Project Beetah (Bagi B10 Bold Plus + Revi Cheetah) Top speed too low (?)

Joined
Apr 5, 2022
Messages
3
I am working on transferring all of the electrical system from a 2021 Revi Cheetah to my existing Bagi B10 Bold Plus. I am using the Cheetah's motor, battery, display, controller, and PAS (everything but the throttle and light system). Everything works great EXCEPT I can not get more than 22-23 MPH with throttle or PAS. The display has been set to register the 20" fat tire wheel vs the original 26" fat tire and top speed is set to the highest (99). I realize that I might lose a bit of top speed going from the large wheel to the small diameter - but 5 MPH seems a bit much. The speeds have been tested with Strava to use GPS vs relying on the display's speedometer. I have also tried the Eggrider V2 display to adjust the Lishui controller settings too but in the app it's only saying the max speed is 41 km/h (around 25 mph) but this is the same setup on the Cheetah that can easily do 45 kmh / 28 mph. Is there any work around to this or do I need to do a new controller to get past 23 here?

Thanks for your time and hopefully your assistance!

Parts list:
Motor: Bafang G060 750W (07 variant)
Controller: Lishui LSW1332-47F
Battery: 48V 17.5Ah
Display: Revi Cheetah color display (Not 100% sure but think it is a version of the KD986)
 
es0tericcha0s said:
Everything works great EXCEPT I can not get more than 22-23 MPH with throttle or PAS. The display has been set to register the 20" fat tire wheel vs the original 26" fat tire and top speed is set to the highest (99). I realize that I might lose a bit of top speed going from the large wheel to the small diameter - but 5 MPH seems a bit much.
<snip>
the app it's only saying the max speed is 41 km/h (around 25 mph) but this is the same setup on the Cheetah that can easily do 45 kmh / 28 mph.

20" / 26" = 0.77
22mph / 28mph = 0.79

Those ratios are close enough to say that it is pretty likely simply that your smaller wheel vs the winding of the motor vs the voltage of your system is just not able to spin any faster under the load you have.

You can test the system with the wheel offground to see if it is a controller limitation (speed limiting); if it is the max wheel speed will be exactly the same as it was while riding. It may require a new controller and matching display to correct this, but it may also not result in much (any) more speed.

The most likely result is that it will be a little (few percent) faster offground. In that case, it's not controller-speed-limited, and is just too low a voltage. You'd need to either change the motor for one with a faster winding, or the battery for a higher voltage and the controller and display for a set compatible with that.

While this scenario is not very likely, if it's a lot faster offground, then it could be not enough current to drive it at the faster speed under load. That probably requires a new controller and matching display that can supply enough current to drive the system. If the battery cant' supply that current (without sagging in voltage more), it would also need a new battery (or a second one in parallel).
 
@amberwolf - Thank you! That was very helpful. I just expected a bit more because the original configuration of a cheaper controller (22a max set to 20a), 500W Bafang motor, and 48V 14Ah battery could do 25-26. Also, this same motor I've seen on other fat tire folding bikes with a 25a controller do 25-28. It is what it is and I do prefer the overall acceleration the bike now has so I'll keep it like this and just set up my dual battery next.
 
That's one of the naturally slowest things you could loosely characterize as a bike. There's an efficiency penalty associated with it.

You never saw a bike anything like that until after there was motor power for it.
 
Chalo said:
That's one of the naturally slowest things you could loosely characterize as a bike. There's an efficiency penalty associated with it.

You never saw a bike anything like that until after there was motor power for it.

Agreed and I'm about 6'3 so look ridiculous on it and definitely can't get a full extension but I certainly didn't get it to look cool or to pedal too hard :D I've got an ebike with a torque sensor or an acoustic bike when I want to pedal more. Was just wondering why I've added a more powerful motor and controller yet lost top speed.
 
Totally worth it to monkey around with the Grin Tech hub motor simulator, changing things like wheel size and battery voltage, until these discrepancies make more sense to you.

https://ebikes.ca/tools/simulator.html
 
"You never saw a bike anything like that until after there was motor power for it."

The Schwinn "Krate" dragster inspired bikes of the sixties were way worse pedal bikes than those Cheetas (and rather similar in profile) No bike motors back then. Same with the Orange County choppers, and, you could argue, the balloon tire cruisers of the "prewar classic" era..."tanks", fender skirts, swoopy frames...

Maximum efficiency under pedal power is only one of many factors in deciding whether a bike is "good"...not even the most important one, in many cases. If it were, we'd all be pedaling recumbents with full streamlined bodies.

The full fat tires on street bikes are pretty stupid, though.
 
classicalgas said:
"You never saw a bike anything like that until after there was motor power for it."

The Schwinn "Krate" dragster inspired bikes of the sixties were way worse pedal bikes than those Cheetas (and rather similar in profile) No bike motors back then. Same with the Orange County choppers, and, you could argue, the balloon tire cruisers of the "prewar classic" era..."tanks", fender skirts, swoopy frames...

I was talking about fat tire, small wheel bikes like the Bagi B10, not the Revi Cheetah. The Revi looks a little impaired by its fashion tires, but otherwise workable.

Balloon tire cruisers are actually very efficient bikes for their intended speed (slow) and rider effort level (low). The biggest problem I see with them is their riders tend to place the saddle too low and thereby hobble their pedaling somewhat. In the big picture, I think most people would be better served by a traditional cruiser bike than by whatever other kind of bike they chose.

Drop bar bikes, suspension bikes, BMX bikes, and for cripes' sake fatbikes, all are bought vastly in excess of their usefulness to the buyers. Hybrids and cruisers often get passed over, but would be a better choice for most folks.
 
Back
Top