Luna BBSHD Ludicrous V2 controller documentation

[xcnick]

I am not getting the speedometer to work correctly. It asks for the diameter of the wheel, but the speed reads faster than it really is. Could VESC be asking for the radius?

[xcnick]

The manual talks about being able to use taller gears. How does 72 volt vs. 52 volt effect this matrix. My tests find the 72 volt can work with a slightly taller gear than 52.

[xcnick]

stupid is as stupid does, can't wait to try it.

[marcos]

Ah, no harm if its set to 6500rpm. In fact 6500rpm should be the default in the ludicrous profile.

[xcnick]

the slider in vesc. It is at 5000, but it will slide up to 6500

[marcos]

I had no intention on limiting the max speed so either the max rpm is 5000 or I mistyped that number in the app code. Will take look

[xcnick]

What is the risk of moving from the default 5000 max RPM to 6000 or 6500?

Interesting graph, I need to look again the id from my rides.

[AZguy]

FYI if you don't already have these numbers - the primary reduction ratio is 9:32 and the secondary 11:68 for an overall reduction 99:2176 =~ 1:22

6500rpm = chain ring speed of ~296rpm (ripping)

3000rpm is ~136rpm... If I remember right (not so sure about that!) top ring speed on V1 is somewhere around 180rpm with fresh 52V which is just shy of 4000rpm at motor... more typically I see top ring speed on V1 of about 160rpm (I think) with 48V not all fresh for 3500rpm

[marcos]

RPM is limited to 6500rpm, field weakening start is dynamic, depends on the input voltage. If you are running at low voltage (or battery is sagging a lot) FW will start much earlier. In the logs you cab see exactly when FW happens by checking the id current.

Efficiency is best in mid-high rpm and low torque, and tanks at full throttle.

Conceptually it would look something like this (redder is more efficiency)



So basically, if you are after efficiency reduce the torque (phase Amps), its the most effective approach.

[xcnick]

RPM questions. What RPM does the V1 stop at? What RPM is the start of field weakening? I am guessing 3000. When I use a transmission I am thinking the most efficient acceleration is to shift at 3000 RPM and then go to 5000 RPM when in high gear and you need to go fifty miles and hour. I wish the display showed RPM.

[xcnick]

Peddles work fine. It is hard to notice with a chain guard. I went on line to see if there exist a fixie hub in 120mm. Nope.

[AZguy]

That makes sense - the freewheel in the hubs just aren't built for that kind of torque

JB weld has many uses =]

I'm guessing you removed the pedals and crank arms - put some pegs on the beast?

I doubt the shaft is the problem, the forces are highest on the rollers and ramps and if worn or damaged I'd be betting on the ramps... but you never know and like I said the lubrication is really important

[AZguy]

All makes sense - appreciate the explanation

[xcnick]

Interesting. The diameter of the shaft must be critical to make this work. It could be a worn shaft, not a bad clutch. Speaking of clutches, I always break the clutch in the bicycle wheel hub. After a couple of sprag replacements the whole thing is useless. I have just poured JB weld, 9,000 into the whole thing to lock it up. It is now a fixie. Coasting, the chain spins like on a motorcycle. I am thinking this clutch we are talking about in the HD it is about to get a work out. The test is on a HD with a V1 Ludi controller. Single speed, I don't know if this would work with a derailleur. But I have high hopes this fixes the weakest part of my snow bike concept.

[xcnick]

"It really comes to life." Is that a technical term? LOL, but that is the best way to describe it. It is most apparent when I go back to 52. I keep looking down at the motor as if there is something wrong.