So this is my build:

Frame: XL5 V4
ESC: iFlight 45A 2-6S BLheli_S DShot600 4In1 CES
FC: CLRACINGF7 MPU V2.1
"VTX": Caddx Vista?
Motors: iFlight XING E 2207 2750KV 4S

I want to have an ESC replacement just in case, but im not sure if I should buy the same (I've heard and experience some trouble with iFlight) or buy another one... What should I do?

It's your call really. I refuse to buy iFlight electronics but if you've had no issues with yours then the easiest swap-over replacement without having to re-pin anything or get different wiring harnesses is to just get a spare ESC made by the same manufacturer as the one you already have.

(24-Aug-2021, 12:41 PM)SnowLeopardFPV Wrote: It's your call really. I refuse to buy iFlight electronics but if you've had no issues with yours then the easiest swap-over replacement without having to re-pin anything or get different wiring harnesses is to just get a spare ESC made by the same manufacturer as the one you already have.

The thing is, which one would you get? I don't like iFlight either but don't really know what to buy instead

I would look at amps, and pin break out … some only have a “plug”. This may seem rather simple, but in the event of that plug becoming damaged, it’s nice to have decent size pads to solder to as a back up.
Normally I would suggest a “reasonably priced, pretty solid” stack… but with the price of components… I would check some reviews first..

Right now stock is so bad I would wait, since you don't need one.

Keep checking to see if some good ones come back in stock.

I am using a Tekko32 F3 for a long time now, and it has been great! The newer F4 version has 45a ESCs, and 96khz PWM Freq. But they are out of stock, like most good ESC 4in1's right now. If you can find a Tekko32 in stock, I definitely recommend it.
https://shop.holybro.com/tekko32-f4-4in1...p1266.html

GetFPV has a HGLRC 48a Zeus board in stock, but I've never used it:
https://www.getfpv.com/hglrc-zeus-48a-3-...s-esc.html

Solo, from what I have heard (Bardwell, Kabab, Spatts). Anything over 48khz pwm is not necessary for 5” or larger. Smaller yes, but apparently it is due to the chip shortage and manufactures are using f4 processors in ESCs (giving higher kHz) and possibly using it as a selling point..
I maybe TOTALLY wrong, as I am still learning..

(24-Aug-2021, 06:32 PM)Rob Axel Wrote: Solo, from what I have heard (Bardwell, Kabab, Spatts). Anything over 48khz pwm is not necessary for 5” or larger.  Smaller yes, but apparently it is due to the chip shortage and manufactures are using f4 processors in ESCs (giving higher kHz) and possibly using it as a selling point..
 I maybe TOTALLY wrong, as I am still learning..

For my 5" I use variable PWM with low set to 24khz, high set to 48khz.  Seems to work good for me, letting it decide based on throttle input between the two. 24khz at low throttle for more torque, then it will auto change up to 48khz at high RPM for a slight decrease it power, but smoother motors.  With the F4 some might want to set High to 96k and let it go up that far. For me personally 24-48 has been working great.

I'm not sure when I first got this Tekko 32 F3, but I've been beating on it for a long time now and it is great. 

 I can't find one in stock, but that would be the ESC I point people to from my personal experience.

I think we will have to wait for manufacturers to put out some more stock.  I have an iFlight SucceX 50a ESC in a drawer just in case I need a replacement, but I would buy another of these Tekko32 in a heart beat if I needed one and they were in stock.

Variable PWM, that BLHELI-32? I havnt delved into 32 but YET… still messing with “S”…

Yes BLHeli32.  They offered variable PWM with version 32.8.  You can keep it set at one number, or use variable. With Variable PWM you set one number for High, and one for Low.  Then it changes between them based on your throttle/motor RPM.

So my Tekko32 ESC runs at 24khz when I am at low throttle for maximum torque, and changes up to 48khz when I am at high throttle so the motors run smoother/more accurate.

Here is a pic of it on my Goku Evo F7 AIO board :

High PWM is only useless on 5" quads at low RPM because it has no torque and therefore struggles to spin the motors up fast enough from a slow speed which you sometimes need to stop you smashing into the ground after a low level acro manoeuvre, but at high RPM you don't need the same amount of torque because the motors are already spinning at high speed and already have the required momentum that doesn't require extra torque to get them spinning faster quickly. The higher PWM makes the motors run smoother at those higher RPMs.

I have version 32.8 of BLHELI_32 firmware on my GEPRC Mark4 HD5 quad with a PWM Frequency Low of 24kHz and a PWM Frequency High of 96kHz, and it flies beautifully with no issues. I don't even get the hot motor issue that people have been complaining about with the BLHELI 32.8 "bug".

If however you run BLHELI 32.7 which doesn't have variable PWM and you set the PWM to something high, then yes, you are going to have an unhappy flying experience at low motor RPMs.

As for the "F4" ESCs now on the market, yes, it is because of the shortage of the non-"F" MCUs and the F3 MCUs that are (were) normally used on ESCs. There are no real world benefits of having an F4 MCU over an F3 MCU to run an ESC. So any manufacturers who are trying to sell the "F4" MCU as a benefit on ESCs are just using it as marketing BS. Prices of F4 based ESCs will also be unnecessarily higher due to the higher cost of F4 MCUs for no real benefit to an end user.

Ok… cool … looks like “I learned something today”…
Thanks

We have kinda destroyed the topic but lately we have a few people chasing the Dev's on the variable PWM stuff with the BLHeli_32: https://github.com/bitdump/BLHeli/issues/546

From the developer:

"The way BLHeli_32 currently does variable pwm, is by a linear relationship between throttle and pwm frequency. This has the benefit of increasing motor responsivity, as when throttle is lowered, pwm frequency is lowered, which leads to stronger active braking. But of course this increased responsivity can also lead to unwanted effects, like noise increase or oscillations.
........
We will shortly publish a testcode where we will add the option of letting pwm frequency track motor rpm, in a similar way that AM32 does it. Such a way of controlling pwm frequency will probably generally be more gentle, but also not provide the potential benefit of increased responsivity due to stronger braking."

So hopefully some good stuff coming our way once they fix the variable PWM implementation in BLHeli_32.

As for the ESC of choice based on the lowest or highest PWM frequency it can support, I will not suggest to use this as a deciding factor whether to purchase or not purchase an ESC.

Just buy the best most reliable ESC you can buy today. The bugs will be sorted out eventually.

Worst case you can request the BLHeli_32 devs to provide a half PWM test code for your particular situation such as this example: https://github.com/bitdump/BLHeli/issues/538