Complete switch - Cheap crankdrive MTB

Hi all,

After my latest experiences with lipo-driven hubmonsters, I have decided to go low power high efficiency Li Ion. Enter crankdrives.

I have purchased this bike: http://www.ricardo.ch/kaufen/sports/radsport/elektrovelos/24-gang-elektrovelo-mountainbike-trettlagermotor-panasonicb/v/an718652344/



It should arrive next week. I will post a review here. It has a Suntour front fork on it, which will be the first thing to be replaced, together with the brakes.

Additional links / reviews:
http://www.pedelecs.co.uk/forum/electric-bicycles/8775-bofelli-crank-shaft-motor-challenge-bosch-drive-system-waste-time.html
http://bofeili.en.alibaba.com/product/247563456-209381840/BFLEM36_001_Brushless_DC_Electric_Motor.html
http://www.bmsbattery.com/central-motor/321-ebike-central-motor.html

And here on ES:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=26995

Bike specs

First pics of the bike. Note that I already made some changes:

• RST fork replaced with 2009 Boxxer with 20mm through axle, spin doctor, 36 sepim 2.0mm spokes, Halo SAS 26" rim, and Maxxis 2.5" High Roller front tire. Mudguard is Carbon Fiber fixated with zip ties. 210mm rotor with BB7 mechanical brakes in front.
• Rear tire replaced with Schwalbe Marathon Plus MTB 1.9". I tried a large 2.5" tire, but it doesn't fit within the frame. Probably a 2.1" or 2.25" tire should fit.
• Original bottle battery was fixated to the frame using the drink-bottle screws. I replaced this with the triangle bag, which has the bottle battery in it.

More stock details:

• Mechanical Tektro brakes in the rear (fading already during a longer dh trail)
• Cheap Shimano SIS group (skipping already when going uphill)
• E-brakes to drive the Tektro in the rear and BB7 in front. They work well in disconnecting the power to the motor when applying the brakes.

Last weekend I tested this bike going up and down the mountain behind my house:

Coming from a non E-bike, the Bofeili gives me a nice edge, and it still feels light. I am not trained, and obviously have difficulties dealing with the small mountain behind my house. Elevation is 438m over 7.78km. Last time I did this with a push bike it took me 1 hour. Now I was able to do it in 44 minutes, with an average speed of 10.6kmh. Very nice.

Furthermore, the BB drive and the battery in the lower part of the triangle gives the bike a nice feel and it feels light.

So, I used only the lowest power assist when climbing this hill. In the graphs, you can also see that I did exercise a lot, keeping my heart rate between 150 and 180bpm. Therefore, I conclude that this bike gives me just that little extra to make exercising with the bike more fun, extending the range of my biking possibilities, without taking away the element of physical exercise. Having a light but power-assisted bike is fun. And the bike is light enough to climb hills. I did say the bike feels light, right?

Some of the disappointments came when I took the trail downhill again. Here I find that I have been spoiled by my previous FS frame with full hydraulic brakes. The Bofeili, despite having the Boxxer in front, just cannot keep up. The rear bucks at every wobble, the brakes are fading, and therefore my speed is much much lower than I am used to when going downhill with any FS setup. Maybe it is just my inexperience as well, but this bike is not for fast DH rides.

Furthermore, I use the bike for my daily commutes. Here is what I found:

Coming from a Cromotor powered E-bike, the 250Watts of the Bofeili are underwhelming to say the least. Speed is 30kmh max, despite the connector that should allow for 45kmh speeds. Acceleration equals my grandmother's bike with my grandmother biking, and range among the hills in low power just falls short of 30km. For a commute with a business suit, too much exercise is needed to get to work. Adding a 36V low winding high speed but light Mac in the rear is definitely an option I am currently considering.

For commuting, the hardtail still gives me a sore behind. Definitely also considering a suspended seat post.

to be continued...

Not needed anymore.

The Bofeli has a very strange geometrie and the bike is not worth half the money.
There is a very long thread in the german Pedelec-Forum discussing all the problems and issues of this motor and frame. Most people are not happy with it.

Better get a bafang crankdrive and put it on a high quality bike. That will be the cheaper and much better option, and you can easily go for a Fully.

--freeride-- said:

The Bofeli has a very strange geometrie and the bike is not worth half the money.
There is a very long thread in the german Pedelec-Forum discussing all the problems and issues of this motor and frame. Most people are not happy with it.

Better get a bafang crankdrive and put it on a high quality bike. That will be the cheaper and much better option, and you can easily go for a Fully.

Click to expand...

Thanks, I hear what you are saying. I will start reading that thread. Bike is coming my way anyway, and what I've read, there will be lots to improve.

Update: from page 35 of the german thread:


Further reading of that thread revealed at least 4 persons who bought something similar (Joe23, grosserschnurz, velorelax, bangbang). They are not all negative and some are really positive like this post. At least one of them replaced the controller with another one. As far as I can tell, if the motor is turning, the cranks will turn with it. And the topspeed of the motor results in a too high cadenz (>120 rpm), therefore, it may make sense to replace the controller with a programmable one to allow for a maximum cadenz of 90 rpm by limiting the actual speed as appropriate.

I have a 37V Lyen sensored 6FET mini-monster here, that should work in combi with my CA v3 with peak currents up to 30A (battery side 1kW peak, phase current maximum 75A). I will probably have to put another battery in parallel to get to the necessary currents as it looks like the BMS is limited to 15A. Furthermore, another thermistor-implantation is in the planning.

Continuing reading the long thread. Now at page 63 of 73..

UPDATE:

Due to various stupidities my side (car broke down, causing a delay in picking up packed bike from post office, then bike was sent back to seller by post, and fortunately seller sent bike back again to me) there was a month delay in getting the bike in house. It is here now, I assembled it, charged the 36V 10Ah bottle battery, but the battery did not provide any voltage, despite 5 nice bright LEDs burning. I agreed with the seller that we would do a battery switch, so I sent the battery to him, and I am waiting for my new battery. So far, good service from the seller.

Bike looks nice, and after switching to my Boxxer, it looks gorgeous. Hopefully, I can start my review this weekend.

Second post updated with actual specs of the bike that I now have in my possession.

Third post updated with my experiences.

Good honest review. That's something we need of all these new premade bikes. Especially since you have Cromotor experience to draw different conclusions from.

OK, so where to take it from here?

First, I don't want a heavy (10kg) hubmotor anymore. And I don't want to pull any huge currents, and I want to stay at 36V Li Ion batteries with internal BMS thingies that can deliver maximum 15A. However, I do want to go faster (45kmh) and have a full 30km range (commute roundtrip).

The Bofeili on 36V 10Ah only makes the 30km in the lowest power settings. This feels like 100-150W max to me. Anything close to 250W (full power) depletes the Battery halfway my commute back home (3/4 of my roundtrip, or around 22km). So the idea is now to add a high speed Mac on another battery to provide some added top speed.

With a 6T Mac from Paul at EM3EV, I should be able to hit 40-45kmh with "only" 36V. The Mac is less than 5kg, and I will lace it into a 24" Halo SAS rim that I have lying around here. Total weight of the bike will thus increase 5kg (Mac) + 3kg (extra battery) + 0.5kg (Lyen sensorless 6FET 4110 minimonster with wiring + 3speed switch). The Sensorless controller will be driven by an additional PAS sensor and a 3speed switch, and will be limited to 15A.

Paul sells the 6T only with added temp probe. However, at 15A I don't think that the MAC will be at high risk for burning. I will use the Bofeili system through the gears to get me up the hills at low speed. I will use the Mac to get to high speed where it is possible. Best of two worlds, or so I hope....

6T Mac has been ordered and shipped. Will take a couple of weeks before it arrives. In the mean time I will continue to commute on the Bofeili. It is really quite convenient when you get used to the low speed.

why you don't want cromotor anymore? do you have to lift the bike?

Mainly, Because there is no way to make it legal here in Switserland. There are some other reasons as well. One is that using 36v on a cromotor is like putting a 12cylinder Ferrari motor in a VW beetle.

oh, it's all about legality? Can't you just have an insurance?

cwah said:

oh, it's all about legality? Can't you just have an insurance?

Click to expand...

Insurance won't cover anything if the bike is not approved. For anything faster than 25kmh and up to 45kmh, we need an officially approved bike, showing that it is approved using a yellow numberplate. This yellow plate also means it is insured.

Had a nice discussion with Paul from EM3EV. He thinks that a 6FET is not enough for the high turn Mac, and that a sensorless controller does not work well. Now I still have a Lyen 12FET 4115 sensored controller here, so I can use that one if my 6FET 4110 sensorless brakes down. Furthermore, he does not expect 500W to be enough to get to 45kmh. Fair enough. However, things go into the high amps again, and that is exactly what I wanted to prevent.

So now the plan is as follows:

1. Start with the 6FET sensorless at 36V and 15A max. If that does not work well,
2. Continue with the 12FET sensorred at 36V and 15A.
3. Whichever one works, I will start at 15A. May need to increase, but let's see what the 15A version in combo with the Bofeili does, first.

hjns said:

Had a nice discussion with Paul from EM3EV. He thinks that a 6FET is not enough for the high turn Mac, and that a sensorless controller does not work well. Now I still have a Lyen 12FET 4115 sensored controller here, so I can use that one if my 6FET 4110 sensorless brakes down. Furthermore, he does not expect 500W to be enough to get to 45kmh. Fair enough. However, things go into the high amps again, and that is exactly what I wanted to prevent.

So now the plan is as follows:

1. Start with the 6FET sensorless at 36V and 15A max. If that does not work well,
2. Continue with the 12FET sensorred at 36V and 15A.
3. Whichever one works, I will start at 15A. May need to increase, but let's see what the 15A version in combo with the Bofeili does, first.

Click to expand...

That will be fine for 45km/h max. with pedaling... But isn't that illigal like the cromotor?

--freeride-- said:

That will be fine for 45km/h max. with pedaling... But isn't that illigal like the cromotor?

Click to expand...

Not when I have it evaluated and approved at the local authorities.

The main limitation of the Cromotor is that it does not really move at 36V and <1kW. The 1kW is the real power limit defined in local (Swiss) regulations, and to have the bike approved it needs to stay below the 1kW and below 45kmh. The 6T Mac is the lightest motor (<5kg) that I could find that moves me to 45kmh at 36V, probably at 750W. With the Bofeili doing 250W max, that keeps me legal.

ezee would be lighter at 3.7kg and still able to do 45km/h

why 36v limit by the way?

cwah said:

ezee would be lighter at 3.7kg and still able to do 45km/h

Click to expand...

I was not aware of that. The ebikes.ca simulator gives only 30-35km/h for the ezee or ezee v2 at 36V. Only when going up to 48V can you expect 40 km/h, according to Grin.

Why can't you increase your voltage?

hjns please be careful with that fork & frame combo! I You may already know this, but long-travel triple-crown forks such as the Boxxer typically put more stress on the headtube, and if the bike wasn't designed with a strong or reinforced headtube it could break off. Just FYI, coming from someone into mt biking for 20 years.

voodoosand said:

hjns please be careful with that fork & frame combo! I You may already know this, but long-travel triple-crown forks such as the Boxxer typically put more stress on the headtube, and if the bike wasn't designed with a strong or reinforced headtube it could break off. Just FYI, coming from someone into mt biking for 20 years.

Click to expand...

Good point. Are you saying the 200mm travel puts more stress on the headtube because of the increased travel, changing the angle of attach to the headtube? If so, I will measure the original fork, and then find me a fork with the same travel. Probably something between 80 and 100mm. Or is it because of the top crown also pushing on the headtube from above? Again, moving to a single crown fork would solve that, right?

Question, what is the actual experience with this "mismatch"? You must have seen lots of stuff in 20y of MTB...

cwah said:

Why can't you increase your voltage?

Click to expand...

I may end up with 48V....