Can we buy the 50amp controller? Or 72 volts?

[madnut]

I see that the Luna Ludicrous has an in house built 50amp bbshd controller, can we sign some sort of waiver and buy one?
Also I wounder is Luna working on a higher voltage controller for the bbshd. There was a recent Reddit post of adopting the cyclone 40A 72V controller to the bbshd and the results looked very promising, much more so than the high amperage 65+ attempts. https://www.reddit.com/r/ebikes/comm..._40a_external/

[Rodney64]

At this stage its just for customers who buy complete builds.

[madnut]

But do you plan to sell it separately at some
point in the future?

[SDharlie]

That's a crappy incentive to sell only complete builds. Kinda goes against everything Luna has stood for so far - I was under the impression that Luna was all about "DIY"

[JPLabs]

I'm sure it's not that simple. Supply is undoubtedly very limited. Cost of a small run is quite high, or real high if tooling had to be bought. Note that the heat sink housing is new and different; those die cast tools aren't cheap. And from the photos, it looks like it might even be machined, not cast, at this point anyway. That's not cheap, either! I wouldn't be surprised if the piece cost for a small run was several hundred dollars. So, it might not even make sense to sell them individually; they might need to sell full bikes just to make the business case work.

It is clear that there aren't enough of these controllers for everybody now. Who should get to use the limited supply for builds, Luna, or everybody else? Luna, of course.

Erik has proved over and over that he's not out to screw over builders and customers, and that he's strongly in support of DIY, so come on, let's give him the benefit of the doubt, here! Trust his intentions - don't read any animosity into them, that's crazy. We don't know the whole story. But I'm sure it would make sense, if we did.

We should just be happy he developed this controller, rather than upset that they aren't easy to get.

[CraigAustin]

Bafang apparently dropped the hammer on resellers for hotrodding HDs, but looking at that video it appears the horse has left the barn.

[spinningmagnets]

Easy to criticise from the Monday morning armchair. If you are willing to buy one hundred units (minimum order quantity/MOQ), you can get just about any product you want from China.

I am sure there will be several high-amp controller options available to customers for the BBSHD soon, but...Eric is trying to support about ten full-time people. If he is not moving fast enough for you, feel free to pay cash up front for a higher performance controller, and make it available to customers now, instead of next year.

[madnut]

I wanted to note that my post was not intended for criticism rather for finding out information on availability of the controllers, like will they be available, when and also is luna working on higher voltage ones instead of high amperage one since that seems like it may work better with the bbshd.
I just finished my first build and already i know i want more power, i have a steep hill that has no shoulder so i have to either ride an extra mile to avoid it or ride up with traffic. With my bbshd @ 52V In the right gear if i do full throttle and peddle as had as i can at the same time i can go up around 24mph, this is ok since i can wait for an opening and get up the hill without creating too much congestion. But id love a system that can do 30 up the same hill. Cyclone seems like its just not as clean a build as i would like it to be. The assent seems like a cleaner option but both seem to be quite noisy. Hotrodded BBSHD with a built in controller seems like the best option, clean build powerful and quiet, I want it!

[Alan B]

Just to remind folks, motor current is the same, for a given torque, regardless of the battery voltage. Increasing the battery voltage doesn't make the motor or controller run cooler. Torque is proportional to motor current, and heat is proportional to motor current squared. Raising the battery voltage only decreases current in the battery and wiring to the controller. In the controller and downstream of the controller the current is determined by the motor windings and the torque you want it to produce. Battery voltage doesn't change currents there.

Since torque is going up with current and heat with the square of the current, things quickly get to meltdown.

Just so you know.

More torque would definitely be fun, however it will result in faster chain wear and more chain problems in general. If you really want to blast up hills you may want a different power transfer setup to the wheel.

You can of course wire up an external controller as others have done, right now.

[JPLabs]

That's probably the most clear, concise way I've seen someone explain motor current effects. Well done.

Alan, I'm sure you know this, but I wanted to mention it for the discussion: Higher voltage does allow higher motor speeds. The faster a motor spins, the more back EMF it generates - it works as a generator at the same time it's working as a motor, basically. So there is a motor voltage 'pushing back' against the battery, which increases with RPM. Battery voltage needs to be higher than back EMF to push current into the motor. So, higher battery voltage allows higher motor RPMs.

More RPMs means you can attack a hill in a lower gear. You get more wheel torque than at stock voltage, without increasing motor current/torque at all. Heat still goes up, but proportional to power (and RPM), instead of with square of power (and current). That's a more efficient way to utilize voltage increase for hill climbing, for those considering it.

EDIT: Oops, I see much of this was covered below, 2 days ago. Props to the guys who discussed, before I came along and didn't read the whole thread before commenting. I'll still leave the comment as it's a slightly different way of saying it.

[Alan B]

Thanks. Yes, you are correct, if you have a lower gear that runs out of speed then raising the voltage will allow using that gear. You will have to pedal much faster to keep up with the motor when using higher voltage, however. :)

[madnut]

As I understood from the high voltage setup post, the idea is that the higher voltage will allow the motor to spin faster, meaning delivering the same torque but at a higher speed. So then if before i put my bike in lowest gear the torque would be great the but speed would top out at around 20mph since the motor just cant spin any faster. But with 74V as i understood it can spin quite a bit faster while delivering the same high torque due to the low gear.

[Alan B]

The motor is presently spinning at some RPM and producing some torque, and if it is not accelerating or decelerating then this torque is exactly the amount needed to go at the speed you are going (in that gear). To spin faster it needs to generate more torque, and with that will come more heating. It cannot go faster at the torque level it is now.

Additional voltage will overcome the back EMF and allow forcing more current into the motor, and generating more heat.

The motor is not generating less heat due to higher voltage, but it might get to the top faster and integrate less heat into the core due to a reduction in transit time.

The question becomes, will it melt or crest first?

To go from 24 to 30 mph on your hill requires 25% more torque just for climbing, plus additional wind resistance. Just for the gradient 56% more heat will be generated, plus the additional for air resistance, so call it near 75% more heat will be generated.

Downshifting and using higher RPM in the motor with higher voltage will reduce the torque and reduce the current required as well as the heat. It will also make it impossible to pedal in a useful way (if it wasn't already). So using higher voltage and changing the gearing will help in generating more torque and less heat and less tension on the chain, but it isn't a pedaling friendly direction to go.

Note that as RPM increases other losses related to RPM will increase, and at some point they will contribute significant heating, depending on the motor construction.

[Rix Ryds]

Well, if Luna ain't gonna to sell 'em, guess I'll have to make my own!! DIY! I've got a BBSHD controller that lost the throttle input, (long story) I was thinking I would strip it and then see about shoe horning a Lyen 12fet sine wave controller into it. It will require making a new board, but since the stock controller uses 12 fets, I think it will all fit! Looks like that is what Luna did, that and add a big heat sink!

[Outsidediameter]

Just got a new Bbshd "bare", was hoping for a nice "suprise".No luck. Next year?

[spinningmagnets]

The stock BBSHD controller has 12 FETs, but...they are small. By moving to an external controller, you double the heat shedding. A 3077 12-FET at 45A and 60V should work very well (upgrade caps, easy and cheap) The phaserunner is pricy, but it would be an awesome match for BBSHD.

[Alan B]

I'm tempted to try the PhaseRunner. It is a sweet, smooth controller.

[Eric Luna]

Luna will be offering its own drive system soon capable of this kind of power for kit buyers..... more suitable than the BBSHD and at the same price range.

The BBSHD is not ours to mess with..... we need to worry about what happens if a lot of people burn up the bbshd and start criticizing bafang for unreliablity.

For sure the BBSHD is less reliable the more power you pump through it.... and when you add all the amps for users who dont get it ....they will fry it (climbing a big hill in high gear).

This is exactly what happened with the BBS02..... people overclocked it and it roasted the nylong gears a lot and the rumour got around that the bbs02 was unreliable. Very unfair for bafang.

The owner of bafang hates that his drives are being reprogrammed.


The bbshd already has a reputation of being unreliable and unsupported by dealers who are not capable of servicing it and dont understand it. Believe it or not its true outside of the luna arena. What happens when these other dealer customers figure out a way to buy our controller and fry their motor and try to send it back for support?

The BBSHD is bafangs product, and is a solid product...if luna had its own mid drive we would gladly offer the high performance to everyone (not just bike buyers) .... and that will soon happen.

Please dont take your expensive BBSHD's and plug home made external controllers to them..... you will just burn them out. We have been there and done that. (read bafang project x story)

We took a lot of time to ensure that our bbshd controller would maintain the integrity and the ruggedness of the regular drive system. Of course its less reliable and requires a better battery etc....but we feel better when we build the complete bike with rugged components quality chain etc.

Also honestly.... the bbshd is powerful enough at 30 amps.... at 50 amps you will need a better battery, a better driveline and only to get 20-30 percent more performance. (the boost in wattage does not provide incremental performance increase)

There are many who dont want to see 2500 watt bikes on our trails and streets and I feel where they are coming from.

We have had this controlller for 6 months...... we are trying to be responsible here.... i know we can sale the hell out of them....... Honestly i am not all about sellling or i would have released these in some rebranded bbshd kit.....

That being said....the good people who have been super loyal and supportive of us and people we trust ..... I am sending controllers out complimentary.....

This controller is special..... and my goal is not just to make money from this ...... i want to be a positive influence on the industry i believe highly in.

I could horror out the controllers....or i can keep them special..... something we give to loyal luna people.....and people who invest in helping us by buying one of our bikes at a crical stage when we are trying to build our company as a bike brand.

We are a new company.....and our controller is special...... we want to keep it special for a few people.....and not just people with money to buy our complete bike....but also people who have made significant contributions to this forum and have supported us from the beginning and have shown they are knowledgable and careufl and will use the controller with respect and not abuse it.

Trust me ..... the bbshd is awesome at 30 amps...... the 50 amps is a bit over the top....

I dont know ...... this is stupid.... but let me end with one of my favorite quotes:

With great power comes great responsibility - Spiderman's granpa

ERIC