Low end torque weak on Stealth Bomber clone bike

[AGS]

I think I have worked out what’s wrong. It looks like the OP has been keeping pas on level 1 all of the time which keeps the bike in eco mode. Raising the pas levels changes it from eco to normal to boost on the SW900 display.

If it was my bike I would disable pas completely on P10 and run it in throttle mode only.

 

[E-HP]

I think I have worked out what’s wrong. It looks like the OP has been keeping pas on level 1 all of the time which keeps the bike in eco mode. Raising the pas levels changes it from eco to normal to boost on the SW900 display.

That would be ironic, 2 threads and 47 posts later . Hopefully that solves it.

 

[ebikeFan1234]

I did a brief test this morning - dialed PAS to level 5 which changed mode from ECO to Sport. In another test, I turned off PAS completely and mode was Sport. In both the tests, I didn't feel a noticeable difference from standstill with full throttle. The bike did feel a bit quicker than ECO mode. I need to spend more time doing the tests, will report back 0-30 and 1/8 mile times.

 

[neptronix]

I got 5 on it's the controller programming.

 

[AGS]

I got 5 on it's the controller programming.

Yep me too.

 

[ebikeFan1234]

Here’s the 0-30 mph and 1/8 mile run for Eco = pas1 and Power = pas5 modes. 2 tests each. Pas5 is slightly faster and that may be within the margin of test error. All runs felt very similar to me.

I also found an online SB vendor who sells high powered like 12kw variants for both top speed and strong start, they build on 2.5T motor. I am thinking I don’t need to change my motor either. Just need to find the right balance of controller config or a better controller. Hoping I don’t need to change battery

 

[AGS]

You need to either learn how to configure your controller or find someone capable of configuring it for you.

You have a 14hp ebike that is currently performing as a 1/4 hp e-bike. One of my bikes has a 250 watt motor and it is faster than your bike.

If you just go swapping parts you will still be in the same situation or even worse, the bike won’t run at all.

Did the person who assembled the bike give you the Bluetooth or pc cable?

 

[E-HP]

I think you need more phase amps, with this motor, or even with a 3..5T, but you haven’t confirmed that you have your phase amps maxxed out already, so I’ll ask the obvious question. Do you even know how to access those parameters and change them? Can you please provide screen shots of all of your controller settings (not the display)?

 

[ebikeFan1234]

I haven't done a single change on the bike other than tweak settings on the SW900 display. Once I tried to open the side panel to access the battery and such, the screws came off. But the panel won't open as there was some kind of adhesive on its edges for a tight/rattle free experience. I didn't feel comfortable to brute force it.

The bike is going to a mechanic shortly to work on other things like new brakes.
They don't know much about the electrical stuff on the bike
I am going to take their help to open the bike and take close up pics of battery and controller. Also I will learn how to do it myself.

Then at a later point, I will try to get into the controller settings. assuming its Saboton (I don't have Bluetooth dongle), I am hoping I can use a standard USB cable to connect to Windows PC. And then I can post the settings here.

I am comfortable with science and physics of these bikes and have learnt a lot about BLDC recently. I am very motivated to tune this bike, hoping I can gain some new "handyman" skills needed in the journey.

 

[dominik h]

Standard USB won't work with the Sabvoton.

 

[E-HP]

I haven't done a single change on the bike other than tweak settings on the SW900 display.

Well glad I asked. You had the opportunity to provide that clarification at around post #3, coincidentally in both of your threads, when folks started mentioning the program settings and phase amp limits. You even asked about parameters in the MQCon app in the other thread, which seemed to imply that you had used it.

You may just need to search for a shop that can tune your controller and upgrade the bike to your specs. That way they can see for themselves whats going on without guessing.

 

[neptronix]

I am comfortable with science and physics of these bikes and have learnt a lot about BLDC recently. I am very motivated to tune this bike, hoping I can gain some new "handyman" skills needed in the journey.

Sounds like you have the right attitude to take advantage of ES!

 

[ebikeFan1234]

Feel free to chime in on a related thread

My ideal bike - combo of Stealth Bomber and Talaria Sting R

I have owned both Stealth Bomber (clone) and Talaria MX4 Sting R. Based on that I have a vision for an "ideal" bike for my needs. First a quick summary of my requirements I ride 98% on roads and a bit of off-road like grass in a park, light gravel. I want the bike to be sturdy so it can take...

endless-sphere.com

 

[bengxe]

The Sabvoton cable is expensive, but you can use a usb-serial converter with a 2nd usb-a end added. That will allow you to connect to a pc, but given how much trouble you seem to have accessing the controller you may want to just buy the bluetooth dongle. The windows software does give you a little more control, but the important stuff is all in the app.

 

[AGS]

All of this assumes that you have a Sabvoton controller and you won’t know that until the covers are removed.

The covers are probably stuck because the weather sealing tape is sticky on the wrong side. I have had this problem, so now I smear Vaseline on mine now to stop them sticking. You may find the weather sealing tape needs to be replaced when you prise the covers off.

Also, the assembler may have put the Bluetooth adaptor inside the covers for safe keeping.

So you really need to get those covers off and verify what controller you have and also confirm whether or not you have the appropriate adaptors to access the configuration app.

 

[ebikeFan1234]

Here are the pics of my bike's internals. It seems I do have 72v, 45 ah battery. And Saboton 72v 150A controller.

Based on this, can we infer BMS max current?

Perhaps the controller isn't configured for performance. See the other cables. Bluetooth dongle isn't there. Do advise what cable I need to connect to Windows PC, where to buy it from?

These pics are straight from the mechanic. If other pics are needed, please describe and I can have the mechanic take action.

thanks for all your input!

Looking forward to tuning this bike for performance, My requirements in short max acceleration/torque and top end speed of 55 mph. We can tradeoff further top speed to optimize 0-55 range

 

[bengxe]

The cheap option is to take one of these and add another usb a cable end. The sabvoton cable and bluetooth dongle are both expensive and easy to google.
We can't tell you anything more about your battery from this even if we assume those numbers mean what you say. You may want to open the shrink wrap to see what kind of cells you have at least, you may find a sticker on the BMS board, assuming it has one.

 

[dominik h]

Set phase amps to the max value (350A) , this gives you more starting tourque. Battery current can be set to whatever you think your battery and BMS can handle.

 

[bengxe]

9600w at 140A would imply a very saggy or discharged battery, it really should only be pulling ~120A at that wattage on a 72v battery. Does the sw900 not show you battery voltage? If you haven't, you may want to check for a bluetooth connection from inside that battery.

 

[E-HP]

Yep me too.

The seller may have programmed it “correctly” to not kill the battery.

 

[neptronix]

yes, more phase amps = more low end torque, they should be somewhere between a 2:1 to 3:1 ratio of phase amps to battery amps

 

[ebikeFan1234]

Closing the thread here. Finally got the opportunity to use MQCon app. The stock settings were pretty much extracting all the performance they could from the 2.5T motor. Phase current was already set to max of 350A.

Tweaked few other things like changed Acceleration (ms) from 200 to 10. Bumped Mid-throttle current from 175 to 250A. Set the bike for "hard start".

The net result is a marginal change in responsiveness of the bike. For context, battery is 72 x 45 ah, BMS = 150A, Controller is Sabvoton 72140, Motor is QS 273 2.5T.

The guy who helped me owns a SB bike with 4T motor, and said his can wheelie easily.

Thank you to the forum for all the suggestions so far!! I have learnt a lot during this exercise.

 

[ebikeFan1234]

Per this video, and the comment (2.5t motor = 177ft/lbs and 5t motor = 222ft/lbs of torque)

That's a 25% difference. Wondering if that makes a substantial difference where 2.5T can't wheelie at all, and 5T wheelies at will..
I was hoping 5T has 200% torque of 2.5T based on their turn counts.

Do share your perspectives, thank you!

 

[neptronix]

You're on the right track, however, one consequence is that you'll have half the speed.. Does that work for you?

 

[ebikeFan1234]

The 5T top speed is a bit much of tradeoff than what I want. 4T might be better. But first I want to understand whether it's just 25% torque difference between 2.T and 5T. Thats sounds little to make such a dramatic difference in the feel of the bike

if that's the case, then swapping the controller from Sabvoton 72150 to 72200 (33% difference in current), can achieve similar effect. and a much cheaper and faster delivery time option too