Motor guru, explaining why 2700kv+ motors will kill XL X

btosic

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So, some time ago I wrote about my experiences with high kv 6S motors killing XL Xs, without known reason(to me). This was posted today, and this guy knows his thing. He explained why 2700kv+ motors will kill ESC on 6S no matter which. First 10 minutes are for us, car guys, after that is good, but more FPV flying.

 

fpvmiller

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Not surprised. All my drones are low kv high cell flyers. My highest kv motor for my 6s rigs is 1900kv but that's on a 5 inch prop. They get lower with my bigger props. The higher kv and the higher cell count increases the rpm and in turn your amperage and yeah your esc won't be happy. I'm surprised the surface guys haven't been applying this concept.
 

btosic

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Not surprised. All my drones are low kv high cell flyers. My highest kv motor for my 6s rigs is 1900kv but that's on a 5 inch prop. They get lower with my bigger props. The higher kv and the higher cell count increases the rpm and in turn your amperage and yeah your esc won't be happy. I'm surprised the surface guys haven't been applying this concept.
Absolutely agree. I followed the practice until 2019, my bashers are 6-8S 1520kv, and my speed runners are 2200kv 6S(occasionally8S) and I had zero problems for hundreds of packs. But then some people introduced 6S high KV motors for drag and speed run, and many people, including me, go for new motors. My balance is 2 XL X killed in same manner. No heat, no ripple, no voltage drops(big enough) , but they went... CC inspected ESC and couldn't find the problem. After all, I went back to 2200kv 4070CM, which is high too, but no problems anymore.
It is important to me to be honest and to share all info I gathered, because I like to know cause and to understand it.
 

LibertyMKiii

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So, some time ago I wrote about my experiences with high kv 6S motors killing XL Xs, without known reason(to me). This was posted today, and this guy knows his thing. He explained why 2700kv+ motors will kill ESC on 6S no matter which. First 10 minutes are for us, car guys, after that is good, but more FPV flying.

I think much of this content is FPV as you said. These are definitely FPV guys. We don't spin our motors at 60k plus rpms. (hopefully)
No doubt about it higher KV pulls more amps. Everything I have seen tells me there is little reason to go above 2200kv unless you want to run on 3s or 4s.

I had run a 5700kv TP Power on 4s and it was a freak! But that was also a very light weight 1/10 scale car. I'd never consider such a motor for an Arrma. The BLX 2050 or a TP Power in the 1700-2200kv range is ideal for the Typhons and Limitless/infraction.
 

fpvmiller

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To mirror @LibertyMKiii

My truggified typhon 6s that is only run on 4s is using a 2150kv motor.

My kraton6s and infraction are using 1700kv motors on 6s.

Plenty happy with them. Balanced between speed and acceleration so great bashers. My limitless build is in the air.
 

btosic

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I think much of this content is FPV as you said. These are definitely FPV guys. We don't spin our motors at 60k plus rpms. (hopefully)
No doubt about it higher KV pulls more amps. Everything I have seen tells me there is little reason to go above 2200kv unless you want to run on 3s or 4s.

I had run a 5700kv TP Power on 4s and it was a freak! But that was also a very light weight 1/10 scale car. I'd never consider such a motor for an Arrma. The BLX 2050 or a TP Power in the 1700-2200kv range is ideal for the Typhons and Limitless/infraction.
Just, to mention one more time, I use 2200kv TP 4070cm on 6S , with no problems, my intention was in past threads I started and in this one, to inform other people, so they won't burn USD 500 in ESCs, as there are "6S 2700kv and 2900kv" motors advertised in this moment. Nothing else.
 

LibertyMKiii

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Just, to mention one more time, I use 2200kv TP 4070cm on 6S , with no problems, my intention was in past threads I started and in this one, to inform other people, so they won't burn USD 500 in ESCs, as there are "6S 2700kv and 2900kv" motors advertised in this moment. Nothing else.

I agree saving people from costly mistakes is always a good thing. I had seen many people doing it so I am glad to learn this from you...

The TP Motor company rates their motors based on what RPMs the motor can handle. 6s (25.2v * 2700 = 68,040) I believe they rate the CM Motors up to 75k rpms. It simply isn't worth it and these 40mm motors perform best between 30k - 55k rpms. There is no need for that much KV and the extra amps they pull.
 

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Higher voltage is always better and more efficient with lower kv. a 2700kv on 6s can and will work fine if the user knows what they are doing. Ive seen people run them with great results. Im prefer high kv motors on my 1/10 speed cars.
 

btosic

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Higher voltage is always better and more efficient with lower kv. a 2700kv on 6s can and will work fine if the user knows what they are doing. Ive seen people run them with great results. Im prefer high kv motors on my 1/10 speed cars.
Looking your videos, I made a decision and went for 8S setup for my speed run car. After that, again, following your advice I kept my 2200kv motor(that I thought it's to high kv for 8S) and all i can say is one more thank you!
 
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