Hi everyone, my name is Ray and am 30 years of age; I live in Colorado. I been in RC for about 15 years but I been out for almost 2 years now and I am just getting back into the groove of things. When I left the scene, BL and lipo was just heating up and now it has just exploded... very cool to see! So I have a few questions if you wouldn't mind helping me out a little. You can even just give me links; that will work dandy.

Can someone give the the scoop of the numbers on BL motors. I am reading up on them but am very confused.

For example: The Lehner Basic 5300 and Basic 4200 motors have the same peak RPM capabilities, but since the 4200 has a lower RPM/V and can run on more cells, it will have more torque than the 5300. However, in small car applications, the 4200 will have lower top-end speeds on only 6 and 7 cells than the 5300 on the same number of cells.

Motor Power(Watts) @ Amps RPM's/Volt
Basic 5300 700 Watts @ 55 Amps 5300
Basic 4200 600 Watts @ 45 Amps 4200


So what the heck do I look for in the numbers and what do they mean? I read that above statement yet it makes no sense to me at all. What makes a BL motor have more speed VS more torque and so fourth?

Also, I heard something about you need a higher voltage battery for higher kv motors; is this true?

"Not having enough amps in a lipo pack means that the? motor is trying to draw amps that the pack cannot deliver and thus causing the pack to over heat and BOOM!!!" This is what I am referring to, so how do I make sure all my "numbers" are good to go?

I'm thinking about putting a Novak HV 5.5 or Novak Ballistic 5.5 or motor in to my Slash and am wondering if anyone has tried this yet. I noticed that the HV 5.5 has 800 Watts and 3,700 RPM and the Ballistic has 420 Watts with 7,400 RPM. I see huge difference in the the RPM and Watts on both, they are like way two different motors even though they are the same turns... 5.5? I don't know too much about BL motors at all but I am trying to learn more.

HV 5.5 - 800 Watts and 3,700 RPM (11.1v would make it max out on 41,070 RPM's?)
Ballistic - 420 Watts with 7,400 RPM (11.1v would make it max out on 82,140 RPM's?)

Do more Watts translate to more torque beings the Novak has higher Watts but lower RPMs?

I know sensored motors are more wild than sensorless systems, basically that's all I really know about BL besides the turns like on the brushed motors.

Ray

First of all, what are you looking to do? Are you racing cars or are you looking for something for a plane or boat or something?

Watts=Horsepower. They are the exact same thing, just a different unit of measure. Like inches and millimeters.

The HV stuff is designed for the bigger 1/8 scale cars. They have huge torque numbers but they get the speed from the fact that most are using a minimum of a 4S lipo. HV motors and the Ballistic that you meantioned don't really compare, they weren't meant for the same application. Second a 5.5 BL motor in a Slash is simply INSANE!! you don't need that much power.
What are you looking to use for batteries? 2S, 3S? Are you going to race?
Personally if all this is going into a Slash I would get the HV stuff out of your mind because that's not really what it was meant for. I don't think the shaft sizes are even the same. I can't say 100% that it won't work though.

Why do you say sensored motors are "more wild" than sensorless? they make wicked fast motors both ways

Thanks guys.

@ Wingracer
Thanks man, so more Watts means more power, well that's good to know. I do land RC's...

@ Racer1812
On another note, I'm using 2s and 3s and anywhere from 20c to 35c so far. HV is outa the mind, for now anyways. But I have always been a speed freak so "too much" power is not in my vocabulary. I am gonna be bashing more than racing so insane power is fun for me. Been looking at the Ballistic 8.5 but I fear that won't be enough power . I actually thought I put the opposite on the sensor thing, I know sensorless motors are very wild... so yeah I meant to say the opposite, but I do know do that they are both extremely fast motors.

So whats the difference between the Novak Velociti 5.5R and the Ballistic? They are both speced at the same Watts and kv as listed on Novak's site.

Ray

The ballistic series allows you to change stators. So you can change from a 5.5 to a 4.5 or 6.5 or whatever by just changing the stator without having to buy a whole motor.

Oh cool, thanks Wingracer.

So I did some numbers and I understand this a lot more now. How would I figure out the Continuous Current and Peak Current being drawn out to make sure my ESC will be safe. I don't have BL setup yet, but I wanna make sure I know what to look for in an ESC... I know the higher the Continuous Current on the ESC then the better.


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Continuous Current and Peak Current Example:

Novak Ballistic Spec Brushless Motor 13.5T
Watts: 195
kV: 3,300 RPM/volt (unloaded)
Maximum RPM: 50,000
24,420 RPM on 2s Lipo
36,630 RPM on 3s Lipo
48,840 RPM on 4s Lipo

Continuous Current: ???
Peak Current ???
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With the Novak Ballistic Spec Brushless Motor 13.5T example, the Watts still stay at 195 even on 4s with all those RPMs?

EDIT: As for my first post about BL motors, I now know. And what I said didn't make sense; now makes total sense to me . I am just trying to figure out how many Amps I would be using in any given setup now.

Ray

I don't run anything but 2S so I can't help with anything above that but any pack with 150 continuous amps should work just fine with even the wildest motors. A 5000mah 30C pack will get you there. Others will chime in if I'm way off base

The wattage will go up considerably, well assuming it doesn’t burn up, I don’t think they are designed for that much voltage.

No real way to calculate maximum current, too many variables, gearing and such.

Thank you all very much, very helpful!

Ray

Humm, not at all sure about this….. but Novak lists wattage at a given voltage. Theoretically you can divide the watts by volts to get amps.

But it seems it would take more understanding of the test conditions, not sure how they arrive at the wattage number, how hard/hot the motor is being driven, adjustment for actual battery voltage under the load (rating is at 7.2v), adjustment for motor efficiency, whatever else I’m not thinking or aware of, etc.

Anyway I tried some calculations and compared to my race battery charge experience. I’m using roughly 50% of the amps from a simple calc ignoring all of the unknowns I mentioned. Which seems at least a somewhat reasonable ratio of average to maximum current draw for an offroad race. Perhaps this approach could be used as a rough guide to maximum current. Maybe with some safety factor.

What do you guys think? Anyone with a data recorder ever tried to compare max current to the published specs like this?

I have ran alot of brushless motors from novak 3.5 to 13.5 . The fastest motor I have ever ran on 2s is the lehner 5300 . I think the ratings on some of these motors are bull. The best way to tell if your pulling too many amps is battery temps. If the battery is getting hot (over 120 degrees) you need a battery capable of more amps. The sensorless motors can be geared alot harder than the sensored motors . Temps will tell you if the gearing is right on motor and battery and speedo.

So with that said, a 2s-20c lipo that is over heating on a hotter motor setup would fare better with a 2s-40c or maybe even a 3s-20c lipo as along as the ESC is rated for the higher voltage from the cells?

I guess that makes more sense now. So if the battery is being drained and overheating by a hotter motor then you must "feed" the motor with more power to produce efficient temps and over all performance. So its not far off from Nimh and brushed setups then.

What are some good Sensorless motors out there?

You think I can put a Lehner 5300 in a slash, I mean; will it fit? Where is a good place to buy Lehner motors?

Ray

Yes it will fit. Those motors are alot shorter than a normal motor.They have a bigger rotor. Running 3s is out of the question on these as it will put out way too much power and will destroy a tranny quick. Fine design sells them but probably other places too. Hacker sensorless motors are really high quality but you pay more for them. I have ran hacker 6 turns and they aren't as fast as the lehner 5300 but last forever. Another option is to run a mamba max with the 7700 motor as it's pretty fast. I have ran it on 3s (not recomended) and it's crazy fast.

Nice lol, so where is the best place to get Hacker motors for the money at?

Ray