Typhon Ideas on whether xlx2 will handle 4s tp motor high kv?? Limited battery space..

[CharlieA]

Working on my stretched typhon. Wish I had more battery space!!!

 

[Dan B.]

Yes, as long as the TP motor is four pole. (36, 40, 42 series, etc.) When you get into their 56 series motors they are 6-pole and you have to keep the KV’s super low. Even then the XLX2’s don’t really seem to like them.
Good looking project, man. Do a build thread!

 

[Diem Turner]

As Mr. B. said, if you're using any of their 4-pole motors (36xx, 40xx, 42xx) you can use any of them as the XLX2 was designed to work with 4-pole motors (all of Castle's own motors are 4-pole).

The ability of the XLX2 to handle 6-pole motors is still a point of debate and, this is my own personal read so take it with a pinch of salt, I think how much KV the ESC can deal with will depend on how many cells you plan on using. If you plan on running a high cell count (6 and up), I'd suggest keeping the KV under 1500. I've seen an XLX2 go up in flames after about 30 seconds run time with a 1920KV on 8S. The contradiction to this generally accepted upper limit is if you plan on running a lower cell count of 3S or 4S where several speed runners have successfully been using a large can 6-pole motor with 2310KV.

Since each build is unique and there are too many other variables that factor into the viability of a ESC/motor combo (i.e. solder joints, connector types, your own particular ESC, wire gauge, etc.) I can't guarantee that such a combo would also work for you so, take it for what you will. Speed running can really tax a system and things can happen that you're just not ready for but...that's part of the deal when pushing the envelope of what these cars can do.

 

[Dan B.]

As Mr. B. said, if you're using any of their 4-pole motors (36xx, 40xx, 42xx) you can use any of them as the XLX2 was designed to work with 4-pole motors (all of Castle's own motors are 4-pole).

The ability of the XLX2 to handle 6-pole motors is still a point of debate and, this is my own personal read so take it with a pinch of salt, I think how much KV the ESC can deal with will depend on how many cells you plan on using. If you plan on running a high cell count (6 and up), I'd suggest keeping the KV under 1500. I've seen an XLX2 go up in flames after about 30 seconds run time with a 1920KV on 8S. The contradiction to this generally accepted upper limit is if you plan on running a lower cell count of 3S or 4S where several speed runners have successfully been using a large can 6-pole motor with 2310KV.

Since each build is unique and there are too many other variables that factor into the viability of a ESC/motor combo (i.e. solder joints, connector types, your own particular ESC, wire gauge, etc.) I can't guarantee that such a combo would also work for you so, take it for what you will. Speed running can really tax a system and things can happen that you're just not ready for but...that's part of the deal when pushing the envelope of what these cars can do.

Any idea if an MMX8S plays nice with a high KV 6-pole?

 

[CharlieA]

Thanks for input y'all. I'm probably wrong but I've always had the assumption that more power and less kv is more efficient with less heat and strain on ESC and from calc seems like more speed but I'm so limited on space I guess I may go to lower voltage to accommodate. My pb as a speed runner is 129. I definitely have a lot to learn.

 

[Diem Turner]

Any idea if an MMX8S plays nice with a high KV 6-pole?

No clue honestly as I've only ever seen people run the 56xx and 58xx motors hooked up to an XLX2. My gut says that the lower amp limit of the MMX8S will be an issue as they do tend to have a relatively high amp draw. That being said, I'd lean towards treating it like an XLX2 in the absence of evidence that it does better. But that's just me.

 

[Dan B.]

Thanks for input y'all. I'm probably wrong but I've always had the assumption that more power and less kv is more efficient with less heat and strain on ESC and from calc seems like more speed but I'm so limited on space I guess I may go to lower voltage to accommodate. My pb as a speed runner is 129. I definitely have a lot to learn.

You’re right, as long as you can gear up as needed. 8s with a low kv motor, geared to the moon, is a pretty popular approach for a lot of speed runners.

No clue honestly as I've only ever seen people run the 56xx and 58xx motors hooked up to an XLX2.

Me too.

My gut says that the lower amp limit of the MMX8S will be an issue as they do tend to have a relatively high amp draw. That being said, I'd lean towards treating it like an XLX2 in the absence of evidence that it does better. But that's just me.

You’re probably right, and after all the time and money that’s going into my next build I do not wish to build a bomb right off the jump. But it begs the OP’s question and I keep wondering too, what ESC’s are people using with all of those big can TP’s? TP keeps building those animal motors, somebody is rocking them…
But yeah, did you see that one video of Shifrin’s where he roasted like three XLX2’s back to back to back on deceleration after his speed runs? Those six poles were back feeding so much power into the ESC’s that it was a very expensive smoke show. Every time!

 

[Diem Turner]

Thanks for input y'all. I'm probably wrong but I've always had the assumption that more power and less kv is more efficient with less heat and strain on ESC and from calc seems like more speed but I'm so limited on space I guess I may go to lower voltage to accommodate. My pb as a speed runner is 129. I definitely have a lot to learn.

There are definitely a lot of variables to consider when making motor choices, several of which will be specific to you, your use case and environment. From my own understanding, it isn't the lower KV that makes it more efficient. It's the higher voltage that you run low KV motors at (I haven't seen any testing that would indicate an advantage for either system and I think it would be exceedingly difficult to do this as even two runs with the exact same setup (gearing, batteries, etc) can produce two very different results so, given this circumstance, I don't see how you could compare two runs with different motors (one high, one low KV with different gearing) and hope to collect any meaningful data on which is more efficient).

You’re right, as long as you can gear up as needed. 8s with a low kv motor, geared to the moon, is a pretty popular approach for a lot of speed runners.

Me too.

You’re probably right, and after all the time and money that’s going into my next build I do not wish to build a bomb right off the jump. But it begs the OP’s question and I keep wondering too, what ESC’s are people using with all of those big can TP’s? TP keeps building those animal motors, somebody is rocking them…
But yeah, did you see that one video of Shifrin’s where he roasted like three XLX2’s back to back to back on deceleration after his speed runs? Those six poles were back feeding so much power into the ESC’s that it was a very expensive smoke show. Every time!

Yeah. I don't have his kind of money to burn so I'm going to play it (relatively) safe.

 

[CharlieA]

I think higher voltage is definitely the way to go as when I compare the same motor and input each kv low to high the speed increases using the same voltage for different cell counts using the same gearing. The same motor of different kv's are going to produce the same power out but the higher voltage motor is going to be faster because it's going to turn more rpm's

 

[Diem Turner]

I think higher voltage is definitely the way to go as when I compare the same motor and input each kv low to high the speed increases using the same voltage for different cell counts using the same gearing. The same motor of different kv's are going to produce the same power out but the higher voltage motor is going to be faster because it's going to turn more rpm's

Sure, but there are many ways to skin a cat and a lot of the choices will depend on your specific car in your specific location. Not to get too pedantic but, technically speaking the KV value of a motor has nothing to do with how much power (measured in watts which is the product of current x voltage) it consumes, the motor is the consumer in this system and doesn't actually produce any power. It takes the power stored in the lipos and converts it to linear or rotary force (torque). And the last point you have backwards. A higher voltage motor is going to have lower KV values and motors designed for lower voltages are going to have more KV so that, when being operated at the intended voltage both motors will be turning at roughly the same rate (assuming that, other than the number of windings and gauge of the wire, the two motors are the same size and constructed the same way).

If you like, we have threads on here for both 3S and 4S speed run challenges (there's no prize or anything, it's just for the glory. Beyond that, there's a ton of great info pertaining to all aspects of speed running. Due to inclement weather, there won't be that much happening atm but, if you like, come join the fun. The lower voltages are great for learning how to get the car set up properly and helps to keep the car in one piece.

https://www.arrmaforum.com/threads/arrma-forum-3s-speed-run-challenge.52860/

https://www.arrmaforum.com/threads/arrma-forum-4s-speed-run-challenge.55194/

 

[CharlieA]

You're exactly right! Thanks brother

 

[LibertyMKiii]

Any idea if an MMX8S plays nice with a high KV 6-pole?

It has the same motor control / phase logic so it will have the same issue.

 

[LibertyMKiii]

Working on my stretched typhon. Wish I had more battery space!!!

View attachment 343789

View attachment 343790

How high of a KV are you thinking? Heat can become a serious problem if you go too high...

 

[CharlieA]

I'm probably going to go with tp. Do you know if a two pole motor like an scm will generate less heat than a 4 pole? I like the svm motors but am ignorant to whether esc can handle maybe the 3600kv 4s 4080?
Do you mind if I ask how you would run your diffs in a V2 limitless I'm running 2.8 gearing. I have lockers in my limitless and don't know for sure if they are necessary for this typhon build

 

[LibertyMKiii]

I'm probably going to go with tp. Do you know if a two pole motor like an scm will generate less heat than a 4 pole? I like the svm motors but am ignorant to whether esc can handle maybe the 3600kv 4s 4080?
Do you mind if I ask how you would run your diffs in a V2 limitless I'm running 2.8 gearing. I have lockers in my limitless and don't know for sure if they are necessary for this typhon build

I run open diffs on 1/7 scale. Never even change the diff fluid from stock.
SCM 2 pole motors have less torque. I would stay away from those and stick with the 4 pole motors. My recommendation is the CM or SVM series as they handle higher rpms more safely with the metal cased rotor.

3600kv should be good for 4s.
I had been 146mph on 4s with a single TP4070 CM. I'd imagine you can go pretty fast with dual 4080s.

 

[CharlieA]

Awesome! That's pretty fast with a single 4070. I smoked a MMX8S with my 4050cm 3200kv in my typhon before I switched chassis. Think I had it over geared and only got 115mph didn't hurt the motor though

 

[LibertyMKiii]

Awesome! That's pretty fast with a single 4070. I smoked a MMX8S with my 4050cm 3200kv in my typhon before I switched chassis. Think I had it over geared and only got 115mph didn't hurt the motor though

Yeah the key is to slowly progress and start with a mild gear setup.
I'd be happy to help you review logs along the way and teach you what the logs are telling you.

 

[CharlieA]

Sounds good. I have a 2028 1700 in my limitless. Switched gearing to 35p/40s haven't got to run it but that's the smallest I could get to reach with rotolock mount running onyx8000 and I do have lockers with 2.8 diffs. Still had problems setup my steering. Got a betu 55kg high speed torque servo but it seems jerky a little. Might have to switch to something else maybe pp if I can afford it. When I get a run that's worth logging id appreciate your input

 

[SrC]

As Mr. B. said, if you're using any of their 4-pole motors (36xx, 40xx, 42xx) you can use any of them as the XLX2 was designed to work with 4-pole motors (all of Castle's own motors are 4-pole).

The ability of the XLX2 to handle 6-pole motors is still a point of debate and, this is my own personal read so take it with a pinch of salt, I think how much KV the ESC can deal with will depend on how many cells you plan on using. If you plan on running a high cell count (6 and up), I'd suggest keeping the KV under 1500. I've seen an XLX2 go up in flames after about 30 seconds run time with a 1920KV on 8S. The contradiction to this generally accepted upper limit is if you plan on running a lower cell count of 3S or 4S where several speed runners have successfully been using a large can 6-pole motor with 2310KV.

Since each build is unique and there are too many other variables that factor into the viability of a ESC/motor combo (i.e. solder joints, connector types, your own particular ESC, wire gauge, etc.) I can't guarantee that such a combo would also work for you so, take it for what you will. Speed running can really tax a system and things can happen that you're just not ready for but...that's part of the deal when pushing the envelope of what these cars can do.

I would add, that the type of wind also influences this. D vs. Y type winds.

 

[LibertyMKiii]

Sounds good. I have a 2028 1700 in my limitless. Switched gearing to 35p/40s haven't got to run it but that's the smallest I could get to reach with rotolock mount running onyx8000 and I do have lockers with 2.8 diffs. Still had problems setup my steering. Got a betu 55kg high speed torque servo but it seems jerky a little. Might have to switch to something else maybe pp if I can afford it. When I get a run that's worth logging id appreciate your input

The onyx 8k packs are what I was using for my runs. I only ever made 2 passes on 4s. The very first pass was 142 mph. I geared up and then ran 146 mph. The setup had much more speed in it but I started to have range issues. (The only reason I started this aggressively is that I already maxed out the car on 2s and 3s and had a strong knowledge of what to expect on 4s)

All the big name guys of speed running tried the lockers and didn't like the handling. You have to have a really really really smooth road for it to not be jerky with a spool.
I think spools are just not worth it except for maybe use in Drag racing applications.

This is why I run normal diff fluid in my 1/7 scale cars.