What brushless motors are being chosen?

C

cmoalem

Active member
So the TP Power 5860 (the 1kVa version with 12s) was tried tried by AlexLTDLX and gave some results with that Vortech Sc 2 trim headunit ... then a year later the TP 5870 ( 0.75 kVa version) was picked.

@AlexLTDLX have you noticed a worthwhile difference?
(worth it? last night I ordered in my haste a TP 5860 ... it was saying "only one available, lol. Hours later I discovered you switched.)

Anyone out there eyeballing a different electric motor?
 
Since I didn't know what any of the limits were I went with the slightly shorter 5860 only because it had a higher max rpm - 50,000. Once it became obvious I was not going to be able to get anywhere close to that with my vortech, and not wanting to fail (at least not put my "best foot forward" in public on youtube) I went with the 5870 - which has a max rated rpm of 40,000, but in theory more torque. But both motors have the same max peak power rating - 15,000 watts (20hp). The difference is literally only 1 cm in length. And since we haven't hit saturation (motors are apparently limited by magnetic saturation of melting the windings - whichever comes first; usually saturation), I would assume that the 5860 should also be able to support my current power level - which is about 650 hp. Ultimately, the 5870 should make a little more - maybe 10% or so. Assuming you run to max. But let's say you choose a small compressor that needs more rpm, then the 5860 is actually the better choice. It's all about balance, but it's also a certain amount of, "nobody knows because nobody's tried it yet."

Like Yogi Berra once said, "In theory, there's no difference between theory and practice, but in practice there is." Lol. I should make that my sig. If we have signatures enabled... I'll have to check.
 
That's the thing - nobody knows. I feel I've only scratched the surface of what's possible. We will all discover together. And I have to admit, it's nice not feeling completely alone in my progress and decisions!
 
What are the actual differences in the TP5870 10S, 12S and 16S version of the motors? I plan on running a 16S setup but my friend wants one too and he may not have 16S to start . Also what's the best price (without ordering from china) I hate waiting for shipping, lol.
 
Basically the primary difference is in the voltage capability of the motors. And the higher the voltage the less current. Which effectively means the ESCs and such are cheaper. I would go for the 16s no matter what. You won't be able to find an ESC that can handle the current at 10s. Basically it all comes down to watts. And watts is a function of voltage times current. So if the goal is say 10,000 Watts, if you have a hundred volts you only need 100 amps to hit that. If you only have 10 volts then you need a thousand amps. Which would also mean heavier gauge cables and connectors and everything else. Even more expense.

And I actually don't know of any stocking retailers for TP power motors. I can vouch for R Mamba brushless on ebay. The guy's name there is Rafael, and he's really helpful. Tell him you know me (the guy who built the electric turbo) and maybe he'll be even more helpful. I bought a bunch of stuff through him. He also has helped with warranty claims as much as he can.
 
That makes it so much easier, thanks. I was looking at his listings on ebay and noticed it was from china. How long did it take to ship? His prices are about the same as this site https://www.mytobbies.com/copy-of-tp5870-v1-900kv-10s-max-8mm-shaft.html but I am always a bit iffy about giving my credit card information to sites I've never heard of. I'll order 2 of the 16S TP5870 from him and I'll message him first and mention you. I've definitely fell into this rabbit hole and learn something new everyday, lol.
 
It wasn't too bad, irrc. Like 3-4 weeks or so. FWIW, I recommend the 750kv - it seems to strike a nice balance in the speeds we can reasonably hit under load.
 
considering the current top runner blower having a gilmer setup (28T pulley?) :

how about slapping a 150T pulley on this one and flanging it on the P-2 :
maytech.cn

In Stock Maytech IP68 Waterproof MTI85165 200KV Inrunner Brushless Sen

Specification: Model No. MTI85165-200-WP KV 200, if you want other KV, contact agnes@maytech.cn Max Current 300A Input Voltage 6-12S Lipo (25-50V) for 200KV, 6-16S Lipo (25-67V) for 150KV Max Output Voltage 10.5KW Shaft Keyway Shaft Hall Sensor Without, if you want hall sensor, contact...
maytech.cn maytech.cn


looks BIG

available here as well (I like the datasheet!):
www.aliexpress.com

808.0US $ 20% OFF|Maytech Water-cooled 85165 Motor Inrunner Brushless Sensorless Motor For Electric Surfboard Jetski Efoil - Smart Remote Control - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com

and the next mo paua version here:
www.aliexpress.com

1045.6US $ 20% OFF|Maytech 18.8kw Powerful Motor Mti120116 Water-cooled Sensored/sensorless Brushless Inrunner Motor For Electric Surfboard Boat - Smart Remote Control - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com

(HEAVY!)
 
Last edited:
I don't think that motor will be enough to do much. Before I went the electric turbo route, I had a 2.3L Whipple on the car (in fact, it's sitting on the floor next to me as I type). Those rotors are heavy, and relatively speaking, these blowers aren't as efficient as centrifugal compressors. And the main benefit of a Whipple - or any positive displacement blower - is instant boost. Something that's a moot point with an electric centrifugal blower.
 
well ... they seem to have enough torque to power hydrofoils (lifting adults above the water while gliding along).
So I thought with the right gilmer pulley you can make that P-2 centrifugal charger spin! (no?)
 
I apologize in advance if I'm being too fundamental, but energy is everything. In this case, watts is the most useful measure, because it has a direct mechanical analog - 746 watts equals 1 horsepower (even more fundamentally, heat is energy, but that can lead you down the path of joules, calories, etc). Watts is our friend. Let's say you're applying a million foot pounds of torque to the base of a mountain with a lever. The mountain doesn't move; therefore no work is done. Now let's say you're applying 1,000 ft-lbs AND 2,000 rpm to a large rotating super-hard steel blade with teeth. 1,000 ft-lbs at 2,000 rpm is about 380 horsepower or 283,480 Watts. That blade will (eventually) grind the mountain to dust. Work is being done.

So in our case, we want enough torque at a specific rpm to turn a compressor. Centrifugals like rpm. Let's look at the approximate actual numbers from my setup. So far, we're spinning the impeller at ~28,000 rpm. And it takes about 13,800 watts to do that (at the motor - the power going into the ESC is considerably more). So that means we're making about 18.5 hp going down track. 18.5 hp at 28,000 rpm is only 3.5 ft-lbs. That's because in order for work to be done, you need both force AND motion (in this case, rpm). If we have a compressor that is heavier and needs less rpm - let's say like a positive displacement blower - then you'll need more torque. Like the electrical relationship of current vs voltage, where to make 13,800 watts you either need 13.8 volts at 1,000 amps or 138 volts at 100 amps (the 138 volt version can get by with smaller cables because the voltage is traveling "faster" through the cable - not really, but it's helpful to think of it that way); the mechanical variant needs either a lot of speed to have less torque or a lot of torque and little speed. And torque breaks things; speed, assuming bearings are fine, is much easier to manage (like higher voltage).

Hopefully this makes sense, I'm just typing on the fly. At the end of the day, keep this in mind - Watts is everything, high current is harder to deal with than high voltage and high torque is harder to deal with than high RPM. Both of those issues (current and torque) come with the caveat "up to a point," but we're not coming close to that particular point in what we're trying to do. At least not yet.
 
I'm learning a lot too. The most exciting thing is, we have a viable proof of concept, so we know it works. Now it's down to finding the "best of the best" for each part - compressor, motors, ESCs and battery packs. Of course the "best" for one setup isn't best for another, but if we all figure out the pros and cons of individual pieces, I can easily see people "mixing and matching" different motors, batteries and ESCs to get to whatever goal they want to. And prices should come down, too.
 
and here the source (the German company behind the MGM LMT motors) :

Lehner Shop

www.lehner-shop.com www.lehner-shop.com

I like their calculators and rpm(KV) table btw a lot!

Lehner Motoren Technik - Motor calculator

www.lehner-motoren.com www.lehner-motoren.com

interesting to see the differences for a 3080/5 (1050KV) @50000rpms,50V,300A and the 3080/7 (750KV) @45000rpms,60V,200A
the difference in input power is significant ...
BTW the 3080 "non LK/Hi Amp" (without that air cooling fan at the top) has similarities in dimensions to the TP power 5870! (just 4mm bigger OD but weighs like 50% more!!!)

The LMT 3080 is advertised at 30kW on the mgm site ...
If you look in the calculator (for 3080/5 @50000rpms,50V,300A) into the respective data table (and scroll down) they mark one line in "green" with 691A current draw @50V and ~33kW power! (I assume with some water cooling and monster cables this monster delivers! Good that they use 6!)

In comparison the 3080/7 ((750KV) @45000rpms,60V,200A) maxes (marked "green") out at 435A current draw @60V and ~25kW power!

(soooo ... the added diameter and weight actually "do" something as well ... I start liking the LMT 3080 750KV variant actually!)

In comparison: the TP 5860 / 1000KV I got is specified @7200 W continuous / 15kW burst/max ... probably with cooling (and as demonstrated by Alex who ran it at ~23kW) it can be in limits "overclocked" too. (but most likely his old flier ESC was the bottleneck!)
All in all : TP power motors look now like "half the price == half the outcome"! Same/similar can size and 2/3rd of weight ...

Another outcome: the "300-400 Amp" ESCs are not going "to cut it" for 50V (1050KV), but probably limit the input power too early! (probably that's why mgm is offering that monster 800A ESC (for 15s) now ...

The APD HV - Pro 16s might be just fine for the 750KV variant ...

The Lehner prices are a bit higher than on the mgm-controllers site due to 19% VAT included in the lehner shop!
 
Last edited:
Lol - I literally just closed the LMT tabs I had open before coming here tonight. I have to admit, I've never been able to get their calculator to work for me, and I find their specification process confusing. But it's obvious they're good motors and probably better than my TP Power; though even Steve Neu (the "godfather" of high performance brushless motors, and the guy I happened to buy my APD ESC from) said good things about my TP Power motor - and my experience thus far has been good; as opposed to my experience with Flier ESCs. If I was to step up (since it's looking like this APD ESC won't be maxxed out by the motor I have), I'd probably see what he has first - https://neumotors.com/ His motors/designs are the "gold standard" against which all other motors are gauged by. The biggest issue I have with LMT is their (relatively) low-voltage limits. But please don't take this even slightly negatively towards LMT - if Steve didn't have anything (I could afford/justify); they'd be my next stop. But at this moment, I think there's still quite a bit left in my current motor (I'll start a thread tomorrow expanding on what I've recently learned).
 
What is the most recent / consolidated thinking of motors to consider for direct drive of a small centrifugal compressor for a 2L engine?

I am thinking the requirements are:
  1. High RPM 50,000+
  2. High power (high volts, high watts)
  3. Large shaft ~ 8 mm
  4. Have we landed on sensored vs sensorless motors?
  5. Should we stick to 4 pole motors?
It seems that the best candidates are designed for 1/4 - 1/5 large scale rc cars from the hobby industry.

Are any of the motors in the table below top candidates? Any recommendations to explore? All of the options below have 8mm shaft. Any to cross off the list? Any additions? Other Considerations?

Motor ​
RPM max​
Max Volts​
Watts Cont / Peak​
Cost​
TP 5870 990KV40K too low for direct drive ?40V9,000 / 15,000$299
TP 4070-SCM100K nice8S = 32V3,856 / 7,600 too low?$239
TP 4070-SVM73K8S = 32V5,500 / 9,500$239
TP 4070-CM75K12S = 48V - 54V5,000 / 9,000$259
TP 5670-CM85K10S = 40V8,000 / 12,000$399
Castle 2028 800KV45K too low for direct drive?10S = 40V$274
Hobbywing 70125 560KVmy calc = 48 x 560KV = 27K?6-12S= 25V - 48V300A/2000A = 12,000 / 88,000$350

Now that this data is all in one place, if seems that the TP 4070-CM is the best option as it has both high RPMS (75K) and high power handling 5KW continuous at a less than $300 price point. does anyone know the RPMS of the Hobbywing 70125? I like that one just because of its sheer mass can help dissipate heat and handle so much power. If you provide other options from our collective wisdom, I will add them to the chart.
 
Last edited:
GTHound said:
What is the most recent / consolidated thinking of motors to consider for direct drive of a small centrifugal compressor for a 2L engine?

I am thinking the requirements are:
  1. High RPM 50,000+
  2. High power (high volts, high watts)
  3. Large shaft ~ 8 mm
  4. Have we landed on sensors vs sensorless?
  5. Should we stick to 4 pole motors?
It seems that the best candidates are designed for 1/4 - 1/5 scale rc cars

Are any of these good candidates? Any recommendations to explore? All of the options below have 8mm shaft. Any to cross off the list? Any additions? Other Considerations?

Motor ​
RPM max​
Max Volts​
Watts Cont / Peak​
Cost​
TP 5870 990KV40K too low for direct drive ?40V9,000 / 15,000$299
TP 4070-SCM100K nice8S = 32V3,856 / 7,600 too low?$239
TP 4070-SVM73K8S = 32V5,500 / 9,500$239
TP 4070-CM75K12S = 48V - 54V5,000 / 9,000$259
TP 5670-CM85K10S = 40V8,000 / 12,000$399
Castle 2028 800KV45K too low for direct drive?10S = 40V$274
Hobbywing 70125 560KVmy calc = 48 x 560KV = 27K?6-12S= 25V - 48V300A/2000A = 12,000 / 88,000$350

Now that this data is all in one place, if seems that the TP 4070-CM is the best option as it has both high RPMS (75K) and high power handling 5KW continuous at a less than $300 price point. does anyone know the RPMS of the Hobbywing 70125? I like that one just because of its sheer mass can help dissipate heat and handle so much power. If you provide other options from our collective wisdom, I will add them to the chart.
Click to expand...
I use a tp 4070 cm on my set up. Well I beleive till I disassemble it.. it was a 4070 normal motor and I was able to achieve 55k rpm on direct drive set up. But I changed for a castle creation motor
 
WB - are you coming out of your winter deep freeze? :)

I think sensored is preferred - it eliminates a bunch of issues. The LMT motors are great, too - just not easy to get. The biggest issue with the TP motors is that most of them are 6 pole motors (I believe), necessitating a very hgh eRPM, which is hard on ESCs.

I do think we want to stick to direct drive or minimal gear step up. I'm convinced that what we don't want to do is go with big ratio (5:1, 10:1) step up drives, because then the motors start getting very big and heavy (more torque, less rpm for the same power output) - and that gets difficult to package. Horsepower makes you go fast, torque breaks things.
 
You must log in or register to reply here.
Top