Raged Focus Black Forest 29er MAC 10T 40A Build log!

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Raged Focus Black Forest 29er MAC 10T 40A Build log!

Post by Raged » Apr 06 2014 2:27am

Hey Everyone,

Just after people's opinions on the motor for a commuter. The path is 14km each way (say 30km round trip) with *mostly* rolling hills/flat however there is 1 hill which is a steady incline for 1.5km. ( not sure on elevation, but its this stretch : https://www.google.com.au/maps/dir/-37. ... m0!1m0!3e0 )

I've pretty much decided to purchase the whole kit from http://em3ev.com however there's so much talk here about durability/heat/chewing gears etc that I'm not sure who to believe. Some other threads suggest putting trans oil in a geared the hub to stop it chewing gears/ticking (I don't have the tools or skill for this).

I'll start with riding conditions... Melbourne has the most f*cked up weather patterns. During Summer we get heatwaves that last for 2 weeks where every day is over 40degC. During winter we sometimes get 2 day heat waves (35degC) between thunderstorms... Its generally good weather for the other 10 months of the year. Reading the other threads here says that I should 100% stick to DD motors to deal with those conditions as the heat would wear out a geared hub?

I was actually after a MAC 8T to run 50km/h @ 48v on a 29er/700c wheel. (Haven't decided on the frame). purely because its less visible and lighter than a DD hub.

shopping list for my original plan of a MAC 8T (paying extra for plug and play is alright)
http://em3ev.com/store/index.php?route= ... uct_id=138

UPGRADE EM3EV VERS. MAC , 500/1000W PICK'N'MIX KIT

Controller : 9FET 30A (36-72V IRFB4110) <-- I see a 12FET version. Is it worth asking for the upgrade?
Motor : 320RPM loaded 8T Motor
Wheel : Rear
Wheel Type : 700C Alex DH19
Throttle : full twist

Battery : 50V 14S 14Ah samsung pack
http://em3ev.com/store/index.php?route= ... uct_id=132

Can you tell me I'm heading in the right direction with the MAC 8T? Should I change to DD to deal with the weather conditions to cope with the few weeks in the year? or something like a 10T to climb the incline?

Thanks in advance.
Last edited by Raged on Jun 11 2014 11:03am, edited 2 times in total.
Focus Black Forest 29er - MAC10T 14S Lipo - 50km/h, 50km range. (dead)http://endless-sphere.com/forums/viewto ... 91&start=0
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Re: MAC 8T or Direct Drive?

Post by neptronix » Apr 06 2014 3:07am

Chewing up gears is a pretty old problem that doesn't occur so much; not with the newer nylon gears anyway. I ran the old white gears for 2 years and never managed to blow the new gray gears after lots of abuse.

I wouldn't call it any less or more reliable than your average DD hub. It's light and a little more powerful than the 9C at 4lbs less. 50kmh on the flats all day long with the upgraded stator isn't asking much of it - that's reasonable, and within it's continuous power level.

Heat comes into play when you beat on it like i did... but despite some spurts of 4000W and some periods of 2600w usage, mine was good.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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Re: MAC 8T or Direct Drive?

Post by neptronix » Apr 06 2014 3:16am

Heat would do a number on any motor, if you were pushing it far past it's rated level and expected it to still cool from the difference in motor temp and ambient temp :)
But since you're not doing that, then it's no problem.

One thing i noticed about the cheap DDs such as 9C and it's clones, is that they loved sicking in water. Seeing the stator start to gain rust pits after 2 rides in the rain was disheartening to me. I figured it would be bad for the MAC, but it wasn't, because if water does make it's way in, it doesn't have immediate contact with the stator. After >3 years of ownership of my MAC and running it as my main motor, the only rust that accumulated on it was on the axle - just as any motor.

But with extended riding in rain, you might have to change the gear oil out maybe once a year?, because if the motor takes in water, it will gradually dilute the gear oil over time. But that beats seeing your motor stator rust away, eh?
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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Re: MAC 8T or Direct Drive?

Post by Raged » Apr 06 2014 3:25am

Thanks neptronix,

I actually read your build log while deciding to build a commuter. You mentioned that V brakes were woefully inadequate (which sorta effects my bike choice). Are you a 100% convert for disc brakes? I've got v brakes on my current roadie (carbon frame with full ultegra) and can stop as good as my tires allow me even travelling 45-50km/h. That said, the road bike is probably 10-11 kg all up... I am however over 93 kg =(
Focus Black Forest 29er - MAC10T 14S Lipo - 50km/h, 50km range. (dead)http://endless-sphere.com/forums/viewto ... 91&start=0
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Re: MAC 8T or Direct Drive?

Post by dogman dan » Apr 06 2014 6:57am

Doesn't sound like that tough a commute for a gearmotor. I became sold on the dd because my commute in 40c was 25k home, nearly every inch of it uphill. About 1000 ft vertical gain. But I was still able to do it on a tiny gearmotor in a test lasting 500 miles. Then I went and melted it on a real hill of 3000ft of vertical, but only the halls failed. That day was the hottest day of the year.

Now, if you said you wanted to run 2000w through that gearmotor for the whole ride, that would be time to choose a dd. Even the really easy to melt brushed hubmotors would not overtemp in less than 10 miles when I was doing my early testing. So I see no particular reason why you must choose a dd for your particular commute of about that length. 50 kph cruising should be taking something in the 1000w ballpark, so I see why Nep says it will work fine. It should at 1000w.

If your route has a lot of stop signs, like one every block, then you will want to choose a cooler running 10T. A fast wind on a big wheel will make more heat getting going. If the stops are one or more per kilometer, it could get the motor a lot hotter than a 10t would get. You'd be getting lots of spikes in wattage getting to 50kph, so it would not be as cool as cruising 50 kph with no stops. If you have shitloads of stops, then getting to 40k faster might be a quicker average speed than slugging up to 50k on a fast wind.

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Re: MAC 8T or Direct Drive?

Post by DAND214 » Apr 06 2014 9:12am

Looks like Dogman beat me to it.

I would go with the 10t if you are running 29 or 700 wheels.
The 8t is great on 26 but not so great with the larger wheel and hills.

10t on 50v will really do great.

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Re: MAC 8T or Direct Drive?

Post by Spicerack » Apr 06 2014 9:32am

Keep the bike weight down and have only enough batteries to do your commute and not much else. My Mac melted very quickly at 15s so a bit more volts but my bike weighs heaps (15kg of batteries alone! ).

In a lightweight setup the Macs are good but if you and your bike are a bit more portly I'd go for the dd. They can also be air vented and cope well with increased power which appeals to those of us who like to tweak. Which happens to be a great majority of us! Yes the Mac can be oil cooled but it's a bit of a pita with leaks which end up on the rear disc.
Norco Shore2
Was Cellman MAC rear oil cooled then 8x8 9C vented and temp probed now 9x7 9C vented and temp probed!
12 FET controller
62V 18650 home made battery pack
50 km/h
http://endless-sphere.com/forums/viewto ... =6&t=32769
MAC Repair thread http://endless-sphere.com/forums/viewto ... =2&t=34806
Oil cooling the MAC hubbie http://endless-sphere.com/forums/viewto ... =2&t=37972

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Re: MAC 8T or Direct Drive?

Post by Raged » Apr 06 2014 10:02am

Thanks for the advice so far guys.

Time for more questions =)

The disc brake option :
As this is a new build, would a cheapish 29er like the Avanti Montari 29.1 be suitable? They're under $500 here from the LBS brand new and comes with a basic disc brake kit and forged dropouts. Would you still recommend a torque arm (looks like it woulnt be too hard to fab a set up for it).

http://www.avantibikes.com/au/bikes/off ... s#tab_menu

The V brake option :
Alternatively I can get a alloy road bike frame with Shimano 105 group set for about $800 ( can be cheaper for the entry level gear set ) http://www.cyclingdeal.com.au/buy/hasa- ... ike/RX1-13 which Im more familiar with. I know I can pedal this setup way faster than the MAC 10T @ 48V (e.g. over 50km/h).

Or just slap it on a $200 cro moly fixie as a commuter?
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Re: MAC 8T or Direct Drive?

Post by dogman dan » Apr 06 2014 10:04am

Is your bike a cargo bike spicerack? Or is it just set up for long rides. I would recommend a dd for rides drawing 1000w long enough to discharge 15 kg of 15s. That's 60k or so?

I do rides like that with a big dd, the good ol 5304. But I kind of doubt 15k will melt the motor, assuming it cools completely before the return ride.

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Re: MAC 8T or Direct Drive?

Post by dogman dan » Apr 06 2014 10:07am

I don't see why that wouldn't work, but if buying new, I'd definitely be shopping in 26" rather than 29er. 26" is already too big a wheel for hubmotors to perform best. But the 10t would make up for some of that.

FWIW, light doesn't mean shit anymore once you motor up. As long as the bike is under 80 pounds with motor and battery, it will feel like it's 10 pounds on the pedals. It will corner like 80 pounds, but put the battery in the frame and that will feel fine.

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Re: MAC 8T or Direct Drive?

Post by Raged » Apr 06 2014 10:11am

dogman wrote:I don't see why that wouldn't work, but if buying new, I'd definitely be shopping in 26" rather than 29er. 26" is already too big a wheel for hubmotors to perform best. But the 10t would make up for some of that.
Which option are you agreeing to??

I'm on a mission to get this done as fast as I can before I go on holidays next month. I got the bill for another year of parking at work... $3900 (including tax) plus another $1300 for congestion/carbon offset. Decided it was time to go EV =)
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Re: MAC 8T or Direct Drive?

Post by teklektik » Apr 06 2014 10:42am

Raged wrote: I was actually after a MAC 8T to run 50km/h @ 48v on a 29er/700c wheel. (Haven't decided on the frame). purely because its less visible and lighter than a DD hub.
...
shopping list for my original plan of a MAC 8T (paying extra for plug and play is alright)
...
Controller : 9FET 30A (36-72V IRFB4110) <-- I see a 12FET version. Is it worth asking for the upgrade?
Motor : 320RPM loaded 8T Motor
Wheel Type : 700C Alex DH19
Battery : 50V 14S 14Ah samsung pack

Can you tell me I'm heading in the right direction with the MAC 8T? ... or something like a 10T to climb the incline?
Raged wrote:That said, the road bike is probably 10-11 kg all up... I am however over 93 kg =(
So we are talking about a 12kg bike + 5kg battery + 4.5kg hub + 2kg misc = 23.5kg bike
23.5kg bike + 93kg rider ~= 120kg with clothes, lock, etc = 264lbs
And you want to use a 700c wheel.

As others have mentioned: It gets down to the % incline and the number of stop/start episodes on the incline. Launching 260lbs in a 29er on a hill is going to need some power - even with your pedal assist. This is entirely different than a straight run. The 8T is a higher speed wind and draws a lot of amps to make torque when bogged down off the line - a lot of which will go to waste heat. You didn't mention which Samsung cell you were choosing, but the ICR18650-22P is only 3C rated.

This gives two big unknowns in the equation: incline and number of stops.
These things working against a more difficult incline: big wheel, heavy vehicle, fast wind, and 3C battery.

Even on a 3% incline the 8T will be pulling 35A - this is less than your 3C (14Ah x 3C = 42A) limit, but more than the 9FET rating - you will need to reprogram it to run it hot for the short 1.5km incline - or spring for the 12FET and probably program it downward a bit to avoid abusing the battery. On a 5% incline the 8T will want to draw 40.5A. In these cases, you will want to either back off on the throttle from 100% or otherwise limit the current to take care of the battery (reprogram controller, get a Cycle Analyst).

Here are some results from a MAC estimator (still in test so take with a grain of salt - useful at least as an indicator for comparison :D) where the controller was set to a 50A limit so we can see what the motor wants to draw - this gives some idea of controller sizing vs motor wind. This assumes you are pedaling 100W. The top esitmate compares a 8T vs 10T on the flat and the midle is on a 5% incline. The bottom estimate is the same hill estimate with 26" wheel. Some of the interesting results are highlighted.
MAC-8Tvs10T.png
MAC-8Tvs10T.png (55.1 KiB) Viewed 6297 times
In the 5% incline example the 8T is dumping about 410W of waste power as heat, so the motor 'should' run the 1.5km without overheating - though it's going to be getting hot - with lots of start/stops (wasteful high current getaways), it will most likely be overheating. On the other hand, a 10T will climb a 5% incline all day and draw only 28.5A. The energy rates should allow you to guesstimate your range at WOT - which may not be the actual way you will be running in any case.

So - for the 8T it looks like a 5% incline is going to be a bit hard on your battery unless you limit/size the controller or go to the 10C upgrade (INR18650-20R). Without any additional details about the terrain and traffic, I would lean towards the 10T and 9FET as a better choice (maybe program up to more Amps to allow brief getaway current spikes). Different wheel size and voltages open up other options and might give you some power/speed headroom for headwind and running in traffic, but there's always lots of 'what ifs'.... :D This doesn't say anything about your DD options, but maybe helps with the MAC side of things.....

Also - you misunderstood the oil-filling - this is for cooling, not to save the gears. As you can see, you can avoid a severe overheating issue by more careful motor/controller selection. It you want to improve your reliability re: clutch (the present weak spot - not the gears) and overheating, get a CA V3 to give you throttle ramping to lighten the stress on getaway and to roll back the throttle in case of overheating. This is much easier than going the oil route, but at only 50v, this is only one (more expensive) option for an 8T and definitely not necessary for the 10T.
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Re: MAC 8T or Direct Drive?

Post by dogman dan » Apr 06 2014 11:23am

Duh, I was commenting on the disk brake 29 er.

But again, the ideal commuter is typically a 26". Rolling resistance and weight means little when you have a motor, but there are much nicer, and more affordable options for what you will be buying over and over, tires.

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Re: MAC 8T or Direct Drive?

Post by Raged » Apr 06 2014 11:28am

Thanks for those calculations! Your numbers and reasoning makes sense. I didn't take into account the link between pulling amps at incline.

When you say 9 FET, are you referring to : 9FET 30A (36-72V IRFB4110) or 9FET 30A (36-52V IRFB3077)?

As both fit into the current draw of your calculations?

Additionally, looking at the em3v site, is the SDI-ICR18650-20R (9.75Ah) - US$470 enough juice? I thought the value that dictates how far you go is the the biggest Ah? Is it fine to get 1 of those packs and see how I go, then get a 2nd pack later if it isn't enough juice?

The minister of war and finance has approved me spending $1500, so I can get one now and sneak another purchase in a few months later =P

or 4 of these https://www.hobbyking.com/hobbyking/sto ... duct=39255 for AU$76.60 each? 2 in series and then in parallel for 52V 11600Ah from the Australian Hobby King store?

Spec.
Capacity: 5800mAh
Voltage: 7S1P / 7 Cell / 25.9V
Discharge: 25C Constant / 35C Burst
Weight: 913g (including wire, plug & case)
Dimensions: 160x46x57mm
Balance Plug: JST-XH
Discharge Plug: 5.5mm Bullet
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Re: MAC 8T or Direct Drive?

Post by teklektik » Apr 06 2014 1:08pm

Raged wrote: When you say 9 FET, are you referring to : 9FET 30A (36-72V IRFB4110) or 9FET 30A (36-52V IRFB3077)?
Actually - the estimates don't account for the FET Rdon - I just cranked the Amp limit up to 50A so you could see what the motor wanted to draw. For your relatively low voltage 50v rig, you will see less loss using 3077 FETs.
Additionally, looking at the em3v site, is the SDI-ICR18650-20R (9.75Ah) - US$470 enough juice? I thought the value that dictates how far you go is the the biggest Ah? Is it fine to get 1 of those packs and see how I go, then get a 2nd pack later if it isn't enough juice?

The minister of war and finance has approved me spending $1500, so I can get one now and sneak another purchase in a few months later =P
You have two issues - range and max current draw. Range is roughly related to the Wh capacity of your battery (V x Ah) and your average enegy use in Wh/mi. The latter is obviously affected by terrain, wind, and driving style. The max current draw is constrained by the Ah capacity of the battery and 'C' (Capacity) rating which is the 1A/hr capacity rate - so comparing two batteries of 10Ah and 1C vs 10Ah and 10C, the first can supply 10A and the second can supply 100A. Flogging a battery at it's max rate will shorten it's life. Since we don't know much about your hill, but knowing the bike has big wheels, is heavy, and the incline is 1.5km, all that can be said is to try for a battery with sufficient Ah to get your range and as much C rate as you can afford. The lower current requirements of the 10T make it attractive as a means to soften the battery requirement.

For instance - looking at the 5% incline above, we see that 10T consumption is about 35Wh/km so to get up that hill will chew up 1.5km x 35wh/km = 52Wh. It won't cost you anything to go down it, so the remainder of your round trip will be 2 x (15 - 1.5) = 27km. A 50v 9.75Ah battery at 90% DoD has about 442Wh capacity. Subtracting out the hill we get 442Wh - 52Wh = 390Wh. This means you cannot use more than 390Wh/27km = 14 Wh/km (23wh/mi) for the flattish part of the trip. This is achievable at lower speeds but you don't have much headroom for wind and battery age unless you are making a noteworthy pedaling contribution (here's the part where folks chime in and say they only use 7Wh/mi - but that level of effort may not be what you want to do going to work). 9.75Ah would be a little shy for me personally.

Here's a tabular example of range - it uses miles, but you can substitute 'km' for 'mi' - the values will still be valid without additional math - this doesn't account for your special hill situation, but it should give some idea. Obviously things get different with headwinds or if you pedal on the flat part (reduces needed Wh/mi), but some extra capacity is Good.
14s9.75Ah-battery.png
14s9.75Ah-battery.png (97.21 KiB) Viewed 6332 times
The only issue with getting another 9.75 pack later is that you will have a whooping 19Ah pack which will be pretty heavy. If you don't mind - go for it - but a more modest 12-14Ah pack might give you a better solution for less money... (Gee - this is never easy is it?)

I strongly recommend that you email Paul at EM3EV and see what he recommends. As a last resort, for a few extra bucks and a little extra time, he can build you a custom battery (added 'p' to increase the Ah) if the off-the shelf solutions don't pan out. Summarize all the facts and/or point him at this thread and see what he puts on the table for you. In the end - this is his business and he's good at it.... :D

If you can track down a topo map or one of the bike-ride-plotter sites to better define your hill situation, some of the biggest questions will go out of this and clarify your needed C rate, etc.
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Re: MAC 8T or Direct Drive?

Post by 999zip999 » Apr 06 2014 4:27pm

Do not get the hobby batteries from Hobby king No. Get a em3ev plug and play battery as no for the big lipo headache. Multi cells packs a power supply then a charger then braking it down to charge. Making a bunch of wires to hook them up and a lvc alarm, just getting started with things needed for lipo. A barbaque to charge and store in.
I do like my d.d. but em3ev dosn't sell a slow wind any more and may stop selling the Muxus d.d. The mac 10t in a 26in rim paul rims and spokes are good and the controller just plugs in, also so does he's battery. Easy peeze.
I have heard people telling you to buy a d.d. motor in a slow speed but they can't find one themself's ? Where is this slow speed 9c or clone d.d. motor ?
Go with the mac you should be happy.

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Re: MAC 8T or Direct Drive?

Post by dogman dan » Apr 06 2014 4:51pm

I tend to agree, you don't have pressing reasons to need the discharge rate of lico, so why fuss with it?

The 9 ah pack from cellman will get you the distance one way I think, unless you have a monster of a hill. 22k uphill all the way used to take me about 13 ah of 48v. .75 ah per mile is my rule of thumb, which includes some reserve. That's for about 35kph traveling. so your 15 k should go with 7.5 ah of 48v. If you are planning on 36v, then 10 ah.

One way on the smaller battery should work.

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Re: MAC 8T or Direct Drive?

Post by kiwipete » Apr 06 2014 5:23pm

FWIW, About the hill. Its a pretty mild hill: elevation (as per pic) is about 2.3% going from left to right and its over about 850 mtrs and then its down hill anyway.
Elevation.JPG
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Re: MAC 8T or Direct Drive?

Post by neptronix » Apr 06 2014 7:55pm

You know, i used to weigh 270lbs, and now i weigh more like 214. I needed the biggest disc brakes i could find back then for a reason. :)
I run kool stop salmond pads ( extra wide ) now and find them to be adequate for fast braking, only because there is less momentum to deal with.

FYI, i hope you aren't thinking about putting such a powerful motor on that roadbike frame. It won't take it.
Raged wrote:Thanks neptronix,

I actually read your build log while deciding to build a commuter. You mentioned that V brakes were woefully inadequate (which sorta effects my bike choice). Are you a 100% convert for disc brakes? I've got v brakes on my current roadie (carbon frame with full ultegra) and can stop as good as my tires allow me even travelling 45-50km/h. That said, the road bike is probably 10-11 kg all up... I am however over 93 kg =(
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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Re: MAC 8T or Direct Drive?

Post by tomjasz » Apr 07 2014 1:10pm

How would cell_mans 8T perform as a front drive? He suggests a DD but I tried weighting my front wheel with weights matching the units and there is a significant difference in handling and feel.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: MAC 8T or Direct Drive?

Post by neptronix » Apr 07 2014 1:50pm

powerful front motors are trouble. Wouldn't recommend it. It's sort of like a truck - the back wheels are apt to slip without a load in the truck bed, because all the motor weight is on the front. Same thing with a bike - the majority of your weight is sitting on the back, so the back wheel has the most traction and control.

A MAC can be very powerful, and thus you need strong front torque plates to prevent the wheel from cracking the fork dropouts if you have a suspension fork. It can be rather difficult to get a good 100% stiff torque plate/arm setup going that can handle a lot of power on a suspension fork.. either that, or you limit yourself to a rigid fork, which you will find increasingly problematic for handling, the faster you go.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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teklektik   10 GW

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Location: CT, USA

Re: MAC 8T or Direct Drive?

Post by teklektik » Apr 07 2014 1:58pm

kiwipete wrote:FWIW, About the hill. Its a pretty mild hill: elevation (as per pic) is about 2.3% going from left to right and its over about 850 mtrs and then its down hill anyway.
Elevation.JPG
Elevation.JPG (11.07 KiB) Viewed 6182 times
Thanks KP! That's actually a nifty plot - where did that come from?

This pretty much takes any imperative for a gear motor off the table. That's not to say it wouldn't still be a fine choice, but with no significant hill-climbing as part of the equation...

So - Raged - what are your thoughts about charging at work? You seem to be emphasizing 'light' but mandating a mid-trip charge is kind of a big choice. Also - what are you looking at for normal travel speed - are you trying to run 50kph for the journey, just want that for sprints, or is it just a handy number to throw out there?
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Build Thread: 2WD Yuba Mundo V4

kiwipete   100 mW

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Joined: Nov 13 2013 9:40pm

Re: MAC 8T or Direct Drive?

Post by kiwipete » Apr 07 2014 4:16pm

teklektik wrote: Thanks KP! That's actually a nifty plot - where did that come from?
The elevation chart came from Mapmyride.com. They also do a nice interactive one.

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teklektik   10 GW

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Re: MAC 8T or Direct Drive?

Post by teklektik » Apr 07 2014 5:32pm

Thanks!
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Build Thread: 2WD Yuba Mundo V4

Raged   1 kW

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Location: Melbourne, Australia

Re: MAC 8T or Direct Drive?

Post by Raged » Apr 07 2014 7:51pm

I've been doing a bunch of reading about discharge rates of batteries and possible combinations etc. for when I want to go lipo later on... I believe the size of individual batteries allows you to customise the layout within the bike frame better, but I guess step 1 is to get my shit running. Also reading alot about the different controllers since teklektik mentioned controller Rdon and efficiency (still so much to learn!!)...

Apparently the 3077 controllers are 25% more efficient (through less heat waste) than the 4110 controllers, however the 4110 controllers allow you to ramp up to 72v (upgrade path if I ever get the urge for more power... ).

"As an example, when pumping 25A of power through an authentic 3077, it will convert only 1.8A of power into waste heat, and a 4110 would produce about 2.2A, due to their high-quality materials having a low resistance of only 2.8 and 3.7 mOhm’s." <== http://www.electricbike.com/modified-hub-motor/

I've also emailed the store this morning via the contact us page (http://em3ev.com/store/index.php?route= ... on/contact ) to see what his recommendations are.

Judging by the info in the thread, If sticking with the MAC 10T, the initial battery choice 50V (14S) at 14.35Ah 3C (30Amps dischange) http://em3ev.com/store/index.php?route= ... uct_id=132 would be fine. It's only when moving to 8T (my original plan) that battery choice becomes different needing a higher C count (eg. 5C or 10C) and a beefier controller (12 or more FET).

So yeah, This is shopping list at the moment :

Controller : 9FET 30A (36-72V IRFB4110) (programmed down)
Motor : 255RPM loaded MAC 10T Motor
Wheel : Rear
Wheel Type : 700C Alex DM24 Disc
Throttle : full twist

Battery is still the same 14S 50V 14.35Ah 3C until I get a response from EM3ev.

Thanks for the great information so far.
Focus Black Forest 29er - MAC10T 14S Lipo - 50km/h, 50km range. (dead)http://endless-sphere.com/forums/viewto ... 91&start=0
Cube Reaction 29er Cyclocross BBS02 http://endless-sphere.com/forums/viewto ... =6&t=70549

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