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I tested the max speed on my Gotway acm 16


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On 10/1/2016 at 11:04 AM, Tishawn Fahie said:

just got my ACM maybe 2 days ago.... I think I'm going to try a similar speed test. The difference being the 12 Mostfet version. Just gotta find a nice flat straight away.. And purchase some IRON Man armor! Because I'm still confused - He had tilt back set on 45km but he had the option to set it to 48km..... which leaves me to believe theres wiggle room for more power.. I believe it's the 6 mosfet board is why is why it cut out on you....

Again thank you for your bravery!

@Tishawn Fahie, I don't recommend you testing the fastest speed. You will wreck a brand new ACM and possibly could get hurt as well. 12mosfet is used for better surge safety esp. when jumping off of curbs, etc. More mosfets help to spread the heat. This is what I've been told. Makes sense based on the info I found on mosfet burning out due to heat.

12 mosfets shouldn't increase the max speed!! Like I said before, do a lift test first. Most ACM's will do 50-52kmh. Minus 10kmh from your max lift speed, you should stay under that speed for safety. Gives you the rider some cushion from a potential HS cutout. This method hasn't failed me yet. 

Plus like how @John Eucist was saying, when the tilt back is set, I believe it does need more current to adjust the wheel to tilt back while holding the speed. GotWay should not even allow a tilt back at these speeds for this very reason. If you are going to ride close to max speeds, disable the tilt back. Can't prove this however, but if anyone has an electronics background, i would think you could easily see how the board would need more current to adjust the wheel in tilt back at a certain speed.

 

 

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On 10/1/2016 at 11:24 AM, John Eucist said:

It's possible that max speed power cutouts (unlike lack of torque) are not weight dependent.  Although I'm not certain.  Perhaps others can chime in on this.

On a really powerfull motor it will not be weight dependent since this should never happen the tilt back will kick in much before the cutout, on a weak motor it is weight dependant since the motor no longer has the power to balance and the cutout occurs before the tilt back which is what happens in the last part of the video and the rider only weight 65kg, the cutout would happen much sooner with a 120kg rider since it takes more power to balance a hevier person, and if it is a tall heavy person much more power it is needed, also at that speed the wind resistance begins to play a role.

By strong/weak motor I mean the combination motor and battery pack.

Be safe buy wheels with lots of torque and power, and avoid the max speed.

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On 1.10.2016 at 9:00 PM, John Eucist said:

 

@esaj do you know the theoretical answer to this?  Or could you tag someone that you think might know? :) 

 

On 1.10.2016 at 9:24 PM, John Eucist said:

It's possible that max speed power cutouts (unlike lack of torque) are not weight dependent.  Although I'm not certain.  Perhaps others can chime in on this.

Sorry, missed this earlier... to my knowledge, it's just like @NevNutz said above, 12 mosfets will mostly just help with handling larger currents, once the motor back-EMF reaches the battery voltage (or a little under, I don't think the PWM can be pushed to 100% duty cycle, as the "pumping" of voltage for the gate needs the voltage to go up and down?) the motor cannot run any faster, even if the batteries were capable of producing more power. To create a current, which in case of an electric motor translates into torque, you need a voltage difference. If both the "input" (battery/PWM cycle max voltage) and the motor generated voltage (back-EMF) are the same, no current will flow, and thus no torque either... at best, the motor can keep running at max speed, but if you keep leaning forwards, it cannot pull you back upright and will start to fall forwards. Adding more mosfets won't help with this.

But, it's hard to say whether the fall in the video was because the motor couldn't spin any faster or if it ran out of torque (which are partially related, see the point about voltages above). Also the wheel trying to tilt-back at high speed could overload the system for a brief moment, and for example the BMS overcurrent or undervoltage protection might trigger, shutting down the wheel.

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8 hours ago, NevNutz said:

@Tishawn Fahie, I don't recommend you testing the fastest speed. You will wreck a brand new ACM and possibly could get hurt as well. 12mosfet is used for better surge safety esp. when jumping off of curbs, etc. More mosfets help to spread the heat. This is what I've been told. Makes sense based on the info I found on mosfet burning out due to heat.

12 mosfets shouldn't increase the max speed!! Like I said before, do a lift test first. Most ACM's will do 50-52kmh. Minus 10kmh from your max lift speed, you should stay under that speed for safety. Gives you the rider some cushion from a potential HS cutout. This method hasn't failed me yet. 

Plus like how @John Eucist was saying, when the tilt back is set, I believe it does need more current to adjust the wheel to tilt back while holding the speed. GotWay should not even allow a tilt back at these speeds for this very reason. If you are going to ride close to max speeds, disable the tilt back. Can't prove this however, but if anyone has an electronics background, i would think you could easily see how the board would need more current to adjust the wheel in tilt back at a certain speed.

 

 

Good call - For the first time I rode in to work this morning (approximately 15 miles) - The speed is good enough for me. I would even say Perfect... There's no reason for me to attempt anywhere near 27mph....

 

@NevNutz Thank you for clarifying - I'm no electronics expert by no means. I did purchase a Garmin action cam(ultra 30) to check some speeds as I ride... I still find it weird that there's an option to select 48km titlback...thats why i thought it was a mostfet limitation.

 

 

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7 hours ago, EU GUY said:

Did you get the 80% power (or any other) alarm before the cut off ?

"Yes. The warning started at 35kmh"

I would suggest, an appropriate claim from the manufacturer , keeping the safety of the buyer in mind,  would state "a safe top speed on level ground for this device, with a 65kg rider is 35kph. Any higher speed should not be attempted."

There is no justification to have 48kph as an optional tilt back on this model.

Its not only gotway who are making false claims of performance, this is only an example of widespread deceptive claims being made by euc companies 

Things need to change before someone is seriously injured unnecessarily,  or worse  

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18 hours ago, Mistagear said:

I would suggest, an appropriate claim from the manufacturer , keeping the safety of the buyer in mind,  would state "a safe top speed on level ground for this device, with a 65kg rider is 35kph. Any higher speed should not be attempted."

There is no justification to have 48kph as an optional tilt back on this model.

Its not only gotway who are making false claims of performance, this is only an example of widespread deceptive claims being made by euc companies 

Things need to change before someone is seriously injured unnecessarily,  or worse  

Funny thing is that now, after i did the speedtest.. i usually ride at 20-25 kmh and think it's fast enough. At least something good came from it :)

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