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Overvolting BBS02

Cyclomania

10 kW
Joined
May 22, 2022
Messages
610
Location
Northern Europe
So I have been thinking about potentially overvolting the bbs02 with a new controller. Any idea how much it can take?

I was thinking like maybe using like a max current controller of 45a. But maybe this is way too much for it to handle? It might only be able to take like max current of 30 or something like that?

Also, any ideas what universal controllers might work with the bbs02 750watt 48vot motor? Kunteng or something like that.

I have opened it and I can clearly see hall sensors and phase. But I am not sure what this is in the picture. Is that perhaps throttle? Looks a bit weird since throttle wires usually have three wires. So not sure how to connect this one an to what. But phase wires there are three and hall the normal connection of five so those probably wont be a problem to connect.
 

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I think the connection in the picture is to the PAS.

Upfront: I'm no authority on any of this. To the max voltage for the motor core I'll guess 72 volts and current wise I'll stab 30 amps - and not for very long.

The BBS-FW firmware for the stock controller (which I use) does monitor core temps, and may be the easiest path to a little more reliable oomph from the little workpony BBS02 motor. I realize it can't accommodate running at a higher voltage than 52v.
 
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I think the connection in the picture is to the PAS.

Upfront: I'm no authority on any of this. To the max voltage for the motor core I'll guess 72 volts and current wise I'll stab 30 amps - and not for very long.

The BBS-FW firmware for the stock controller (which I use) does monitor core temps, and may be the easiest path to a little more reliable oomph from the little workpony BBS02 motor. I realize it can't accommodate running at a higher voltage than 52v.
Hmm good input. A 60 volt battery then, even with a stronger controller, might be a bad idea?

I was thinking maybe 52 volt battery and a controller of max 40. But that might be too much right? Better go with 52*30=1560 watts ?

Then I am overvolting it by about half.
 
[again, not an expert, and I'm regurgitating what I've gathered on these forums]

For the voltage, my take/question/concern would be, what components see what voltage levels. I believe that it's known that the BBS series controllers and the related displays aren't rated / won't survive much past 60 volts - in particular the capacitors. I've seen several write-ups on 72-volt Grin Phaserunner controller-driven BBS motor cores, which would lead me to believe whatever capacitors (and related wiring/circuitry) are in the core are rated for at least that much (logic and the 3-phase peak).

The BBS02, as with all of these motors, can only absorb/dissipate so much heat, and I picture full power needs like 1.) briefly riding fast to interact with car traffic while commuting versus 2.) slowly crawling up a steep hill on a hot day as two different heat dissipation problems. My CYC Photon and BBS02B motors can handle #1 very well but are not good at #2. For #1, I'm happy with ~2000 watts from my CYC and ~1500 watts from my BBS02 (set to 30amps via the open-source firmware). For the #2 long slog motor torture situations, I try to not ask for more than 600-700 watts, expecting and hoping that the motors can safely and reliably deal with it - with controller-monitoring thermal power cutback as insurance.

I also have two BBSHD motors with aftermarket controllers, capable of 2.5KW and 3KW each (battery limited). They too have thermal monitoring and seem to absorb the watts without any long-term issues. Likewise, on long slogs, I power back these motors too.

Short high-speed bursts/durations are helpful when trying to establish lane position while riding in cyclist-hating U.S. of A. When I trail/joy ride, I ride slower (for battery range conservation and to enjoy the sights).
 
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My BBS02 would sometimes get very toasty on 48V x 25A, and I always took pains to keep it geared low for high RPM and good efficiency.

I think if you want a hot rod mid drive, BBSHD is a better starting point. Better yet is Cyclone 3000W.

No matter which way you go, though, you're going to need an appetite for destroyed bike parts.
 
My BBS02 would sometimes get very toasty on 48V x 25A, and I always took pains to keep it geared low for high RPM and good efficiency.
Ah ok.

When you say geared low for high RPM, this essentially means putting in a pretty low gear when riding up for example a steep hill, correct?

The motor can probably handle higher wattage and voltages on flats right? But not as well during a steep hill climbing bike ride?

Any idea if there is something similar to statorade, which Ive seen people use for hub motors, but can work for mid drives like the bbs02? To cool it down during big power requirements.
 
[again, not an expert, and I'm regurgitating what I've gathered on these forums]

For the voltage, my take/question/concern would be, what components see what voltage levels. I believe that it's known that the BBS series controllers and the related displays aren't rated / won't survive much past 60 volts - in particular the capacitors. I've seen several write-ups on 72-volt Grin Phaserunner controller-driven BBS motor cores, which would lead me to believe whatever capacitors (and related wiring/circuitry) are in the core are rated for at least that much (logic and the 3-phase peak).

The BBS02, as with all of these motors, can only absorb/dissipate so much heat, and I picture full power needs like 1.) briefly riding fast to interact with car traffic while commuting versus 2.) slowly crawling up a steep hill on a hot day as two different heat dissipation problems. My CYC Photon and BBS02B motors can handle #1 very well, but are not good at #2. For #1 and/or like short duration needs, I'm happy with ~2000 watts from my CYC and ~1500 watts from my BBS02 (set to 30amps via the open-source firmware). For the #2 long slog motor torture situations, I try to not ask for more than 600-700 watts, expecting and hoping that the motors can safely and reliably deal with it - with controller-controlled thermal monitoring power cutback as insurance.

Short high-speed bursts/durations are helpful when trying to establish lane position while riding in cyclist-hating U.S. of A. When I trail/joy ride, I ride slower (for battery range conservation and to enjoy the sights).
Hmm ok. Yeah makes sense. But if I change both controller and display to something else, for example kt controller and display they might be able to handle it? But maybe not the motor as you said.
 
Ah ok.

When you say geared low for high RPM, this essentially means putting in a pretty low gear when riding up for example a steep hill, correct?

Yes, but it implies having enough gear range available to do that, and not having (or not using) gears that are too tall for the amount of power available. So for instance on my cargo bike with a 700c drive wheel, I used a 42T front sprocket with a custom 16-40 cassette stack. I fitted shorter 152mm cranks to make it easier to spin the pedals at the high end of the motor's range.

If, as many users do, you park the gears in the tallest ratio available and leave them there, even flat ground riding may not put the motor in its high efficiency range. Most BLDC motors need to run at least 80% as fast as their unloaded RPM to reach maximum efficiency. You don't have to get all the way there all the time, but if you don't cruise in the upper 1/3 of the motor speed range, you're sure to heat things up more than necessary.
 
Yes, but it implies having enough gear range available to do that, and not having (or not using) gears that are too tall for the amount of power available. So for instance on my cargo bike with a 700c drive wheel, I used a 42T front sprocket with a custom 16-40 cassette stack. I fitted shorter 152mm cranks to make it easier to spin the pedals at the high end of the motor's range.

If, as many users do, you park the gears in the tallest ratio available and leave them there, even flat ground riding may not put the motor in its high efficiency range. Most BLDC motors need to run at least 80% as fast as their unloaded RPM to reach maximum efficiency. You don't have to get all the way there all the time, but if you don't cruise in the upper 1/3 of the motor speed range, you're sure to heat things up more than necessary.
Aha so it is basically always a good thing to gear up gradually then? Because then the best efficiency is reached when I finally get to the highest level on a higher speed?
 
Aha so it is basically always a good thing to gear up gradually then? Because then the best efficiency is reached when I finally get to the highest level on a higher speed?
It's best and most efficient to start in a low gear, yes. (It also offers extra opportunities to thrash and abuse your gears if you don't have a shift cable power interrupter.) But in terms of heat soak, it's most important to use an efficient gear when you run for lengths of time at high load, like when cruising at top speed or climbing a long grade.
 
Hmm ok. Yeah makes sense. But if I change both controller and display to something else, for example kt controller and display they might be able to handle it? But maybe not the motor as you said.
The bbshd can handle 4000w for short term acceleration. Continuous at 4000 will fry the motor. I have one on EBay with a modded controller if you're interested. Firmware on the stock and modded controller upgraded to allow for customization.
 
Ah is a volume of a battery. Amps is something that is demanded from the battery. As a battery is rated in amps of demand and capacity in ah.
Maybe someone can define it in a different way. Of course.
 
Ah is a volume of a battery. Amps is something that is demanded from the battery. As a battery is rated in amps of demand and capacity in ah.
Maybe someone can define it in a different way. Of course.
Yes. I meant I am going for a KT controller for the BBS02. Externally. Haven't quite figured out how to get the cables out but I think through the same hole as the standard controller. Which probably means I wil lhave to keep the old controller in its place(?9 since it is providingf cover and is part of the motor's outer wall. But gut it.

But those BBS02 standard controllers only have max current of 25. I want to up it to 30, which is why I am going with the KT externally. Probably fastened to the down tube or something like that.
 
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So basically I want to do what the guy in this video does:

Only I want to up it to max current of 30a. And I also want to do it to the bbs02b.

I guess this could be done. But in the video I cannot quite see how he has dragged the new cables. I mean, the cables to the new controller should be going out of the BBS02b from the same opening. Which is on the pictures below.

Do you think he cuts out the old cables from the old controller and wire the new ones out of that same hole? I mean, I would have to keep the old shell of the older controller, right? Since the motor needs a cover on the outside there.
 

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So I just got this idea.

Remove old broken controller. Remove its guts and cut a square or rectangle between two of the three holes.

Push in the cable end fully or partly overlaping if needed for larger controller to get a good fit and screw in the three screws.

Done.

It would look like the version one or the first mid-drives with a kind of motor cylinder going down into a gearbox square kinda house at the bottom bracket area.
 
Hmm how do you mean with three screws in detail? Screw inside the rectangle there kind of?
The three screw points, the screws that you have on the motor which the controller that is to be gutted is usually placed.

(Bafang original controller is little more than an inch thick and small controllers are about an inch thick? capiche? So for time saving sake this might be a good way to "really" integrate a new controller into the motor, hehe )

In my head it looks neat and tidy a bit but maybe reality is more like a Frankenstein creation
 
I did use a small controller once but it was a bit jerky. It's been a long time since and it worked. The way I did it back then was cut a hole in the Bafang original controller and leading the cables from the new controller there. Back then I only connected the three thick phase wires. Maybe one can make it work more flawlessly by implementing the original PAS somehow. I want to try sometime in the future again.
 
I did use a small controller once but it was a bit jerky. It's been a long time since and it worked. The way I did it back then was cut a hole in the Bafang original controller and leading the cables from the new controller there. Back then I only connected the three thick phase wires.
Did you cut the hole in the spot where the original cables comes out?
If there became some extra space there, because of the hole, how did you waterproof it? Use some silicone or something?

Do you have a pic of the whole thing? Would be interesting to see how you did it.

The way I am probably going to approach this is to make a hole where the old cables went out in some way. Not sure how I am going to waterproof the area though. I dont need water inside my motor. Only a strong motor :)
 
Did you cut the hole in the spot where the original cables comes out?
If there became some extra space there, because of the hole, how did you waterproof it? Use some silicone or something?

Do you have a pic of the whole thing? Would be interesting to see how you did it.

The way I am probably going to approach this is to make a hole where the old cables went out in some way. Not sure how I am going to waterproof the area though. I dont need water inside my motor. Only a strong motor :)
I'm sorry I don't have a photo. It'ss something I did and because it's not that advanced as you just use the original hole and put the controller without electronic parts and filling back so the look will be keept. The water protection you can just ignore or add silicon in the opening / original cable area. Also you could keep the small rubber part and re-use it with your new wires.

So the new controller can be part of the old. Means a lot of work or just outside. The funny idea was that it could be half-integrated to the old controller if the new one was in the size of about 9 by 5 by 3 centimeters.
 
I have been running the bbs02b at 48v 33 amps (1584w) for 2 months without any problems. Using the open source firmware.
 
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