Bafang Ultra Throttle Limiting

Hello everyone! I'm curious if anyone else has ran into this issue and / or has found a solution around it. The issue being that when the Bafang Ultra motors utilize a throttle; it seems that the throttle gives 100% regardless of the assist level. I am currently trying to get the motor to limit the throttle based on assist levels but have had zero luck. The update files Bafang sent me only limit the speed so the issue may be lost through translating the issue. I have also used the Besst and SZBAF programmers without luck. I have changed the throttle, speed and current % of the assist on SZBAF but get the same throttle input regardless of settings. Feel free to let me know if you have discovered a way to limit the throttle with the assist levels on the Ultra. Thank you for your time and help everyone!

i'd recommend checking hte voltage range the throttle actually outputs. it should range from around 0.8v or so when "off" up thru around 3.5-4.3v at most.

it should change gradually as you move the throttle thru it's movement range. if it jumps in voltage, or changes rapidly and then stays at max, then the throttle is either defective or badly designed.

(the magnets inside can come loose, and so can the sensor, and either one doing that can make the throttle respond differently than it should).

Amberwolf, thank you for your reply. The throttle settings from Bafang for this motor type is 1.5v start voltage and 3.6v end voltage. I think the issue is that the throttle acts like an on/off switch with these Ultra's; either 100% or nothing. We came to this theory based on schematics we got from Bafang years ago for a prototype Ultra; this prototype needed installation of a throttle and there was no plug, so we had to splice into the harness to access a certain signal wire. (which caused this 100% throttle when activated). Turns out Bafang wired their throttles in their production models the same exact way. Because of this I'm doubting that the issue is programed base. I'll talk to the engineers over at Bafang to confirm or deny this, with a reply to this thread.

QuietKat-Tech said:

Amberwolf, thank you for your reply. The throttle settings from Bafang for this motor type is 1.5v start voltage and 3.6v end voltage. I think the issue is that the throttle acts like an on/off switch with these Ultra's; either 100% or nothing. We came to this theory based on schematics we got from Bafang years ago for a prototype Ultra; this prototype needed installation of a throttle and there was no plug, so we had to splice into the harness to access a certain signal wire. (which caused this 100% throttle when activated). Turns out Bafang wired their throttles in their production models the same exact way. Because of this I'm doubting that the issue is programed base. I'll talk to the engineers over at Bafang to confirm or deny this, with a reply to this thread.

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while all of that is possible...you still need to verify your actual throttle on your actual bike is giving a variable voltage within the range the controller needs for operation, *and* that the voltage range aproximately matches the mechanical range of the throttle.

if the voltage range all happens in a tiny part of the mechanical range, it may well cause the controller to act as if it is on/off because the controllable area is so small you can't effectively move the throttle within it while riding.

if the throttle does give the correct voltage range over the correct mechanical range, then it's probably the way the controller responds to throttle; as you say it could be not even designed to do so.

(FIXED) We figured it out. The throttle limits could be adjusted slightly from the low input to high input but this didn't seem to solve the programming issue. We found in SZBAF software a setting for "Designated Assist". This was set at 9 instead of "by display command" we also adjusted the stock current % and speed % and after testing the throttle began function like the BBSHD would. A simple oversight that we didn't notice at first but now makes perfect sense. AmberWolf; again thank you for your help, as I have 2 units with the new updated control and one with a updated throttle. It seems that the ramp is much smoother now than the stock settings.

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I finialy figured it out all the testing and reprogramming I have been doing MOST only work in SPORT mode and Now I got it to work almost just like a BBSHD and NOW I am liking this bike even more it responds at the time I want it to and to how much pressure is set on the peddles and also enabled the throttle in pedal assist 0 ( PS: if you use pedal assists 0 ) then program it right in reality you have 6 pedal assists so all is good now. DPC 18 UART Display came with my bike
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Quietkat-Tech and zxhwk. Can you share your your configurations for the ultra controller that you have found that work the best. I am interested in settings that will give the best performance for climbing and not commuter top speed.

ejl6658- If you are using the Controllerst programming then attached are the settings Bafang / myself use.

The throttle function on the Ultra is similar to the BBSHD. I has what I would call "PAS priority", where the PAS level overrides the throttle input unless you give full throttle. If you use the throttle without pedaling, it works as you would expect. If you are pedaling and giving throttle at the same time, the throttle is sort of all-or-nothing.

This is real noticeable if you are in PAS 0 and using the throttle. Throttle works but as soon as you pedal with a little force, the motor stops. It goes full blast again after you stop pedaling. This can be pretty dangerous at times.

What I would prefer is if the throttle had priority over PAS, so once you hit the throttle, PAS is ignored. I think I will try doing the Darlington transistor mod like I did on my BBSHD to fix the problem.