Found our motors, cheap

I did calculations on speed and if Evolve is running their motors on max, the motors that come with the board are 140Kv - I'm 100% sure of this.

I wonder what would happen if you replace the existing motors with 2 170Kv Ollin motors instead (work fine, burn out ESC or run at reduced rpm?). I'd love to get the increased 32 mph top speed on 97mm wheels and replace the existing batteries with the VTC6 10s4p pack. If everything works accordingly, it would be my ultimate board. No sag, perfect speed and awesome range.

 

How did you do the calcs mate? I've got 4 of the 140kv motors from bangood and they look identical.

I worked the KV for the evolve motor to be 150. Can we compare calcs?

 

I can go into more detail if you want, but here is a rudimentary way to see. The results match up identically with Evolve's wheel size:speed chart. Try changing wheel sizes and compare it - also, efficiency only comes into effect after battery has depleted to around 70%

 

I thought KV was RPM per V so when i go through the menu on the remote and get the motor RPM on full trigger pull in GT mode i get around 5400RPM. the BGT Battery is 36V so.... 5400/36= 150. That's my understanding.

The motors from Bangood are as follows.

 

My understanding would be that they might be measuring from a LiPo cell. The power delivery is a bit different between LiPos and Li-ions. Though a LiPo cell should give you better delivery meaning a higher RPM. How exactly did you get the RPM of the motors - maybe the measurement is inaccurate? Because 140Kv would actually mean 5040 rpm not 5200, they get the 5200 from LiPo (5180 rounded).

 

Note KV is a rough estimate and motor to motor will vary. So the 140KV and the 150KV are so close that I'd call them the same actually. And Milly's calculation is correct, its RPM at the motor. But you also have to measure the volts realistically at the battery to do the calculation correctly. But I'd say you both are correct since motor to motor variation does occur.

 

You can get onto the motor RPM by entering the hidden menu in the remote. you can also see the cell balancing for each cell. KV = RPM/V that's how on the data sheet for the 140KV motor it is 5200/36=144 (the must round up or down to the nearest 10 KV)

The BGT battery's are advertised as Li-ions too!

We are both trying to figure out different things here. haha....

 

Would you say....that those motor the 140kv option, would be the same? I have 4 of them ans they look identical but i have not much understanding of the 'Watts" Evolve advertise 1500 watts per motor and the 140kv ones i have bought advertise at 1200 Watts

 

I'm going to check it right now.

 

here is the how to navigate to the hidden menu. let me know your motor RPM please on full trigger in GT. probably best to have no wheels etc on, just the motor running on it's own.

 

Yep, mine were fluctuating between 4900-5040 but keep in mind my battery is at 70% (38.5v) so the I assume it would be close to 5200 or higher at full charge. I had no idea about the secret menu, that's awesome!

BTW: You guys might like this thread I started over at the esk8 builders forum. Its something I plan on doing later but hopefully you guys find it interesting.

What would happen if I changed the motors? {Ultimate Evolve GT}

 

Ahh ok that is interesting, mine are around 5400 on 100% charge GT. say for example 5000RPM at 70% with a battery voltage of 38.5v would then mean....
5000 / 38.5 = 129.8KV cool! so i think 140 KV motors would be fine.

Evolve do state it's a 36 v battery, i think 36 volts is that batteries usable voltage. so just for examples sake say you get 5000 RPM at 70% with 36 volts that would mean 5000 / 36 = 138KV.

I know where you can get identical 200 KV motors if you are interested.

 

Cancel that, i've seen your thread on ES8 builders, I can confirm for you that the motor plugs etc are identical

 

Just so you know, 36v is the nominal voltage for the battery pack. At 100%, the battery could be anywhere between 40-42v since the charging voltage is 42v.

 

The Wattage specification is "horsepower", or what maximum power level the motor is rated for without melting into a puddle of copper. From what I can see in the "amp" menu of each motor, we are not even coming close to it. Its what I can see as something meaningless for us. We'd need to be pushing 33 amps to each motor with a 36v battery to reach the 1200watt rating for the cheap motors we found and 41 amps for the Evolve motors. But the watts makes sens and are very important on smaller motors that have a way lower watt rating which can easily be overdriven by the designer / user.

Watts equals Amps multiplied by your battery voltage or (Amps x Volts).


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Your brushless motor should have a watt rating on its spec sheet, something like “180W”. This means that that is the amount of “horse power” that it should produce safely. Running anything over this rating could damage your motor, especially over a long period of time.

Learning Brushless Motors
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Ahhh ok cool, in that case the difference the Voltage makes on the motor KV is pretty big, cool! Well I've learned something new which is awesome. I will be interested to see your build with the 200KV options. I will be following closely

 

If I did the 200kv motor option, I'd buy an extra set of rear trucks and motor mounts. Buy some extra marine quality quick disconnects for the motor / controller wires. That way you can have the 140kv for your AT setup that's on a truck complete and the 200kv on another setup for street. Quick change over. Then you have the best of both worlds that change over fast since your belts stay on the setup.

 

The issue with that is that there seems to be hot glue or some substance where the wires go to the enclosure. How would I resolve that? I'd like to keep the board as water resistant as possible.

Also keep in mind I'm only 14. I need to conservative with my money since I don't even get paid minimum wage to work - not until I'm 16. Along with not being able to spend too much, I'm not super experienced with electronics - most of my knowledge is from reading and tinkering but most of you have vastly superior knowledge compared to me.

 

In this case I would stay away from making bigger changes like a full battery replacement. But if you want to take the risk.... please don´t use VTC6... they have a big heat problem with high discharges... very small amount of cycles... Also you don´t need a higher discharge rating as 20A since the board is limited to 65A max, that´s 13A on 5p10s or 16A on 4p10s per cell. I used the LG HG2 as 5p10s (yes the bms is kissing the power board but it fits ). Works perfekt in all conditions, except it´s getting cold very early in winter since it´s not working like a toaster like the original one(or the VTC6)

 

Is there any particular cell you would recommend? The current cells already have horrible voltage sag and with 200kv motors it would be much worse.