MMM availibility date dropped!

[Sower]

Originally Posted by johnrobholmes

So I assume you are on the design team and have seen the efficiency curves then huh? So much speculation here when in fact NONE of us know jack about the motor other than KV. Knowing Castle's track record, I seriously doubt they would suggest 6s on a motor unless it runs good. If the efficiency suffers, then it will show up as extra heat when the rig is geared for the same final speed.

Well, no, ofcourse I'm not on the design team. And I'll admit I'm no engineer on this stuff so I could be wrong here.

All I know is that if I run this 2200kv motor on 6s it will just have too high a top speed - even if I run a 9t pinion which is the smallest you can get. Under that condition I would be hitting 60+mph. So . . . to make a long story longer, it's just not my choice since I already have my 6s battery and plan on staying with it.

My understanding was that the higher voltage meant better efficiency from lower amp draw.

[Sower]

Oh, one more thing guys . . . my comments about efficiency are also geared towards racing. Like I said, the 2200 motor on 6s has a crazy top end even with the lowest gearing - not the most efficient for racing. That's all, just my $.02.

[SpEEdyBL]

Originally Posted by Sower

The only thing I can say here is that the intention for most people to go with the 6s vs 4s isn't the "more power" argument as much as efficiency. By reducing the amp draw with higher voltage things just run better. I have no problem with the 2200 motor except on 6s. Some people may be fine with it, but I feel it's outside the motor's ideal efficiency. Especially if you're looking to race. Otherwise I'm sure you could have a lot of fun with it. I mean heck, who wouldn't think it's cool to see a 1/8 truggy blasting by you at 70mph?

Like I said, the neu motors are efficient enough that you dont need to worry about running it in their "efficiency range." That was only true for feigao motors. At most power levels you don't need 6s to still have a very efficient setup. The mmm will still handle the amp draw of a powerful 4s setup (btw if the mmm can handle its own motor on 6s, it definately can handle same motor on 4s). That said, I don't see why people would have any problems running the 2200 on 4s for racing. As motors and escs advance, the benefit of running 6s vs 4s at a given power level becomes less and less, especially when the amp rates are well within the escs range. Although power loss is rI^2, the resistance of the motor increases by the square as kv increases. So a 1515 1.5y on 6s is theoretically going to create the same amount of heat as a 1515 1y on 4s at the same power level, because the 1.5y has 2.25 times the resistance.

Benefits of running 4s vs 6s are:

1. Bigger lipo cells holder ther voltage better C wise. So a 6000 mah 4s pack made up of 6000 mah cells is going to hold a higher voltage per cell at 60 amps than a 4000 mah 6s pack at 40 amps.

2. There is less of a possibility for one cell to go below the safe voltage in a 4s pack than in a 6s pack, unless you moniter each cell individually (most cutoffs dont).

In the end, you really do only need 6s for power. Is it better to have two motors or two packs? You can charge one while running the other if you do have two packs. I can only see the 1515 1.5 being absolutely necessary if the 1y is already too much on 4s.

[Just go Play]

Up front I admit to being somewhat clueless about the detailed workings of electric motors so please excuse me if I'm missing something.

Originally Posted by SpEEdyBL

Although power loss is rI^2, the resistance of the motor increases by the square as kv increases. So a 1515 1.5y on 6s is theoretically going to create the same amount of heat as a 1515 1y on 4s at the same power level, because the 1.5y has 2.25 times the resistance.

The spec sheet that I have for Neu 1515 motors shows the 1Y rated at 110 max amps with an internal resistance of .006 while the 1.5Y is rated 70 max amps and .011 internal resistance. This equates to the 1.5Y having 1.83 times the resistance of the 1Y.

Based on the spec sheet the 1.5Y would have a power loss of 53.9 and the 1Y 72.6. While they are close the 1.5Y appears to be noticeably more efficient. Like I mentioned it is entirely possible that there are other considerations that make this not as simple as I think it is.

Originally Posted by SpEEdyBL

Benefits of running 4s vs 6s are:

1. Bigger lipo cells holder ther voltage better C wise. So a 6000 mah 4s pack made up of 6000 mah cells is going to hold a higher voltage per cell at 60 amps than a 4000 mah 6s pack at 40 amps.

Based on user experience this sounds right but I cannot find any reliable documentation that proves it. (for that matter who has 6000mAh cells available today?) The discharge graphs proved by many pack builders seem rather questionable if there are any available at all. Whats worse is that there does not seem to be any standards when it comes to testing or rating lipo cells from one brand to another. Could you point me to any reliable data on cell discharge rates that confirms this claim?

Originally Posted by SpEEdyBL

In the end, you really do only need 6s for power. Is it better to have two motors or two packs? You can charge one while running the other if you do have two packs. I can only see the 1515 1.5 being absolutely necessary if the 1y is already too much on 4s.

I really don't think that this is a valid argument. Both motors are capable of creating almost the same amount of power at simular RPM's. I also don't think that anyone can reasonably argue that low voltage high current is more efficient than high voltage low current setups. If this was the case then everyone would be building rc's with ultra high kv motors to run on 7.4v packs right?

[SpEEdyBL]

Originally Posted by Just go Play

The spec sheet that I have for Neu 1515 motors shows the 1Y rated at 110 max amps with an internal resistance of .006 while the 1.5Y is rated 70 max amps and .011 internal resistance. This equates to the 1.5Y having 1.83 times the resistance of the 1Y.

Based on the spec sheet the 1.5Y would have a power loss of 53.9 and the 1Y 72.6. While they are close the 1.5Y appears to be noticeably more efficient. Like I mentioned it is entirely possible that there are other considerations that make this not as simple as I think it is.[/COLOR]



Based on user experience this sounds right but I cannot find any reliable documentation that proves it. (for that matter who has 6000mAh cells available today?) The discharge graphs proved by many pack builders seem rather questionable if there are any available at all. Whats worse is that there does not seem to be any standards when it comes to testing or rating lipo cells from one brand to another. Could you point me to any reliable data on cell discharge rates that confirms this claim?



I really don't think that this is a valid argument. Both motors are capable of creating almost the same amount of power at simular RPM's. I also don't think that anyone can reasonably argue that low voltage high current is more efficient than high voltage low current setups. If this was the case then everyone would be building rc's with ultra high kv motors to run on 7.4v packs right?

To answer your questions:

1. From those specs it looks like the the 1.5y isn't ideally 1.5 turns in comparison to the 1y. An ideal 1.5 turn would have wire that is 1.5 times the length has a 1 turn and 2/3 the cross sectional area (to fit in the same space), making it have 1.5 x 1.5 = 2.25 times the resistance and 2/3 the kv. That said, the motors cannot be considered "equivalent" with the 1y on 4s and the 1.5y on 6s.

2. http://www.enerland.com/product/p1.php?num1=1&num2=4 These are considered to be some of the best cells in the industry. It's quite obvious that bigger cells hold their voltage better under a load than smaller cells when you look at the discharge curves. True that there seem to be no 6000 cells available, but that has nothing to do with my point. I was comparing 4000 mah cells to 6000 mah cells for the sake of simplicity.

3. I never said that lower voltage was more efficient than high voltage. In fact i never even said they were equal in reality. I said that a neu 1y on 4s is efficient enough for it not be necessary to use a slower motor on 6s. So how can a 4s setup that a.) that still runs cool and b.) has all the power you need, be inadaquate?

[DrKnow65]

No "for sure" awnsers from me JGP, but I am impressed with your posting skills :)

I believe the consideration for me (aside from all numbers) is the idea that 2200kv motor is a good base for 4S-6S systems. I agree the rpm's are high for 6S but the ideal KV motor for 6S would not perform as well at 4S. I personally would rather have an overkill on 6S than an underkill at 4S.

Would be good day to have one guy with access to EVERY lipo cell out there test them all in one particular way and post the results for the world to see. What that one particular way is, can be disputed. Let alone the idea of one guy having all the lipo's to test. Same thing for all the brushless motors.

[cart213]

I'll volunteer to do all the testing if y'all will fund my paypal account so that I can buy one of everthing!

[johnrobholmes]

Efficiency and amp draw are not tied together directly. Amp draw creates heat with resistance, but higher wind (higher voltage) motors also have more resistance to go along with the reduced amp draw. So, without dyno graphs and specs of a specific motor the ideal voltage and KV cannot be determined for a particular situation.

Of course buying more batteries is an inconvenience. So is buying a new motor and ESC. I would prefer a wind that was great on 6s and outrageous on 8s for battery amp draw reasons. The MMM is a 6s controller so a 4s mild, 6s wild motor just makes sense for the first release.

[glassdoctor]

I really don't want to talk motor theory, but keep this in mind when studying motor specs... on the Neu site I think the amp draw specs are max amps at the max rated voltage. The watts should be basicly equal on all winds. Lower kv motors will naturally have an efficiency advantage due to the lower currents they use to make the same horsepower.

[ssspconcepts]

Sure I'd like to see more CC MMM motors offered....but the fact that they are only going to initially offer a 2200kv motor is not going to sway me (or other enthusiasts) one way or another. Neu 1515 motors are "cheap" right now...$245 on Neu's website! These are proven motors and that's some of the best pricing I've seen in a while. The way I see it is that if folks want more selection in kv, they will buy it directly from Neu. After all, we always have in the past...why should anything change now? The "genuine" Neu motors (not the CC version) are certain to still be better in terms of quality...which is what I use as a guiding principle for most of my purchases. If I am building a special rig or if I have a special application, then I will still probably go with a Neu.

I am not going to sit here and beat up CC for not offering more kv motor selections. I can control that myself by purchasing the very best motor money can buy from Neu. However, what I will beat up CC for, is not cowboying up and getting the MMM product to market before the foreign competition got theirs out on the street. But its not just CC...there are others that in my view that are also guilty and have been asleep at the wheel. I have to tell you...the expectation is pretty high at this point and time for the U.S. market to come up with something truly spectacular...namely a HV ESC that blows the competition away.

[lutach]

Originally Posted by ssspconcepts

I have to tell you...the expectation is pretty high at this point and time for the U.S. market to come up with something truly spectacular...namely a HV ESC that blows the competition away.

I think an HV MMM would've been the perfect controller. Like I said before, have it handle up to 12S lipos and I know a controller that handle 12S can also handle 6S. Then the choice for a motor would've been huge. Just picture a Mega ACn22/50/2E running 12S of the little 2200 or 2500mAh cells. A few guys would probably a Plettenberg Bolido n a 5th scale. It's funny how Schulze has a huge array of controller and Castle has the ability to do that, but they are lacking behind. Yes, Castle has better programming and awesome features in the controllers they make, but where is the HV version for vehicles?

[Cain]

I personally am excited for the ESC. I run 4S right now and won't be doing more than that, so I am not too concerned. Main thing I am looking forward to is the fact that I don't need all the fans, and external UBEC like before.

[pipeous]

I am with you on that one Cain. I can use my MM in something else and just grab the mmm esc for my 4s buggy, and then a combo for truggy.

[DrKnow65]

Would there be an issue if the MMM/2200KV had torque and rpm limiting software?

[strodedawg]

i understand that using a higher voltage lipo yields less amp draw, which yields lower temperatures. what i am cofused on is that i can use a lower C rating and less mah and still get the same run time?
any info would help
can't wait for the mmm