EM3ev has it all. His kits and batteries are plug and play, no need to change plugs to match.

I have 4 Macs 3 8t and 1 7t. haven't used the 7t yet but sure love the 8t. 30+ mph on 44.4v LiPo with 26 x 2.35 tires and total weight of 235 lbs.

Dan

Sunder said:

Yes. Direct Drives generally will tolerate over-volting and over-amping than geared hubs. No nylon teeth to break, bigger thermal mass to disperse heat.

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In my experience, the gears used in the MAC or BMC motors are fine, it is the clutches and keyways that will fail if you run more than about 2000w+ peak.

Go with Em3ev's controller (Cell_man) for the MAC as his will be smoother than the others as it is specially programmed for that motor.

I have the 8 turn and tried out the 10 turn. I never use the top speed at all. It's too fast for my liking and will get you unwanted attention. The 8 turn is quite good at going up hills but the ten turn just loves them. 40kph is still very fast for a bike.