Is the BBS02 a better option over a direct drive hub motor ?

[teslanv]

And DD Hubs ARE more efficient than Mid-drives, because they have no gearing losses.

Definably this is true when testing them at the moon and gravity is not an issue. :lol:
By your theory, feel free to remove the gear box of your car so to gain a lesser fuel consumption.

So by that theory, the Tesla Model S must be a dog, since it only has a single speed. If it only had some gears we could have better acceleration and higher top speed and do so more efficiently...

 

[teslanv]

Sure, If you are frequently starting and stopping, and imposing strong currents when starting on the DD hub, it will of course be less efficient in general. With a Mid Drive, you just stick it in low gear, so the starting current is much less than on a hub motor for the first few moments starting out. If you are constantly starting and stopping, then I would agree with you Kiriakos.

 

[leelorr]

This is why many BBS02 users are getting about 35 miles of range with only a 12AH battery.
Most hub motor users can not get any where near this amount of range on the same size battery because they have to use many more amps when they are "out of there best efficiency zone" (starting, accelerating from slow speed, climbing hills).
You should get better range from a geared hub motor than a DD also on a ride where you stop and start, or climb hills.

 

[ziltoid81]

In the end i think a bbs01/02 is the best solution, in both ways, reliability and efficiency....

Why reliability? More moving parts, more stress to the whole drivetrain.

After 6500km with the bbs01 i see it this way, you have less stress and consumption on the battery.......what is a major prize factor on an ebike.
A new chain.....cheap....one or two new sprokets......maybe one day a new nylon gear for the bbs, thats it.

After 6500km my whole drivetrain is still ok, not new but i didnt replaced a part so far.

Imagine how far you can go with all these power bikes with a mxus, cro or what not, when you install a bbs01/02.
Or in other words, how much less cycles you need for the same distance.

With my bbs01 350w i have serious problems reaching 15wh/km with no pedaling and 30kmh average in the city. (mainly 25-37kmh)
I have to push it hard and be inefficient to get 15wh/km, 99% of the time i am far far below that.

Then i read postings related to the "paper efficient" dds..25wh with pedaling....30wh......35wh......ok some are at another power level, but i think lots of riders dont see the paper efficiency in the real world.
Cause a dd cant be used in its efficiency sweet spot 99% of the time.......a middrive can.

So related to the prize, a dd and a middrive are even, what you save on the drivetrain needs to go in the battery.
The theoretical high efficiency of the dd exist only on paper......the middrive is efficient in the "real world".

Dont get me wrong, i also build up a powerful bike with lots of wh, a mxus and a 12kw controller, but i will keep my bbs bike for long trips and if i had to chose ONE bike.....i would go with the bbs bike.
I dont think i want to pedal a dd too far home, when something bad happens, with a bbs its like normal pedaling without noticeable drag or resistance.

A dd got other benefits than efficiency......you can dump lots of watts in these big motors.

 

[\/ampa]

There is nothing better than a DD hub.
You can get extreme efficency if you use a small DD hub motor (low cogging) and peddle always the first few meters without motor than when reaching >15 km/h let the motor help you. Also use regen braking in slip mode (low amp) this gives good efficency regen for downhills and regular stops.

 

[stuntmanmike]

Honest answer, the reading of the threads here has jaded you.
The bbso2 is a great unit & very dependable. In-fact I liked it so much I have 2 750w units, one on a hard tail and one on a full-sus. I ride single track almost everyday with one of the two and haven't had a problem..Knock...I try to be careful & not go big on jumps or drops as the spindles are square and will bend, as we've seen here. A splined Profile Racing style Bottom bracket would be, IMO, the greatest improvement to the unit & would open many doors & possibilities, maybe even a new sport, Up-hill mountain biking...just a thought.

 

[teslanv]

With my bbs02 bike, on a steep hill, I stick it in granny gear and power up the hill at 10-12 mph. On my DD MXUS, I fly up the hill at 25+ mph, because I can. True the MXUS will burn more watt-hours up that hill, but I enjoy it more as well. Efficiency is all about how you chose to ride.

 

[easyryder]

I have experience with the hub and the BBS02. IMHO the difference is in the terrain. If you are using your ride for commuting on nice paved roads with fairly flat terrain and plenty of battery power then you can get by with a hub. If you plan on spending much of your time riding off road climbing hills and mountains then a mid drive is definitely the way to go. I spend 80% of my time with my BBS02 riding off road typically climbing 1500 to 2500 feet in elevation. Shifting is not a problem as long as you anticipate the coming change in terrain in advance which can take a little experience. I have about 1500 miles on my BBS02 so far. If you want the best of both worlds, off road as well as on the pavement then the BBS02 is the only way to go!

 

[easyryder]

With my bbs02 bike, on a steep hill, I stick it in granny gear and power up the hill at 10-12 mph. On my DD MXUS, I fly up the hill at 25+ mph, because I can. True the MXUS will burn more watt-hours up that hill, but I enjoy it more as well. Efficiency is all about how you chose to ride.

Yes, but how long can you travel at 25+ mph before you over heat and burn it up. I have climbed mountains over 4000 feet in elevation in a little over an hour with my BBS02. If I want to travel faster I choose not to peddle, I use my motorcycle.

 

[rscamp]

At what current draw does the BBS02 operate most efficiently?

 

[teslanv]

The primary feature that turned me onto DD hubs was the ability to use regenerative braking. The BBS02 system will not allow regen because of the freewheels in the system. The same is true with geared hub motors.
On my ride to work I have several long hills with stops at the bottom or on a downward incline. On a mid drive or geared hub, all these stops consume brake component parts, and no energy is gained back from this. With my DD hub motor, not only do I have superior braking ability, but I also am putting some energy back into my battery. According to my CA, this is anywhere from 6-12% of the total energy used on my ride. I am not going to say that this balances out with the total energy used by my BBS02 because as I said before, I just ride faster with a DD hub, so its not really a fair comparison.

 

[easyryder]

At what current draw does the BBS02 operate most efficiently?

Good question! Rather than monitoring current draw with something like a cycle analyst I find it easiest to monitor cadence.

I have my BBS02 programed so any selected PAS level is 10% higher than the selected PAS level number. So if I am in PAS2 I am at 30%, PAS3 is 40%, PAS4 is 50% and so forth. With this in mind I will usually run my BBS02 in PAS2 or PAS3 and shift gears so my cadence is somewhere between 70 and 90. When ascending up steeper terrain I may step up one or two PAS levels maintaining my cadence the same. I seldom if ever use throttle and I always seem to have plenty of battery capacity.

I guess how you use the motor on your bike may have a lot to do with the why... My reason for using a BBS02 is strictly recreational. I go places that I can't go on a motorcycle, I enjoy nature and I get exercise.

 

[rscamp]

It was claimed here https://www.electricbike.com/bafang-bbso2-750w-mid-drive/ that the current at maximum efficiency for the BBS01 is around 11A. As a guess, pro-rating for the power difference to a BBS02 gives a current at maximum efficiency of about 16A. Can anyone confirm?

The motor should be most efficient and be able to run happily all day at the resulting electrical power (current at max eff. X supply voltage). Anywho, assuming this current is somewhere close, if the motor maxes out at 80% efficiency this is an output power of about (16X48)X0.8=614W. I think this would be about half the power required to climb a 10% grade at 20mph on a typical ebike. But climbing at maximum motor efficiency can be accomplished at some reduced speed with the right gear ratio. And this is an inherent benefit of a mid or crank drive with access to variable gearing...

 

[ziltoid81]

There is nothing better than a DD hub.
You can get extreme efficency

Thats the point, you CAN.......but in many situations you are not able to get the theoretical "paper" 85-90% efficiency, a middrive combined with different gears can do its 70-80% in nearly EVERY situation.

There is no "best" system for everything.

If you want to dump lots of watts and reach high speed and what not, go with the hub dd. Or if you know, you will ride in flat areas with no traffic, trafficlights, that stops you frequently.
If you want an always efficient, light setup, go with a middrive.

You have to consider what you want, you cant tell that this or that system is the best, it dosent work that way.
Maybe its the best system for your demands and your driving profile, but not for everyone.

Its a fact that everyone needs at least 2 ebikes. :lol:

 

[maxwell92036]

In my wattwagon with a 16 inch DD hub motor I think we achieve the best of both worlds. Great hill climbing ability with little wasted heat and at 48 volts plenty of top end (30 miles per hour plus). On similar terrain compared to my 3 Bafang mid drive units (one 750 watt model and two 500 watt models) my DD hub motor never gets as warm as my Bafang units even keeping the Bafangs in the proper RPM range with just pedal assist. I have had several rides where the Bafang mid drive got scary hot. Smaller motors even geared ones when stressed will get hotter faster than a larger motor.
Don't get me wrong, I like the Bafang units but there is a lot more to go wrong with them. I have had all of them apart to replace the clutch mechanism, and I think they could be made a lot better by having an external controller, and beefier components and a better bottom bracket assembly.
To me a DD hub motor is all about gearing and you can only achieve that by going to a smaller diameter wheel.

 

[\/ampa]

There is nothing better than a DD hub.
You can get extreme efficency

Thats the point, you CAN.......but in many situations you are not able to get the theoretical "paper" 85-90% efficiency, a middrive combined with different gears can do its 70-80% in nearly EVERY situation.

There is no "best" system for everything.

If you want to dump lots of watts and reach high speed and what not, go with the hub dd. Or if you know, you will ride in flat areas with no traffic, trafficlights, that stops you frequently.
If you want an always efficient, light setup, go with a middrive.

You have to consider what you want, you cant tell that this or that system is the best, it dosent work that way.
Maybe its the best system for your demands and your driving profile, but not for everyone.

Its a fact that everyone needs at least 2 ebikes. :lol:

Oh oh, now you all shine the light on the low efficiency of DD hub in low RPM which especially on hill climbing are big problem.
Yeah thats the only downside of them. (except for using rare earth magnets)

But like maxwell92036 pointed out its a matter of gearing and hub motor size to be a good efficient hill climber.

So buy at least a 1000w rated DD hub and lace in <= 20".
Also choose a system top speed of 50/60 km/h and climb hills with at least half of that. Slip regen charge on rolling down the hill at reasonable safe speed. The system efficiency will be at least same as a mid drive.
If you choose a too small DD hub and your controller can not put enough amps out to hold enough speed to be efficient on hill climb than your ebike is a fail.

 

[maxwell92036]

my DD hub motor never gets as warm as my Bafang units even keeping the Bafangs in the proper RPM range with just pedal assist.

The only way to do a reliable measurement is to implant a K-type thermocouple which will be in contact with the windings of that hub.
Comparisons by touching the hub cover is not reliable.

At Bafang & BEWO Mid-drive KIT, the temperature of the motor it self is more realistic, the windings are directly attached over the motor body.

Could be but the mass of a direct drive hub motor acts as a heat sink. I think Bafang on their mid drive motor needs to move the controller outside of the motor case for cooling purposes and to make repair to the controller easier. It's a nice clean slick unit but having two heat sources in a small area is asking for trouble in my opinion. same with a hub motor of any type. I think the controller being outside the hub is a better design.
So do you think that my hub motor is heating up as much as the Bafang mid drive?

 

[eMax]

To put it simply, think of heat as a measure of inefficiency. Friction and heat loss is converting the input energy into alternative forms. A good electric motor will have a good thermal efficiency and won't produce much heat.

Considering this in real world a real world example. The BBS02 mid-drive gets barely warm after a 20km commute which I do 3-5 times per week. The average speed is consistently 25km/h. On my geared hubs (Bafang SWXH, MAC 10T) and direct drive (9c) the motor is always hot to touch with the same commute maintaining the same average speed (the SWXH is a tad slower).

Because of gearing the mid-drives never work as hard and get more watt-hours per kilometer. I have begun gathering data with this comparison in mind. Of-course enjoyment level is not a huge factor in my tests. This is commuting with efficiency in mind.

 

[darth_elevator]

I enjoyed reading through this thread and seeing the differing viewpoints.

It’s a fact that everyone needs at least 2 ebikes. :lol:

This made me chuckle. I have both a BBS02 and a DD and like them both for different purposes. After having both, I wouldn’t want to have to choose just one.

Never gonna be a clear-cut answer…

There is no "best" system for everything. …
You have to consider what you want, you can’t tell that this or that system is the best, it doesn’t work that way. Maybe its the best system for your demands and your driving profile, but not for everyone.

That’s one reason why I enjoyed reading all of the comments on this thread -- hearing about people’s specific needs and what they have found that best meets their needs.

….completed weight, ease/quality of installation plus battery C rate being much more important consideration than any perceived “reliability” issues.

Good points. My DD wins hands down on ease of installation. Once I decided where I was going to place all of the components, it took less than half an hour to install the DD. The BBS02 took 2-3 hours (although the second install when I moved it from one bike to another did go a lot faster). On the other hand, my BBS02 wins hands down on weight of installation. For batteries, it's a draw -- I purposefully went with 48 volt systems on both, so I can use the same batteries in both.

…. 34t chainring. THE TORQUE IS INSANE!!!! There is no hill I could not climb….

… If you like to tinker, have fun experimenting, don't mind replacing chains and cassettes, and want a super versatile and efficient setup that does the most with the least watts - MID DRIVE!

…. BBS02 rides like a motorcycle and hub motor rides like a scooter. For the BBS02, you'll need to check your bike regularly because of the extra strain on the drivetrain. …

Mid drive is irreplaceable for mountain bike, especially full suspension, I think. …

For mountain biking, BBS02 wins for my needs. I’ve taken my BBS02 on single track rides that I wouldn’t even dream about taking my DD on – for several considerations, including roughness of the terrain, ride length, and amount of elevation gain. But for riding around the neighborhood -- slightly hilly terrain and paved surfaces -- DD wins due the fun factor of the acceleration and speed -- we've taken rides with both and the BBS02 can't keep up.

…. If you need help about discovering details of the mystery brand which is about to release a mid-drive at 750W? I am interested to assist at this hunting for additional information.

Kiriakos, I’m an interested in learning more. A friend told me a few months ago that Bafang was coming out with a new mid-drive, but I had not heard that it might be a different brand or company.

If the [BBS02] controller cooks, run a sensorless external sine-wave controller, easily found for under $100.

Just built my first bbs02 and already had to bypass the controller and use my external lyen controller.

Although my stock controller is still running fine at 1000 miles (knock on wood), I’ve thought about installing an external controller so I don’t have to worry any more about the stock controller failing.

Wineboyrider, would you be willing to post a link or the name/model number of that Lyen controller you use and also whether you recommend that model?

Spinningmagnets, are there any specific controllers that you would recommend? I don’t have any background in electronics, so I’m not exactly sure I’d recognize an external sine-wave controller if it hit me in the face. 

…. The weakest point on the mid drive is the chains, so if you chose good quality chains and use guides to make sure you have no derailments then the mid drive will be more reliable if you use less then 1 to 1.5kw peak power. Any more then that and bicycle chain and components may start having a short life.

I’ve had the same experience. I didn’t realize this before I got my BBS02, and perhaps it might have dissuaded me from getting a BBS02 if I had heard about it before. But this has been manageable. Using a good quality chain, keeping an eye on chain wear, using a chain guide, and carrying a spare chain have, for me at least, been a very small price to pay for the BBS02’s excellent performance on demanding single track.

…. had to completely disassemble the [BBS02] motor. I was able to repair it, and re-greased it gratuitously when reassembling the motor ….

Teslanv, I don’t consider myself particularly adept mechanically (a friend helped me install the BBS02). How difficult was it to disassemble, re-grease, and re-assemble the motor? I have 1000 miles on it. Would you recommend a re-greasing at this point or should I leave it alone since it’s still working fine?

The bbso2 is a great unit & very dependable. … I try to be careful & not go big on jumps or drops as the spindles are square and will bend, as we've seen here. A splined Profile Racing style Bottom bracket would be, IMO, the greatest improvement to the unit & would open many doors & possibilities, maybe even a new sport, Up-hill mountain biking...just a thought.

LOL @ up-hill mountain biking as a new sport. That’s what I love about my BBS02 – I always feel like I’m going downhill, even when I’m going uphill!  Thanks for the comment about square spindles not being as strong as splined. I hadn’t thought of that before, although I normally walk the bike over bigger drops anyway, but I agree that splined cranks would be a huge improvement.

I have experience with the hub and the BBS02. IMHO the difference is in the terrain. If you are using your ride for commuting on nice paved roads with fairly flat terrain and plenty of battery power then you can get by with a hub. If you plan on spending much of your time riding off road climbing hills and mountains then a mid drive is definitely the way to go. I spend 80% of my time with my BBS02 riding off road typically climbing 1500 to 2500 feet in elevation. Shifting is not a problem as long as you anticipate the coming change in terrain in advance which can take a little experience. I have about 1500 miles on my BBS02 so far. If you want the best of both worlds, off road as well as on the pavement then the BBS02 is the only way to go!

Easyrider, my experience matches this. I’m about 500 miles behind you, though. LOL. Like you, many of my climbs are 1500 to 2500 feet in elevation gain; many are 4000, and I’ve also gone on 3 or 4 5000+ climbs. With a 34T chainring, the BBS02 has performed wonderfully.

The primary feature that turned me onto DD hubs was the ability to use regenerative braking. …. superior braking ability, but I also am putting some energy back into my battery. According to my CA, this is anywhere from 6-12% of the total energy used on my ride.

Like you, I like the superior braking I get on my DD. Thanks for sharing your data I had no idea that real-world results were as high as 6 to 12%. That’s great to hear.

… the AFT EMAX is probably the best mid drive kit out their now…

Wow, I had not heard of this mid-drive before. I just looked it up and really like it. I wish I could afford it.

 

[teslanv]

Disassembly and regreasing the BBS02 was not all that big of a chore, really. And I think I vastly improved the longevity of my motor by doing so. I would definitely recommend it.

Regen battery recovery will depend a lot on your terrain and riding style. So far my rides have been pretty short, so it's hard to say what the real average is. I would guess in the 7-8% range. But this added range is just icing on the cake. The main course is better braking with a DD hub & Regen.

 

[darth_elevator]

Ok, thanks very much for your advice. I'll give it a shot. Is one kind of grease better than another? I have some Super Lube on hand.

 

[teslanv]

Ok, thanks very much for your advice. I'll give it a shot. Is one kind of grease better than another? I have some Super Lube on hand.

Right here, waaaaaaay back on page 2 of the finding faults & fixes page...

http://endless-sphere.com/forums/viewtopic.php?f=28&t=58898&hilit=BBS+finding+faults+fixes&start=25#p881674

 

[darth_elevator]

Perfect! Thanks very much!