Please weigh in: BBS02 750 with 12S 30A RC Controller?

mwkeefer

mwkeefer

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Jun 14, 2009
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Location
Malvern, PA USA
Hello all,

Before going and doing something I'm sure to regret, I thought I should ask opinions here.

I have located in an old drawer an RC controller with good heatsink and programmable delays and power levels and cutouts and such.

I'm considering disconnecting the Lyen 6 FET sensored controller, leaving the loging system in place and seeing if there is a difference in heat / performance, etc.

Not even sure this will work but I doubt an additional 5A at 44.4v nominal should affect it - the power output is the same as 25A at 48v nominal isn't it?

What do you think before I toast a controller outright or worse a BBS02?

This would in theory with the right controller side cover allow us to embed RC style sensorless controllers right in the existing motor eliminating the needs for Bafang Controllers and opening up a very wide world of options to us.

-Mike
 
It is claimed on here that the motor can handle 1250 W (50 V * 25 A) for several minutes without overheating, so 1330 W (44.4 V * 30 A) probably wouldn't be too stressful. I assume you're talking about LiPo, in which case the voltage is significantly higher than nominal early in the discharge, so keep that in mind.

Since the controller has programmable power levels, why not set a level you're comfortable with and then bump it up from there until you can feel the motor getting warm?
 
cycborg said:
It is claimed on here that the motor can handle 1250 W (50 V * 25 A) for several minutes without overheating, so 1330 W (44.4 V * 30 A) probably wouldn't be too stressful. I assume you're talking about LiPo, in which case the voltage is significantly higher than nominal early in the discharge, so keep that in mind.

Since the controller has programmable power levels, why not set a level you're comfortable with and then bump it up from there until you can feel the motor getting warm?
Click to expand...

I've already been running 15S in stock 25-26A controller for months nominal at 55.5 with zero issues (none I ddint cause myself)

-mike
 
Sounds like power isn't a problem, and it's probably a good match since the motor probably looks a lot like a medium-sized RC motor, as far as the controller is concerned - 8 pole pairs, something like 55 Kv.
 
Well, consensus in... I'm gonna try it with a little 30A RC controller I have already beefed up the caps with LowESR type and added forced air cooling for when the bike isn't in motion. Using several RC controllers for various builds, I find heat really becomes an issue when you push the controller normally and it has airflow but then you stop and it basically cooks.... I'm hoping this may be a viable solution for some with BBS02 issues, quite small enough to solve the issue... 6 FET Infineon works well enough (great in fact) but it's so BIG.

In reality if this works, I'm going to research building my own sensorless BLDC using some surface mount equivalent of IRFB3077 or better if the thermal dissipation will suffice (need to calculate it) if not I'll design around a bank of 6 TO-220 style 3077 but minaturize the rest as much as possible (if I can't find a controller which suits this already).

I had wanted to use the Castle Creations ICE 2 line but it's discontinued and the lowest power controller they offer which supports 50v is 40A - that being about 10A lower than transient peaks so figure 50A peaks for 2500w... smoke that BBS02 up, sad really I love Castle Creations Controllers.

If anyone has suggestions for alternative controllers to test, maybe something with better current limiting (or limiting at all) so I can dial them in to be a perfect fit for BBS02 style drives? I'm all ears :)

-Mike
 
mwkeefer said:
Well, consensus in... I'm gonna try it with a little 30A RC controller I have already beefed up the caps with LowESR type and added forced air cooling for when the bike isn't in motion. Using several RC controllers for various builds, I find heat really becomes an issue when you push the controller normally and it has airflow but then you stop and it basically cooks.... I'm hoping this may be a viable solution for some with BBS02 issues, quite small enough to solve the issue... 6 FET Infineon works well enough (great in fact) but it's so BIG.

In reality if this works, I'm going to research building my own sensorless BLDC using some surface mount equivalent of IRFB3077 or better if the thermal dissipation will suffice (need to calculate it) if not I'll design around a bank of 6 TO-220 style 3077 but minaturize the rest as much as possible (if I can't find a controller which suits this already).

I had wanted to use the Castle Creations ICE 2 line but it's discontinued and the lowest power controller they offer which supports 50v is 40A - that being about 10A lower than transient peaks so figure 50A peaks for 2500w... smoke that BBS02 up, sad really I love Castle Creations Controllers.

If anyone has suggestions for alternative controllers to test, maybe something with better current limiting (or limiting at all) so I can dial them in to be a perfect fit for BBS02 style drives? I'm all ears :)

-Mike
Click to expand...

I can't help with the design but I would like to encourage you to try. I would love to swap out the original with something that had more control.
I think my chain, derailleur and gears are pretty much maxed out with the 9 fet anyway. Creating a smoother more reliable controller would be sweet. I have gotten to like the pas system but the throttle response kinda sucks.
 
You might want to check out this thread:
http://endless-sphere.com/forums/viewtopic.php?f=35&t=63540
It is an open source ESC that has some potential for ebikes as it is going to be higher voltage. I started another thread awhile back about RC controllers for bikes- probably buried. There was another poster on that thread that was trying to design something similar. Coming to ebikes from eboards made me frustrated at the size of bike controllers, hence the post trying to understand the design differences. You get high amps and low voltage with the RC stuff and low amps, high volts with ebike. However the size difference is huge. The BBS02 is actually one of the smallest ebike controllers out there, at least that I know. I would love to be able to just zip tie an ebike controller to the frame. Someday!
Recumpence is another that uses RC stuff - but mostly high end like the Castle HV.
Good luck.
 
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