Excellent info as always!! These are important things to know in a world where bigger is always looked at as better ! You were the one to explain amps to me as well, another important factor 😵 You're explanations are simple and clear and very helpful. Looking forward to every vid !
lower volt setup gearing becomes more critical because lower voltage systems will draw more amps if the load demands it ? So I might as well go with a larger physical size motor to negate the heat right ? a larger motor will give more tq too.
So in other words what I gather is that higher voltage system draws less amperage than lower voltage high kv setups to get the same job done. less amperage draw, low kv high voltage = longer runtime compared to high kv low voltage setups which drain batteries in the wink of an eye
Yes, that is correct. When considering longer run times with higher voltages this is only true if the setup is more efficient. You may not even notice the difference in efficiency. Going with a high voltage setup is not always possible or practical. I would say if you are planning to pull 125-150A or more, (continuous) try and consider a higher voltage setup if possible. If you haven't already seen this video, take a look: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-x44GB5zbOSI.html
The best Kv is one that allows you to operate at the voltage you are using and the gearing that the Kraton has. If you are looking for more speed, you want to increase the amount of power that you can deliver. This generally means using a larger motor to draw more current or using more voltage.
All well and good Except - - - - - Lets assume that you (Mr. RCExplained) are going to look at my (Mr. Guesser) RC car and there will be sufficient information to tell you the axle gear ratio, the Motor Drive Gearbox Ratio, the weight of the car and battery is known, and the battery will be a reliable 2s brand. Aside from experimentation - how are you going to determine the KV that I want for my vehicle. Some car kits specify the motor size and the KV, but that doesn't mean it's right. I've purchased kits that the motors ran so hot on that they kicked out the safety on the ESC, and I've purchased kits that were so underpowered that I just had to run out and buy something with better performance. The only way I can determine when I've reached peak performance is put the motor in and gear it up or down until it's running an entire battery without getting hot. I look at the motor specs and see it's 5000kv, but then I go to the motor store, and I see a motor with the same specs, but a vented can and of course another motor with higher KV with vented can, and start the guessing game again. Unless you can plug all of the information you present into a program and every manufacturer gives reliable KV information, it's still a guessing game.
Hi Larry, thank you for your comment. Picking a power system for an RC application is not the easiest thing in the world, nor is it a very well defined process. This is the basis for this channel, to shed some light on these challenges for the hobby. I hope the collection of videos provide insight to make this process more simple, promote an awesome hobby and bring on new enthusiasts. If you haven't already, check out the video that is a lot more specific to picking out a power system as this particular video only talks about the reasoning why there is a list of kv options provided to us by the manufacturer: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-UdvZvySOHW8.html and another that is more specific to a 1/8 scale buggy: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-trt75YsMipU.html I do see the point that you are driving at. However, I don't treat the process as a guessing game. There is a lot that you can do to figure out what kv you require for your application and also the size of the motor. As you allude to there is also a much needed tolerance on the kv that you select. You must be able to vary your load between a min/max range otherwise you have a problem. (Manufacturers Tolerances e.g. a 5000kv motor is rarely a true 5000kv motor [did a video on this] / same idea would apply to a 50C battery pack - a change in environment / conditions --> more variation) Dialing in your setup will absolutely be necessary and is the final step in the process.
I ended up getting a 2400kv motor for my 1/8 buggy with an xr8 plus 150 amp esc. Also 120c protek batteries. I did not build the kit yet, but i feel i should have went with a 1900kv motor. If i just gear down, would I be okay? Would 14-46 gearing be ok? Would I still have the torque of the guys running say, 1900kv motors and 18t pinions. Thanks in advance.
Hi Nick, without knowing your exact setup, using 4s on a 1/8 scale buggy with a motor kv of 2400 is a pretty typical setup. You should be able to keep up with the guys running 1900kv equal size motors on 4s. You won't keep up with the guys running 6s.
Yes it's also very complex depending on the application. Primary reason for the complexity is being able to calculate the load. This makes it unpractical. It's far easier to compare against known data.
