But did you deeply understand the math or just got the main point of the video?

@@the_letti0584 I wouldn't say "deeply" understand since this was a short video lol, but I did comprehend the formulas he showed. Which lead me to watch even more videos on just that alone and have a pretty good understanding now. I already knew the basic principle behind the main purpose of this video but didn't know why. Now I do

Seems like you know a lot about this topic so you may be able to help me: twice the kv doesnt just give 4 times more torque but consumes for times more amperes, right?

@@the_letti0584 no

That would be truly awesome

Glad you enjoyed it!

just go 3s, it will be perfect!

Not a good idea in a crawler, will smoke the esc. Use 100% epa and gear down instead.

@@HolmesHobbies yes sir

Indeed, there are limits on gear ratio

You can use reducer for example 3:1 or 5:1 and change the spur and pinion to hit the ratio you want

@@helmydewa yes you can do that. There is a lot you can do, but it is a lot easier to pick the right KV engine that suits your vehicle and how you want to drive it 🙂 Then if you are not happy with it, you could do what you mentioned 👍🙂

True that more turns provide more torque per amp. The issue is that it will lose amps per volt "faster" when increasing the number of turns. Thus less torque per volt when increasing the turns. If one stick to the same volts per turn the motor will theoretically behave the same, no matter if it's one or a hundred turns...

Depends on how you drive. If super easy, runtime will be about the same. If you drive hard, the higher kv will have less time because you are using the extra power available. Longest runtime would be 1000kv at 40:1 however. But wheelspeed is half as much.

Just a reminder: using a 3600kv compared to using a 1800kv motor will divide your runtime by 4! Just make sure it’s worth it

We don't always neeeed the extra torque...

It works on brushed until about 21t550 or 27t 540, then brush saturation makes them lose torque

@@HolmesHobbies nice info, thank you

I'd just run it on 4s, but going to a 11 to 13t pinion isn't a bad idea

@@johnrobholmes gotcha I know you recconmend 6:1 gear ratio for crawling just didn't know how the portals effect that ratio.

I dont know what the exact terms you are asking about mean in relationship to the gear ratio (wether undergearing means too high or too low gearing) but i may still be able to answer your question… Anyway: having too high gear ratio e.g. 400:1 basically means that your car isn’t driving as fast as you’d like it to (for example a crawler you want to go on walks with should be at least as fast as you walk). This will give you way more torque compared to normal gearing and affect the esc in no negative ways. On the other hand a gear ratio of 5:1 will make your car go crazy fast while taking away a lot of torque and heating up the esc more (shouldnt be a problem in crawlers but fast cars may turn off their esc when it gets too hot). Having too low gear ratio puts the motor under a bit more pressure but a good motor shouldnt take any damage from that. If you have any questions on what gearing to use in order to get the right speed for your vehicle go ahead and ask

I might have already filmed this...

This was just a thought experiment to show that lower kv does not produce more torque in most situations

Same runtime unless you use the extra torque available. Driving style and terrain unchanged, same runtime

@@johnrobholmes your left finger on the radio doesnt directly control the torque but the wheel speed. A 3600kv motor will deliver 4 times more torque while consuming 4 times more electric energy(= solid number of voltes multiplied by he amount of amperes). If we’re not taking in count that you might have to give more throttle with the lower kv motor to reach the necessary torque to conquer the obstacle it‘s clear to say that the higher kv motor consumes 4 times as much energy so your runtime will drop from 1 hour to 1/4 hour aka 15 minutes. Idk how a 1800kv brushless or a 3600kv brushless motor actually runs in crawlers (ive only used brushless in my faster cars) but if the 1800kv performs at least as well as brushed stock crawler motors i can recommend to use a 1800kv motor for trail or scale crawling. If you’re more into extreme rock crawling the 1800kv will do it aswell but the 3600kv will do it way more smoothly (while dividing your runtime by 4). The only reason i see for upgrading to a high kv motor in crawlers are competition crawlers (or just wanting to keep your throttle finger at the same spot while climbing extreme obstacles). As I’ve said: idk how much torque a 1800 brushless motor delivers but in every phrase i wrote i was just expecting it to deliver at least as much torque as the cheap stock motors

@@the_letti0584 watts are watts and the battery isnt changing. At 4mph both rigs use the same energy, more or less. It isn't until loading down that the faster motor can pull more torque. So, Unless you go binding the rig down harder, the faster motor with more gear down does not affect runtime very much.

Runtime is not affected much unless you bind it down more and use the available torque. On the average, I do not lose much runtime besides what a twitchy finger and sometimes harder acceleration cause. Now, if we threw in the faster motor without regear the runtime would go down a lot. More wheelspeed? Always less runtime.

@@johnrobholmes is it because if you geardown more, the motor spins not hard as the other one with higher gear ratio isn't it...?

Practically identical

It would be easier to control (slower always is) , but not necessarily slower startup.

We have to keep something constant for sake of comparison. If we doubled the voltage for the slower motor and didn't change gearing, the example would basically be "how much voltage drop in your esc assuming it can handle twice the voltage" and nothing more. Since most escs are ran near their voltage rating, it's not a useful demonstration to showcase that lower kv motors don't actually produce more torque.

@@HolmesHobbies Doesn't necessarily have to be double, and my proposal in general is more for people looking to either select their power system from scratch, or start over completely.

Brushless

There is a point where more wheelspeed or more gear down isn't wanted or possible

Someone would choose to run a lower kv motor cause (ratio between different kv-motors) squared is the factor for extra energy comsumption… as showm in the video: ratio between 3600kv/1800kv=2. 2 squared=4. if you look closely into the data about i (which is the amount of amperes) you can see exactly what ive written and he also explained why you have to calculate just how ive shown you (because of heat creation inside the motor…) This basically means that twice the kv gives you 4 times more torque and divides your runtime by 4.

In brushed, going faster than what i offer does actually harm torque . I'll have to make a vid on it. I brushless, over 3500kv becomes hard to gear down enough for and the esc/ battery take more beating.

bill, bill, bill, bill...

Could explode the rotor if it's really fast. My motors are 60k no load rated. Still not a good idea to Rev them without load

Like weed-high??

There are limits with the battery, esc, and wires that give us a goldilocks zone around 2700kv on 4s and 3500kv on 3s.

Haha, in germany (maybe even all over europe) it isnst V aswell but it’s U. Of course V is used for volts but in calculations we always use U

What happened when you introduce sensored vs. nonsensorred brushless systems into the equation?

for brushed and brushless it works similar. volt up = higher rpm. higher rpm = higher wheel speed. gearing down = lower wheel speed and higher torque.

@@mrstanton81 sensored and nonsensorred only means the quality of controlling of motor rotations. it is important on slow rpm's.

With brushed, it's true down to about 30t to 27t range. Then, as it gets slower it loses torque again. All due to brush saturation vs coil resistance.

There's a lot of misconceptions with electronics in general. One can only do so much to educate!