AM dual motor = bafang middrive + rear hub motor

John Bozi

100 kW
Joined
Apr 8, 2013
Messages
1,892
Location
Brisbane, Australia
This is my build blog where I started by asking should I use my old heavy bike or new carbon bike for a cheap chinese kit.

What happened over the many pages was that I was convinced to go with the cheap bike with the cheap kit.

However that went to cheap el crapo land and then I paid some real money for a decent kit and a new Hasa bike. You can see it unfold or you could just jump to where my hasa FS 4065 road bike is by jumping ahead.

Keep cool and check out my channel of how my bike is running.

Also the electric bike is now for sale.
10526081_10152600407674845_5283644839395750145_n.jpg

If I had to build this bike again (not taking shipping into account on most items)
This includes:

$580 AU 4065 motor http://www.crystalyte.com.au/ you can have the 26" rim and spokes/nipples and a couple of used hookworm tyres that have lots of life in them.
$36 Au 7 speed freewheel 11t-? cassette http://glowwormbicycles.com.au/store/e-bike-parts-and-accessories/freewheels/dnp-epoch-screw-freewheel-7-speed-11-34t-ebikes
$175 US 40 amp controller http://www.ebikes.ca/shop/ebike-parts/controllers/c7240-nc.html
$150 US cycle analyst v3 DP http://www.ebikes.ca/shop/ebike-parts/controllers/c7240-nc.html
$20 US throttle with regen button http://www.ebikes.ca/shop/ebike-parts/throttles/t-htwist-b.html
$40 main torque arm (heavy duty) http://www.evworkslab.com/products/rear-bolt-on-torque-arm
$50 drive side http://www.evworkslab.com/products/rear-bolt-on-torque-arm these are both quite heavy for shipping.

$1300 US for the bike http://www.cyclingdealusa.com/HASA-Mountain-Bike-p/xc1d11.htm = you can have all the parts to convert it back to a normal bicycle.
$65 AU zee short cage derailleur http://www.wiggle.com.au/shimano-zee-m640-shadow-plus-rear-derailleur/?lang=au&curr=AUD&dest=27&utm_source=pla&utm_medium=base&utm_campaign=au&kpid=5360535777
$85 dnm shock (save space without an oil reservoir) but you can have the original spring shock that came with the bike too if you don't need the space.
$230 race face chain ring custom shortened cranks and pedals
$50 dx32 19" rim
$80 black sapim spokes http://glowwormbicycles.com.au/wheelbuilding
$6 extension valve to pump up small wheels http://www.ebay.com.au/itm/MOTORBIKE-MOTORCYCLE-BIKE-TYRE-VALVE-ADAPTER-90-DEGREE-EXTENSION-NEW-/161235669721?pt=AU_Motorcycle_Parts_Accessories&hash=item258a6512d9&_uhb=1
$100 downhill or thick and tough tubes and tyres = high roller creepy crawler.
$65 wide downhill handle bar boo bar http://www.chainreactioncycles.com/au/en/truvativ-boobar-riser-bars/rp-prod67690?utm_source=Google&utm_medium=Shopping&utm_name=Australia&gs=1&gclid=CP61_Z__7b8CFdgRvQod510AGw&gclsrc=aw.ds

$3000

Negotiable - if needed:
Power supply $140 http://www.ebay.com.au/itm/SKYRC-eFuel-30A-540W-Switching-Dual-Output-DC-AC-DC-30-amp-Power-Supply-SK200013-/181263160222?pt=AU_Toys_Hobbies_Radio_Controlled_Vehicles&hash=item2a3420539e&_uhb=1
$170 2x ichargers 106b to balance charge safely
$700 6x6s & 2x3s 5.8AH turnigy http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14715
$50 2p harnesses

$1000

As you guessed it $4000 all up. Yes it isn't brand new but take into account all the false starts (stuff spent on things that didn't work) and all the shipping on individual items and all the work to customise all this to work together and I'd pay the same amount again.


For most of the above the shipping costs were not included.
 
pendragon8000 said:
Kepler did a sweet carbon geared hub build...
http://endless-sphere.com/forums/viewtopic.php?f=6&t=47139
he did add a small torque arm though.

His bike looks sweet as. I think I should have mentioned that I plan to use it on mountain bike tracks. It might help to show you what the bike looks like and the way I ride it. This video shows me going down a 5 minute single track which I bought the ekit for, to hopefully pull me up it.

[youtube]BrKt-vjbeoE[/youtube]
 
Even if carbon can hold (and it prob will) there's not much advantage of saving that little weight. Once you add the motor and batteries it will be close to 20kg anyway. So 3~5kg won't make a huge difference.

Try converting the tank, chances are you won't like the hub off road :wink: so you'll end up with a nice commuter instead :mrgreen:
 
Another vote for the tank. Chances are, you are adding at least 20 pounds to the bike, making the light weight of the carbon meaningless. I often tell newbies, don't ruin your favorite bike with a motor.

First time building an ebike, it's always best to do some experimenting with a nice steel frame. With the assist, it will have inertia, but pedal like it weighs 10 pounds.
 
One more vote against this idea. Any Carbon advantage is lost the moment you install motor, controller and batteries. Strong aluminum and good torque arms = fun!
 
I'd plan to convert the carbon bike since the total package would be that much lighter, but I'd get the kinks worked out on something cheaper first.
 
tank. and a mac 10 turn 18-24s = fun
 
I will go the tank then!

The whole Ebike thing seems like a double edged sword. I love riding my carbon bike but hate doing 30 minute mountain climbs. That's what got me into going ebike. But as said - I probably won't enjoy riding down on a heavy bike especially a tank.

Looks like I got side tracked - bought it for one reason - use it for another. I think the tank will be fun on bike paths anyway. :)
 
You CAN and usually DO build carbon fiber stronger than steel. But durability depends not just on strength but on TOUGHNESS. A carbon fiber bike frame is the strongest house of cards you'll ever see. The great vulnerability of composites is side impact, there's almost an eggshell quality. They don't like vibration, though they're not automatically vulnerable to it. Then there's the question of whether your specific frame might have suffered from some pinholes or other undetected voids that make it weaker.

I'll say you just take the fun out of the build when you go with an additional wildcard. Something cheap is always best when it's an experiment.
 
for full-disclosure: I have had no personal experience with carbon frames. That being said, I would not be concerned with a downhill carbon frame, as they are very robust...when used with a medium power system (750W-1,000W), or less (like the 500W you state).

If you were using a high-powered system (1,000W+ with NO soft-start throttle), and wanted to use a super-light road-bike carbon-fiber frame, I would not recommend it at all.

I highly recommend you get a Cycle-Analyst to limit the amps.
 
research broken carbon bikes. IMOP no to electric bike torque and speed on a carbon frame. It can be done but at your own risk, with PAS and no regen it may last a while but I personally like a reinforced steel frame non suspension. but just my thoughts, Try it and let us know from time to time how it is holding up under all conditions. anyway keep the GRIN going!!
 
What a great forum, lots of feedback and everyone is so positive. thanks!

I have been in back forwards emails with the HK guy I'm getting it from Ebay. Also so far I am very happy that there are real people out there to customize things.

I was negotiating a battery shape which I was suprised that he would do for me, because it was kind of post purchase. Unfotunately he can't get the triangle under 11cm thick, but it will be roughly 40 40 20cm, so I am still hoping that this will not affect my knees and pedalling. I highly doubt this would fit the carbon bike anyway as it is my "dream" bike that I bought for many reasons one being size.

so it must be the 19" ht tank. My greatest concern with the tank are the rubbish vbrakes. I don't even have the choice for the back of putting them on but am considering upgrading the front to having them at least.

One question with ebike. Why do you have brakes to turn off the motor if you are using throttle? Surely we are not stupid enough to be pulling on the throttle and brakes at the same time. Or is this for the pedelec system?

My plans are to peddle normally on flat and downhill but to use my thumb throttle to pull me uphill.
 
width:
i have 2 bikes both 12cm width battery boxes, absolutely no problem and if anything it is nice to be able to rest leg afainst it when leaning or whatever.. no hindering of pedaling.

ebrake cut off:
sometimes there are throttle or controller glitches that cause acceleration when there is no throttle being applied, it is rare but does happen. I recomend putting a micro switch under the leaver or reed switch and magnet. just on the rear so you can power slide a bit (low power not so much but have a crack)
 
I never use brake switches running up to 2kW DD motors. if your brake on that wheel is unable to stall the motor, you need a better brake, IMO. Yes, I've had wet throttles go wide open but DD motors don't make that much torque under 2kW - they can still shoot across a room when you're not sitting on it but the brake switch isn't handy at that moment anyway.

Cheap levers and added wire to run I just never found the need for it.... Unless, you're doing regen which I don't usually endorse either. Too much trouble (clamping torque arms) for little benefit in my terrain. YMMV
 
Safety first? If you're sitting at a red light and your hand isn't on a brake lever you're lacking motorcycle safety training. How 'bout the flip side? You're going through the green light at the intersection and a speeding car runs the red and will hit you if you don't keep moving - too bad that cheap switch engaged at the worst possible moment, eh?

Nothing wrong with good engineering but I see time and time again how stuff that becomes so complicated, clean, simple execution suffers. Large bundles of cheap wire and switches from China don't instill me with confidence.

No need for clamping torque arms on non-regen, under 2kW DD. Good for you if you can do it properly but I can find much more important things to budget my time and resources for. Like motorcycle traffic safety, for example....
 
I get the picture that those brakes are a maybe.

I have another question I should have asked here before I started and maybe help me start a future project.

How powerful does the motor have to be to get me (80kg) up a mountain without pedalling? The mountain is maybe a hill for you, about a 30 minute no stopping pedalling ride up hill.
I don't need speed going up just want it to take me up and do it without the motor having problems. I enjoy the scenery! I basically want it to pull me up once or twice per charge. Once the motor is worked out then what kind of battery do I need that matches that battery best?

thanks again, maybe this should be a new thread let me know if so.
 
This question can lead to a long discussion. The typical hubmotor kit is aimed at street riding, with grades typically not much over 5%, and can tackle 10% if it must. If you have less steep trails, then no problem. If you want to ride up 15% grades or steeper, then you have a problem with a hubmotor.

What happens is that as the grade steepens, the 800 watts or whatever is not enough to keep the speed up. At some point as speed at full throttle drops, the motor begins to get less efficient. This begins a bit of a death spiral where as you get slower half your power starts heating the motor instead of just 20% of it. So the 800w is now 400w, which makes you slower, which makes the motor make even more heat which makes you slower which......... Till at some point while you are riding 5 mph or less, the motor burns up.

How do you fix this? Three things to do can help.

One obvious one is gear down. Only one way to make a hubmotor shift to a lower gear, that is use a smaller rim. So some rebuild bikes to take 20" wheels, or use a BMX bike.

The other obvious one pour on the power. Even with the 26" wheel, serve up 2000 watts instead of 800 and you will go faster up that hill. This can work quite well on grades 10% or less for sure. Often part of the way to do it is to increase voltage. Just going to 48v instead of 36v gets you about 300w more, and might be all you need to get up 10% grades just fine. There are oversize motors out there that tolerate 3000w easily, and with 3-4 hp you can climb some hills with pretty good speed, keeping the motor in the more efficient rpm.

The last, somewhat less obvious method is to use a slower wind motor. This motor is designed to go slower, and therefore has a better tolerance for speeds under 15 mph. It costs you top speed, and a really extreme slow motor may require you to increase the voltage a lot, to avoid having a bike with a top speed under 15 mph. The slow motors can be hard to find, but one that can be bought easily is the Mac gear motor from cellman.

http://em3ev.com/store/index.php?route=common/home

The 12T version of the motor will get up hills with less heat waste than the faster motors.

My own approach has been a combination of the more power approach and the slow motor approach. I have used direct drive motors of the 9 continent brand, in their slow and very slow winding models. The 2810 model run on 48v goes about 20 mph max, and climbs 15% grades just fine with light pedaling. My favorite though, is the extremely slow 2812 motor, which I run on 72v. 25 mph top speed, but able to climb crazy steep hills for a mile or so before melting down. By limiting the wattage to 1500w I have no problems, but I have at times doubled that to 3000w. At 3000w, with a 72v 40 amps controller, you pretty much never pedal unless it's up a grade of 30%. But you do have to watch it how long you climb really steep grades. I have several motors, and often have one running while another waits for melted hall sensors to be replaced.

Batteries for dirt riding tend to be RC lipo type in the last few years. We want power, and we want it light. The possibility that the batteries might catch fire is not part of the decision, but once you do go for RC lipo, you want to be very careful how you use them, store them, and charge them in a place where a fire won't result in dead people. You don't just plug in and go to sleep with lipo.

Other types of battery might be OK, but the weight may result in a bike that handles less nice. It depends on the difficulty of the trails you ride, how much handling matters. In the rocky mountains where I live, I try to have the bike handle as good as I can afford. So I run lipo.

Here is a pic of my dirt ride. It's a cheap bike, but I upgraded both shocks to make it ride tolerable. I carry the batteries on the front to keep the handling good. Dogmans Dirt bomber. small.jpg

Link to video, I have quite a few vids on Y tube, showing how it can get up a rocky hill pretty good. With heavy pedaling, it finally gets stopped at about 20 degrees. Not sure what % grade that is, but it's rock crawler 4x4 or mine roads.

http://www.youtube.com/watch?v=AfwdkfNZ7RQ
 
thanks dogman, that's a ton of info for my brain to try to digest.

Your ride up that mountain was impressive although the angle doesn't really do it justice. I find you need to put tripods near trees that give a sense of what is vertical. I do however really like that other link you gave me, first thing I really like is the triangle bag for a 17" bike which is the same as my carbon bike.

What price range are we looking at here to be climbing this mountain?

So basically I should have stayed away from hub motors? Ive read many places that the mid drive is the go for hill climbing. I was scared off by the complexity of them, they just look like so much can go wrong and I cant imagine how I would keep out the dirt.
 
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