What ESC Manufactures Don't Want YOU to Know

[@adamwasserman3805]

Hi! I'm working on an RC aircraft design optimization code, and I'm trying to create a simplified mathematical model for an ESC. I am modelling the entire battery-ESC-motor system as a DC circuit, where the ESC acts as a Buck converter (Pin = Pout, Iin*Vin = Iout*Vout). So for example, for half throttle (half duty cycle), Vout = 0.5*Vin and Iout = 2*Iin. However, after watching this excellent video, I'd like to add an efficiency term to the ESC to model the effects of partial throttle. The problem is that your data provides overall system efficiency as a function of throttle setting, while I need to understand the efficiency of just the ESC (I have separate mathematical models for the motor and propeller). Specifically, I need to understand what exactly efficiency means for an ESC. If efficiency is measured by Pout/Pin across the ESC, how would I solve for Vout and Iout? I see 3 possibilities: 1. The ESC switching losses reduce voltage, so Vout = efficiency % * throttle % * Vin. Iout remains the same as for the idealized Buck converter ESC with 100% efficiency. 2. The ESC switching losses reduce current, so Iout = efficiency % / throttle % * Iin. Vout remains the same as for the idealized Buck converter ESC with 100% efficiency. 3. Some combination of the above. Do you have any tips for how to mathematically approach this? Thanks!

[@RCexplained]

Pout/Pin = efficiency. Is how I'd handle this.

[@rcandfun242]

Interesting! I'm no expert on esc's but most speed controllers use mosfet transistors to switch the motor coils on and off. Mosfets can't switch infinitly fast. The gate of the transistor has a specific capacity that has to be charged/discharged by the mosfet driver IC (if it even has a driver) in order to turn it on/off. So my theory why some esc's can switch a lot faster than others is that they use (better) drivers and transistors with a smaller gate capacity. By the way, are there already hobby esc's available with Ganfet-transistors? Gallium is more expensive but the transistors switch faster and are much more efficient for high power applications.

[@RCexplained]

I am not sure if Ganfet-transistors are being used.

[@hobbycenter61]

I've always use external bec and isolate ESC BEC, plugging only signal wire on receiver

[@RCexplained]

That works.

[@RCPhysics]

Awesome as always!

[@redndeyes]

Yup

[@RCexplained]

Thanks again rhouse21!

[@LightCarver]

Also there is an amp draw limit on a BEC. Receiver and things plugged into it could add up to to much; servo(s), lights, sound, winch accessories etc. Need some head room too... if the BEC V drops on a maxed out circuit the loads may pull over the amp limit.

[@druskee2380]

Can you do a vid explaining how shock positioning/spring rate/oil weight etc can give you better turn in/exit speed on a corner?

[@RCexplained]

I can add this to the list.

[@colin1992]

Interesting! I guess theres things that they dont want us to know when we should know them so we can know what applies to what for our rc hobby

[@RCexplained]

Great point!

[@xibidit]

On my esc that blew up, there is no capacitors on the motor side of the esc. Is that normal?

[@patrickmckowen2999]

Good info 👍

[@RCexplained]

Thanks 👍

[@LawrenceTimme]

Can the reciver overheat if your servos are too powerful

[@RCexplained]

The receiver must be able to handle the load as this servo load is bridged on the receiver circuit board.

[@LawrenceTimme]

@@RCexplained yes i thought so. 🤔 Doesn't that mean if you have a very powerful servo and bec you could damage the receiver?

[@RCexplained]

Yes you can damage the circuit that carries the power to the servos.

[@onclepete7888]

Great info, thank you.

[@RCexplained]

You bet!

[@cesarguerra6039]

Hello Ryan, greetings form Spain.Always see your videos, very useful and interesting topics. Im buying components for a 1/10 scale buggy DIY. I bought a 4 poles 3660 2600 KV brushless, SL, which I will use on 3s. Im missing the ESC and not really sure what parameter apart from Amps( I want a 120A) can I look into in order to decide(resistance?). I have two hobbywing in mind: MAX10 SCT and Quicrun 10BL120. The price difference is 40 EUR, Is this really better the MAX10? I want to upgrade it to big tires(13mm) both will be ok or this use? The MAX says good for monster truck the othe does not say. thanks!

[@RCexplained]

Choose an esc based on voltage and current. Then get the features that you require.

[@robertkotevski9649]

Great video mate

[@RCexplained]

Thanks 👍

[@Eden_M]

Hey Ryan, thanks for the video, what about powering a cheap 3ch receiver on 2s lipo or 2s li-ion? 8.4v is way too high, I don't use any servo, I only need radio signal for throttle. I'm thinking about using a resistor, I know ohm's law, but overall what do you think about this approach? Thanks!

[@RCexplained]

I do this using an externally mounted BEC. This way I can run 2s/3s/4s doesn't matter. It all gets dropped to 6.0v at the receiver. If your receiver is rated for this voltage, then you don't have an issue.

[@tommcdonald6371]

Bro I hope u c my comment please do one on brushed motors there's so much we don't understand about gearing torque and turns u the best help ever thanks for ur service

[@RCexplained]

Noted, it's a bit challenging for me to do a video on brushed motors, as I do not have too many of these kicking around any longer.

[@truthonlytv2862]

Nice background nice change compared to your living room lol seriously nice job that's one way to raise the bar for yourself. Btw watched you for awhile this is the first comment I've ever made lol..

[@RCexplained]

Thanks so much and for taking the time to comment!

[@Mano_421]

That’s pretty interesting, good video!

[@RCexplained]

Glad you think so! Thanks Giovanni

[@rcmod642]

noice I'd appreciate it if you could make a video about the fake CV joint.

[@redndeyes]

Fantastic idea

[@RCexplained]

What are you referring to as fake CV joints?

[@rcmod642]

@@RCexplained In most of the RC industry, Universal Joint is called CV Joint, but Universal Joint is not able to do constant motion. The same goes for the double-carden joint. A 1/5 vehicle like an MCD has a CV joint with a ball like a real vehicle, and I think we need to distinguish terms between CV joint and Universal joint. I would like to ask you to experiment with how much grip loss occurs due to the vibration of the angle when the Universal Joint is used on the front wheel. kzbin.info/www/bejne/nZ65ZaStgcuCg7s

[@andyjonathan2486]

I’m pretty certain you’re an electrical engineer.

[@RCexplained]

Close! Mechanical

[@andyjonathan2486]

@@RCexplained cool! I’m a practicing ME, but I usually stay on the FEA/stress/strain/fatigue side of things for work, and only dig into the EE side of things when running my 8s XLX2/2028 1/5 sand buggy at the beach. Keep it up! I LOVE THE CHANNEL!