King Song "800W" vs Gotway "1500W" - Is it on the "same scale"?

[John Eucist]

So the Gotway ACM supposedly has a "1500W" motor while the King Song KS16 supposedly has a "800W" motor.  Is the ACM really almost double the motor wattage of the KS16?  Is there any way that we can actually verify this or do we just take the word from the manufacturers' specs?

[HEC]

28 minutes ago, John Eucist said:

So the Gotway ACM supposedly has a "1500W" motor while the King Song KS16 supposedly has a "800W" motor.  Is the ACM really almost double the motor wattage of the KS16?  Is there any way that we can actually verify this or do we just take the word from the manufacturers' specs?

The problem is that different manufacturers are quoting different type of specs to confuse customers and to look better. King Song is specifying sustained motor power while Gotway is " cheating" using the peak / max value instead. It's the same like producers of cheap audio electronic quoting the speaker W outputs in peak value and on top of it adding it together for all speakers

[TremF]

49 minutes ago, HEC said:

King Song is specifying sustained motor power while Gotway is " cheating" using the peak / max value instead. 

Erm no?... taken from the official spec of the ACM...

"Motor Power 1500W (peak around 3000W)"

[HEC]

1 hour ago, TremF said:

Erm no?... taken from the official spec of the ACM...

"Motor Power 1500W (peak around 3000W)"

Then I stand corrected. Though there is one more spec which should accompany the motor ratings and that's torque as even high power motor is not direct guarantee of high torque (or speed). It also seems a bit strange having sustained power 1500 and max 3000 - usually the max is 3 or 3.5 time more than sustained. Could be down to different torques.

[TremF]

Agreed. It would be useful to know the torque but the best we have is -

"Uphill 25°Tested by a 100kg person(If less than 100kg,will be higher degree)"

Your theory on the peak being linked to torque could be right. Maybe the ACM torque isn't as much as an EUC with a 800w motor and the same 3000w peak BUT my ACM definitely accelerates up and climbs one of my hills a lot faster than my Ninebot One E+ can.

 

EDIT: I've just read the spec of my E+ and it appears the rated is 500w and the max is 1500w so no wonder the ACM is quicker.

[HEC]

@TremF And there is also question of "efficiency" of the motor as two different motors with the same torque and sustained consumption of let's say 500W might not produce the same force be it due to the different quality of windings, bearings or some other mechanical differences. We really need some unified method of comparing all the quoted EUC stats as they're currently all over the place - battery capacity, motor power (sustained vs maxed), speed, range and torque. Most of them depending on the weight (and height) of the raider, weather conditions (temperature, wind speed) and so on. It's jungle out there!

[Chriull]

3 hours ago, John Eucist said:

So the Gotway ACM supposedly has a "1500W" motor while the King Song KS16 supposedly has a "800W" motor.  Is the ACM really almost double the motor wattage of the KS16?  Is there any way that we can actually verify this or do we just take the word from the manufacturers' specs?

 

2 hours ago, TremF said:

Erm no?... taken from the official spec of the ACM...

"Motor Power 1500W (peak around 3000W)"

I'd say that for us users the available power brought "from the wheel to the road" is the most important number.

And for this we'd have the peak power (with overheating) and the sustained power (temperature of the wheel settles in a "tolerable" range).

Since most of us do not have a dynamometer the only way for us users to verify this numbers is to search a quite constant long enough incline in the neighbourhood. And then measure the max reachable speed possible at this incline. And this with and without overheating (so best at a "defined" ambient temperature).

With the powers for the air drag ( Pad=0,5 * cw (~0,78) * roh (~1,25) * A (~1 m²) * v²) rolling resistance ( Pr=cr (~0,02 for motorcycle tyres on tarmac) * m * g ) and the most important the incline ( Ppot = m * g *  v * sin (inline in degrees) ). The mass m is of course driver together with the wheel. With this and the distance and needed time one should be able to "estimate" the needed power quite acceptable. Maybe measuring the incline can be a bit tricky - maybe some online maps give accurate enough height meters?

So with this formulas a Gotway ACM with 1500W sustainable power should be able to go up a 10° (18%) incline with 100kg load (including the ACM) with a speed of 25 km/h. The KS16 with 800W sustainable power should only be able to make 15 km/h. Also the KS16 should reach higher speeds (peak power) but overheat...

[HEC]

6 minutes ago, Chriull said:

Maybe measuring the incline can be a bit tricky - maybe some online maps give accurate enough height meters?

Probably would be easier to use "Bubble Level" or similar app on your mobile assuming the inclination is same on most of the hill.

[US69]

For Me all this numbers are a good joke.....and not testable....

 

When you take to numbers that we are working with a max of 67,2 Volts and in the Moment some wheels are delivered with a 10Amp Maximum draw batterie....

This numbers alone tell me that you can never reach the anounced Maximum Wattage of 3000......

 

I told it in another thread also: The KS16 is announced with 800/3000 Watt....but in the english instruction Manual it says it's Maximum is 2400 Watt :-)

That is a little nearer to the real wattage you can draw  from a 16S4P Pack! (and that even only for a very short Moment)

 

 

[HEC]

@KingSong69 Most of the batteries though have double C (current) ratings - one for the sustained current they can provide and one higher peek current for max 10 seconds so those peak currents can accommodate for peaks in motor wattage. Also the English KS16 manual could be incorrectly updated OR there could be actually differences in configurations (controller board setting or motor specs - speeds vs torque?) between Export and "Chinese" version?

[esaj]

Quote

I told it in another thread also: The KS16 is announced with 800/3000 Watt....but in the english instruction Manual it says it's Maximum is 2400 Watt :-)

That is a little nearer to the real wattage you can draw  from a 16S4P Pack! (and that even only for a very short Moment)

Actually, with 16S4P having 10A (continuous) / 20A (max) safe ratings, you can pull roughly 2400W (60V * 40A) continuously and around 4800W at max for short periods. The thing is, the batteries don't stop magically giving current at those values, it's just what the manufacturers state as "safe operating limits". For example, if a cell has 40 milliohm internal resistance, and you have 16 of them in series, the total internal resistance is 16 * 0.04ohm = 0.64ohm. Let's round it to nice even 1 ohm to account for resistance in wires & connector, and short circuit the battery when it's at 60V. The current running in the circuit will be 60V / 1 ohm = 60A!  So it won't magically stop giving more current after 20A, it's just that above the safe operating limits, the battery could very well overheat or get otherwise damaged (if used for longer periods than a some amount of seconds).

[OliverH]

4 hours ago, Chriull said:

 

I'd say that for us users the available power brought "from the wheel to the road" is the most important number.

And for this we'd have the peak power (with overheating) and the sustained power (temperature of the wheel settles in a "tolerable" range).

Since most of us do not have a dynamometer the only way for us users to verify this numbers is to search a quite constant long enough incline in the neighbourhood. And then measure the max reachable speed possible at this incline. And this with and without overheating (so best at a "defined" ambient temperature).

With the powers for the air drag ( Pad=0,5 * cw (~0,78) * roh (~1,25) * A (~1 m²) * v²) rolling resistance ( Pr=cr (~0,02 for motorcycle tyres on tarmac) * m * g ) and the most important the incline ( Ppot = m * g *  v * sin (inline in degrees) ). The mass m is of course driver together with the wheel. With this and the distance and needed time one should be able to "estimate" the needed power quite acceptable. Maybe measuring the incline can be a bit tricky - maybe some online maps give accurate enough height meters?

So with this formulas a Gotway ACM with 1500W sustainable power should be able to go up a 10° (18%) incline with 100kg load (including the ACM) with a speed of 25 km/h. The KS16 with 800W sustainable power should only be able to make 15 km/h. Also the KS16 should reach higher speeds (peak power) but overheat...

With this formulary we set balancing power to zero. Than we've a voltage drop while driving the incline. The max speed should therefor constantly decrease. 

[US69]

2 hours ago, HEC said:

@KingSong69 Most of the batteries though have double C (current) ratings - one for the sustained current they can provide and one higher peek current for max 10 seconds so those peak currents can accommodate for peaks in motor wattage. Also the English KS16 manual could be incorrectly updated OR there could be actually differences in configurations (controller board setting or motor specs - speeds vs torque?) between Export and "Chinese" version?

Sorry...i have to disagree this time for the peek Ratings :-)

Each 18650 Batterie is rated with it's own C Rating and normed for a max "continuous" Discharge...for example the ACM16 with 820wh with the Panasonic18650GA with a max discharge of 10A...continiuous

see here:

http://www.dampfakkus.de/akkutest.php?id=609

What you are talking about...the "Peak" or "Pulse" max discharge is Unfortunately not "standarized/normalized" in any way...."Peak" can mean 5 seconds, 10 seconds but also 1 millisecond...no one knows

The "real" Batterie Producers like Samsung, panasonic, sony etc NEVER EVER give an amount of this "Peak/pulse" max discharge...they only rate "continious"

This "Peak/pulse" Thing is only done by "unserious" Batterie "re-labelers" and re-sellers, which give the same Batterie a new fancy look......i Name here for example the Company "Efest"...

They gave Labels like 20A continous/40A max peak discharge...for a Batterie of Sony which has a max discharge rate of 15 Amp!

(a Little)More about this pulse/Peak here:

https://www.e-cigarette-forum.com/forum/blog-entry/battery-pulse-ratings-are-useless.7473/

 

And even if you have the abilties to get some "Peak" out of the Batterie....try to do the math not for a full Batteriepack 16S4p with 67 Volt at 10 Amp that can give =2680Watt .....if you look at 60 or 55 Volt it even gets a lot more absurd.....Never ever you are able to reach 3000 Watt with them

So (even for me ) this max Wattage at EUC Motors is in the same ligue as Batterie Peak-Level: Pure Marketing :-)

 

 

[esaj]

I believe that the motor ratings are more or less imprecise anyway, a motor rated at 3000W max is not going to blow up at 3000.1W etc. Someone (@Jason McNeil ?)  said in the past that IPS at least used to market their motor power just based on how much power (in theory) the batteries could deliver, that's why the older models say 1000W motors... The exact motor power is probably not a specific number anyway, as it will depend on a lot of factors, and I believe motors are "individuals" similarly to electronics components and computer CPUs. You have some range (typical/min/max) for each attribute of the component within which the (approved) components fall, but there will be some variance between the individual components, be it a motor, an op-amp or a computer CPU.

In the CPU-side, the companies have all sorts of other tricks too. The different speed CPUs actually come from the same silicon-slice, but the ones that still work with higher frequencies usually come from the middle of the slice, and the slower ones around the edges. Actually it could be that the Intel I3/I5/I7 all come from the same slices, but are modified in the manufacturing process. A more cheaper consumer-models could be the same high-end model with some on-chip cache-memory disabled (think Athlon vs. Duron Applebreeds a bit over a decade ago, the Applebreeds were actually Athlons with 3/4ths of L2 disabled, that could be re-enabled by filling the laser-cut holes on the chip holder with graphite to re-connect the rest of the L2-cache ) or one or more cores disabled. Sony PS3 (or was it 2?) had 7 cores but actually the processor chip housed 8 cores. One of them was disabled, because they found out that they had lots of defects where one of the cores wouldn't work but the other 7 did, so to push down reject-rates and make manufacturing cheaper, they altered the process to disable the defunct core, or even if all the cores were working, one of the working cores (or something along those lines, don't remember that good anymore).

Anyway, similar things could be done with motors too; test a few of the batch to determine some "range" of continuous and/or peak power the motors can withstand, pick a slightly lower number and stamp them as such (to allow for some deviation in the individuals). Some of them might start to fail at the "official" maximum power, others might be well able to withstand even more (and if they don't use a lower number, some could start to fail before the maximum ). If you've got a "bad" batch of, say, 1000W continuous rated motors where most cannot withstand that, stamp them as 800W and sell onwards...

I think (but don't know for sure) that the rated/maximum power-rating of the motor itself isn't that relevant really. Consider that I ride >30km/h on a Firewheel-motor rated at 550W (or 600W, depending on the source) continuous power. The parts I'd expect to fail are the windings (overheating and melting the insulation, shorting the coil), otherwise the power shouldn't "hurt" much else? High overvoltage could of course cause strike-through at the insulations of the coils... Too high speed could cause poor quality bearings cut maybe? Magnets or hall-sensors get knocked loose. But those aren't really power related.