Which brushless setup for under $170?

[timie1]

Ok people. I have searched and searched for the answer to my questions, but as helpful as you brushless users are, no one seems to have asked this question.

I have a B4 and a set of pinions from 18-29 with a 79 and 81 tooth spurs. I have a GP3300 and IB3800 and a Sanyo nicad, all with deans connectors.
I run mainly onroad lately and I don't want to have to buy anything else like more pinions or batteries at this stage.
I want a brushless setup that will be fast, AT LEAST 35mph but not insane speeds like 60mph. I don't want to ruin my drivetrain so I don't want super insane lipo speeds. It has to be driveable at low speeds, with no cogging preferably. Obviously the cooler it runs the better, because in the B4 there is not much airflow around the ESC.
I would like to spend around the US$170 price range. Basically I want brushless cos it's virtually maintenance free and I think even a slower "cheap" brushless setup would be faster than my 19t brushed setup, which I can get up to about 35mph.

The ones I am considering at this stage are:
MM 4600 or 5700
Novak XBR sport 8.5
Traxxas Velineon

I would "prefer" the novak because I think they are superior in build quality and less chance of cogging, but with my batts and equipment and desires, maybe cogging wouldn't be an issue.
I like the VXL cos it (on paper) runs both sensored and sensorless.
Wouldn't the MM esc run a novak or LRP sensored motor on a sensorless mode by not plugging in the sensor wire? The orion motor works on sensored and sensorless esc's, so perhaps ALL brushless motors and esc's would function the same way.
Bear in mind, I have no plans to go lipo, or even 7 cells. Just an old skool 6cell 7.2V battery.

So, to re-iterate, I want driveability, without the issues of cogging, over heating, thermalling esc, and having to buy lipos or drivetrain parts constantly. I want something that will last a long time with no real maintenance to speak of, and I would like it under $170.

I'm open to suggestions of other makers.

So please everyone, tell me your thoughts.:D

Thanks

[chilledoutuk]

for 6 cells i think either the mm 4600 or if you want more power the 5700.

The velineon is a good system but not a versatile as the mamba max.

[viper7016]

For 6cell Nimh packs and no cogging your only real answer is the Novak. There is no reason to go with a sensorless system if you don't need high voltage capabilities and crazy speeds.

ANY sensored motor can be run with a sensorless controller, however it doesn't mean it will run well. And certainly don't expect there to be no cogging. As of right now the MM cannot run the Novak motor well enough to waste your time with that combo. They are working on some software that is supposed to make it work better or so I hear.

Novak's build quality and customer service are more than decent. I have had 2 Novak 5800 systems, a GTB 6.5 and I have an XBR 8.5 in the mail right now. I have had no real issues with them and don't expect to.

If you have a lower end radio you will most likely get glitching, don't confuse it with cogging. I will be getting a MX-3 FHSS soon and those days should be over. Some people say they can rearrange their wires or wrap the receiver in foil and various other things to solve the glitching but I have had no luck with that. Maybe its the powerlines or something who knows.

If your air flow to the ESC is really bad I would cut a hole in the body or something, ususally something visually pleasing can be made to work. Heat is bad for any system.

I hope you have fun, I know I will.

[timie1]

Thanks for the quick reply chilledout.
In terms of performance, how would the 4600 with 6 cells go when compared to a decent brushed motor? What about the 5700?
My 19t brushed is a fairly decent motor and it gets along quicker than an only mediocre 15t brushed. Would the slowest brushless be as quick as a decent 15t brushed?
When you say the velineon isn't as versatile as the mamba max, how do you figure that?
This is an exact copy of what the traxxas support guys sent out to me when I asked them how it runs a sensored motor.
"It will handle any 540 size brushless motor. The ESC will handle 200A
constant, and 300A peak. That's more than these motors will pull in a
realistic installation. The esc doesn't care about KV, but the gearing
does- because it can overheat the motor... The esc will handle it if
properly geared and you stay under 200A. This is the smoothest sensorless
ESC I've seen and it works just as well with sensored motors. Novak sensor
leads connect directly to the esc auxiliary port."

From what traxxas say, it seems that it's quite versatile.

[timie1]

Novak's build quality and customer service are more than decent. I have had 2 Novak 5800 systems, a GTB 6.5 and I have an XBR 8.5 in the mail right now. I have had no real issues with them and don't expect to.

If you have a lower end radio you will most likely get glitching, don't confuse it with cogging. I will be getting a MX-3 FHSS soon and those days should be over. Some people say they can rearrange their wires or wrap the receiver in foil and various other things to solve the glitching but I have had no luck with that. Maybe its the powerlines or something who knows.


Yay, another quick reply :D
How different is the XBR 8.5 to the SS5800? Both are the same Kv and 8.5 turns, and apart from the sticker, the motor looks to be the same.

Yes, the radio glitching............that brings up another question.....will you potentially get more glitching with a MM over a novak XBR? How much more glitching can there be over a normal brushed motor?
The only time I have had glitching problems was with my IB3800 matched pack. It turned out my receiver was too close to the battery. So I moved it about 1cm further away and all glitching ceased.
With brushless, could you do the same and hope it reduces glitching? Or is it that it just screws up low end 27mhz AM radios and no matter what you do you'll never stop glitching?

Sorry for the questions, but you know..........:p This is the place to ask them:D:teacher:

[viper7016]

As for the VXL running sensored motors there is a thread about them specifically. I don't know if you've read it. I've only started it so I can't comment. I got to the point where they were talking about a software problem killing sensored motors.

The motor is exactly the same as the SS5800. I don't think you would get any more glitching with the MM than you would with the Novak, but you most likely will get some cogging with it. Whether that bothers you or not is subjective. You can probably move wires and components around to help the glitching, I have just not had any personal success with it. Or didn't care enough.

There is also a sintered rotor kit for the 8.5 so later on down the road you can upgrade that and get a little more torque and efficiency :D

The 5700 in a rustler with 2S lipos will get low to mid 40's with decent gearing. I don't know what you think a decent 15T is but I had a Trinity Speedgems Titanite 15t and the 5800 would slaughter it. I personally think that for a stadium truck the 8.5 with good batteries is all you need to have fun.

[SS Pede]

+1 on the Novak XBR system. My SS5800 is great in my Stampede. With a B4 it should be even better. Runs great on any decent batteries.

[GSMnow]

Just to be different, I will chime in with my 2 cents.

I run a Mamba Max 5700 in my Losi XXX-T. It is FAST!! with power almost matching a good 10/11 turn brush motor. The torque curve is different so it is not a direct comparison. Assuming they were geared for the same top speed of about 40 mph. From a dead stop, the brushed 11 turn probably hits about as hard. At 10 mph, the brush motor might actually be a tick stronger. At 20 mph, the brush motor is tapering off while the Mamba is still pulling harder that from a stop. At 30 mph, there is no comparison, the brush motor is gradually accelerating compared to the MM 5700 still able to pull a wheelie. Torque on the Mamba finally starts to fall off at 35+ as it reaches top speed. At the end of the straight, both motors are going 40. That mid to high range torque is both a blessing and a curse though. Line up for a nice pass, pull a tick too much trigger and you can break the tires loose and spin out. Running a brushed motor at 25 mph, and you can just hammer it in almost any conditions.

I run IB and EP 4200 packs, I have heard bad things about the IB3800 but the 3300's are supposed to be very good. 6 cell only. And I race on a track against very good drivers every week. It comes down to the driver, not the motor. I oil my bearings, the brush guys rebuild each week, we trade TQs and wins. The Novak sensored systems that have showed up here split the difference between the MM and a brush motor. They are smoother at very low rpm, like under 5 mph. They have more upper rpm torque than a brush motor but not quite what the MM can put out for a given wind. The 5700 is about a 7 turn in the Novak world. Far more torque than the 5800 but it has to suck the current to make that torque. So if you have the battery, it can push higher gears for a given KV. With our tight track setup right now, I sorta wish I bought the MM 4600 and I just may get that motor so I can swap up and back for the conditions. I am down to a 15 to 86 ratio now so it tops out at just 33 mph and that is enough to keep up with the nitro guys on this track. Don't be fooled into thinking taller gearing will soften the torque. The Mamba Max has SO MUCH torque that gearing taller just makes it spin the tires up faster so you have to use even less trigger to keep traction. With my current gearing, it runs for over 12 minutes at race pace. In fact, last week, we ran a 7 minute main, and the only electric guy faster than me (10 turn brushed in a 4wd) ended up dumping before the end, so I walked around for the win, and 2 more laps than him. After the race, I ran the same pack for at least 5 more minutes, over 10 laps.

The softer midrange torque of the Novak would probably be easier to push harder on most tracks because of traction limits. I will be trying my MM 5700 in a 4wd. That should be fun.

[timie1]

To GSM....if the Mamba's have so much torque that in an offroad situation you cannot use, then would it be better to get a novak and be able to use a lot more of the power of the motor? If having less current drain for much the same Kv means less torque, but higher runtimes and cooler temps, then perhaps the novak may be better in offroad??
Would the MM 5700 be comparable in overall speed to the Novak 5800 motors? Assuming they are both geared accordingly.

[GSMnow]

I have not done a straight head to head compare, but from what I have seen with my truck and the onroad guys and a 4WD running Novak's. If you geared the MM5700 and the SS5800 the same, yes, the top speed would be close, but the Mamba would have a bit more acceleration available in the mid to top end. The run times would be very close as well. If the track conditions limit you acceleration, then the MM might actually run longer, but if you have the grip and can use the extra torque to accelerate harder, then it will pull the battery down faster. Both systems are very efficient, so the power you get out is taken from the battery, no free lunch. Geared for the same top speed, the run time will be very close. Due to the greater torque capability of the MM 5700 though, most people do gear it higher so it will have higher top end, about the same wheel torque, but a little more current draw for a little less run time.

If you are trying to compare directly to a 15 turn brush motor you will be very surprized. Either brushless system will probably give you (your choice based on gearing) 40% faster top end or 40% longer run time, or somewhere between the two. And they will have more torque at speed.

[ElectricThunder]

A note- the 5800 has a Kv of 5000 (Novak re-rated the motor a little while ago). I've also read that the 5800 is comparable to a 15 turn in an onroad chassis, and maybe a 13 turn in an offroad chassis.

From my experiences, my 5800 was about the same as my P-94 12x2 in a T3 (each motor geared where they ran relatively cool to the touch; "normal gearing" running onroad). Brushed motor technology has improved since then though, and I've also put in a sintered rotor, so it's got more "cojones" than it did when it was the little stocker 5800.:D

[GSMnow]

I did a little test on my MM 5700. I used a fair battery, blocked the truck so the wheels were in the air with the axles fairly straight. Revved it to flat out spinning the entire drivetrain including stadium truck tires. After running for about 2 seconds, it was holding a nice steady note. I measured the battery pack voltage at the ESC input terminals and it was 7.20 on my Fluke 76 meter. I looked at the frequency of the wave on one winding of the motor and it was at 680 HZ. A 2 pole motor has one cycle per revolution so this works out to 680 x 60 = 40,800 rpm.
40,800 / 7.20 = 5,666.67 KV on a motor rated at 5700. And this is spinning the pinion, spur, trans, axles, and tires. I tried loading it a bit, but even with a thick glove, it got very hot before I got much of an RPM drop, and the battery voltage dropped right with it. The only reason the rpm drops with load is because the current increase creates voltage drops in the system. The total drop is from the internal resistance of the battery pack, wiring, FET's, and motor windings. The battery and motor are probably the biggest parts of that. The lower the resistance in the whole system, the closer the motor will hold to the KV rating as it is loaded. And the TRUE KV doea not really change as the "effective" voltage drops making the lower rpm correct for the KV. If the motor RPM falls 570 rpm on my MM 5700, the voltage drop due to the internal resistance is about 0.1 volts.

[timie1]

Wow thanks for all your help guys. GSMnow, you have a lot of cool equipment to test things. I read your other posts and you really get into things :D
By what you people say, a 5800 novak sounds quite good. Certainly quick enough for an offroad B4. If it's equally as quick when geared right as a MM 5700 then it would be enough.

One last question..............running a 6 cell nimh, would I get less cogging on the novak 5800 or the mm 5700?

[viper7016]

I got my Novak 8.5 today, slapped it in my rustler and with my abused and decaying GP3300's my Rustler Fing RIPS. Definitely no need for anything more.

[GSMnow]

Cogging, as most describe it, is a sensorless only issue. The Novak sensored systems should never cog unless something is wrong, like a bad sensor lead or power lead connection. The startup stutter that does sometimes occur on sensorless systems is just the ESC blindly clocking the motor until it finds where the rotor is. The Mamba Max is very good if not great at doing this very seamlessly, but it does sometimes show up. When a sensorless brushless motor is not turning, the ESC has no way of knowing where the north pole of the rotor is pointing. So when you start to pull the trigger, it will just guess and apply power to one winding. There is about a 50-50 chance that it will either pull the motor forward or backward, anywhere from no turn at all to nearly a half turn of the motor shaft. At this point (a small fraction of a second) the ESC still does not know for sure where the rotor is. Based on the amount of throttle you are giving, it will time out if it does not see any back EMF change and so it will clock to the next coil for foward rotation. Again it looks for back EMF, if it does not see any, it continues to clock ahead.
Two things can happen.
1) If the current to the windings is too low to actually turn the motor, it can skip back. This is a worst case, and I have forced my Mamba Max to do it just to see how it handles it. You can force this to hapen by using very light throttle on a steep incline, or by just blocking the wheels. It seems bad a violent but it really is not too big of a deal unless you are nosed against a wall and hammer it. In most cases it is hill induced, and all you need to do is give it more throttle so it increases the current.

2) the current is high enough to turn the motor into the load on it and once it clocks past the current position of the rotor, the rotor will follow the clocking and begin turning. At very low speeds this is OPEN LOOP running. The back EMF off of the windings will still be to low to "tell" the ESC where the rotor is, but the ESC can stay turning the motor like this without a problem if you really need to creep slow. With my MM5700 and current gearing, it stays in open loop clocking to about 1 mph. It is a slow crawl, and if you grab the truck and stop it, you will feel it skip and stutter. That is the so called "cogging" again. As the vehicle picks up speed, there is a point where the back EMF becomes high enough for the ESC to "see" it and use that to determine the timing to switch to the next coil. Again, on my MM5700, you can actually hear the PWM frequency shift and the troque increases and the truck pulls away very smoothly. Once it does this shift, I can then slow back down to a crawl and it stays in feedback "closed loop" running down to a stupidly slow speed.

Some people had a concern that it might stutter and cog at the start of a race and everyone behind would just slam into you on the line. This NEVER happens. A big pull on the trigger puts out alot of current and the motor WILL follow the clocking and take off in a hurry. My bigger concern is too much wheel spin off of the line, cogging is NOT an issue in a race.

The only time I have noticed the sensorless function on track is when I mess up. If you get loose and the vehicle turns greater than 90 degrees from the direction of travel, the rear tires may slow way down, or even turn backwards if you lift off the throttle too much. This causes it to go back to open loop startup mode. To make is as smooth as possible, the current Mamba Max firmware seems to detect reverse rotation of the motor and it only applies braking until the wheels are either stopped or turning very slowly backward. This took me some time to get used to, because I have gotten it out of shape many times before with a brush motor and I was able to give it some trigger and spin the tires forward even though it was still sliding backwards. This is one case where the sensored systems (Novak/LRP) should be able to provide the forward torque even with reverse rotation. The reason for the "sensors" is to tell the ESC exactly where the rotor is so it powers the correct coil. A sensored motor should act just like a brushed motor. The only real difference is the hall sensors tell a bank of mosfets which coil needs current instead of a rotary switch (commutator) directly routing the current to the correct coil.

There are cetainly pros and cons to both sensored and sensorless systems. The older SS5800 that I tried drives just like a good brush motor with a bit more torque at mid to high rpm and greater efficiency. The Mamba Max 5700 pulls about as god as the 5800 from very slow speeds, but then continues to pull harder up to very high rpm, not losing torque until it is almost topped out. Think of it as the ultimate VVTi system as it is dynamically calculating the optimum timing point every rotation. I can't say about the newer Novak/LRP setups, but the SS5800 sure did not seem to advance timing as the rpm climbed like the Mamba Max does. There is no reason a sensored system can't do dynamic timing, it just takes some software code in the ESC to do it. I almost laughed when I started seeing sensored motors with adjustable timing by turning the hall sensors. Talk about acting like a brush motor.... The timing should be able to all be done in software, and the sensors should be at zero timing for easy reversing. Oh wel, off of my soap box. Novaks stuff is easier to drive, The Mamba Max is brutally fast, but requires you to re-learn some driving technique. Since when has too much power been a "problem"? You have to TEACH YOUR TRIGGER FINGER to be delicate and smooth, just like steering inputs. No more aim and yank.

[timie1]

You Rustler definitely does RIP aye:D Rest in Peace poor Rustler;)
I'm glad you let me know. This is the kind of information I wanted.
What motor did you have before in the rustler? Also, what ESC are you running the 8.5 on? The XBR??

[timie1]

To GSMnow
Have you had, or seen, a direct head to head race between two (almost) identical cars and setups with much the same sort of battery where one was with the MM5700 and the other the Novak 5800?

The reason I ask and have my questions is, everyone knows that in 1:1 real life, a faster car doesn't neccessarily win a race. Nascar is rarely won by the quickest car. It's won by the car that is easiest to drive consistently fast laps, and of course the driver oh and reliability.

Some of the quickest cars in real life are blindingly quick down the quarter mile, but on a ractrack they can't get the power down on the road, and so much of the straight line speed is wasted, and so an easier to drive (correctly) but not quite as fast car will win.

Do YOU think this is the case with the MM5700 and the 5800 Novak?

[Helgaiden]

New players in the game, timie...

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXRST1&P=7
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXRST7&P=7
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXRST8&P=7

then later you can upgrade to sintered rotor...which still ends up being than buying the pro version ($40 for the rotor/endbell kit versus nearly $100 more for the pro version).

[timie1]

Thanks Helgaiden. You'll see that I have already listed them in my original post. Those and the Traxxas VXL and Mamba.

I bought the mamba 5700. According to Shawn at Castle, they are working on an esc update to run the Novak series of motors properly in sensorless mode.
The biggest drawback I have with the Novak EX series is that aside from putting a sintered rotor in, there is nothing more you can do to get it quicker than what it is (going with the 8.5). The esc won't handle anything higher than the 8.5. The Mamba on the other hand, will handle anything you can throw at it, all the way upto 12 cells.

[john91374]

Timie - This is just my opinion and experience. I have run a bunch of Novak and mamba systems as well as a few of the other well know motors and recently the new traxxas "V" systems. I've always had very good reliability with the Mamba systems with zero failures in almost two years. I've killed too many Novak motors and contollers to count. Maybe 5 or 6 of each. The Mamba's always had better accelleration and top speed when compared to equal system from Novak. What Novak did have was better control on smaller tighter tracks. The new Traxxas system falls right between. Top speed is just as fast or slightly faster than my MM5700 and the control is almost as good as the Novak sensored stuff. Keep in mind that I quickly got away from Nicd & Nimh batteries and have run Lipo's only for about a year and a half ( I beleive this is what kept killing the Novaks). If you want excellent control go Novak, killer acceleration and top speed and the finess of a shotgun go Mamba. But lately my money has been going to Traxxas.

[Helgaiden]

wow thats good for traxxas i guess lol.

Anyways, reliability on the novaks (13.5 gtb system to be exact) with 6cell NIMH packs is better i assume? Just mentioning that cuz i interpreted your LIPO killing your novak stuff as being the Lipo's fault...

but i could have misinterpreted :P

[GSMnow]

john91374 wrote

<<If you want excellent control go Novak, killer acceleration and top speed and the finess of a shotgun go Mamba. But lately my money has been going to Traxxas.>>

I have driven brush motors of virtually any wind on several different speed contropls and I have driven my Mamba Max 5700 in some very hairy track conditions as well as open cruising. The hair trigger shotgun award goes to a low turn brush motor on a 50 hz frame rate ESC. I had a couple motors that would not turn until well up in the throttle, and then they would jump to 10,000 rpm. The Mamba Max has very smooth linear control down to a crawl. "Geared properly" it will easilly drive around at 1 mph while being able to top out over 30 mph with accelleration potential to smoke the tires and/or wheelie at any speed in between. I think MANY people are confusing lots of torque with a lack of smoothness. The difference is that the smoothness of the power delivery is now in the finger of the driver. If you limit the current potential of a system it will appear smoother because it will not be able to yank the wheels from 20 to 30 mph in a blink like the Mamba Max can do at the will of your trigger finger. If you roll your finger on smooth, it will increase the wheels speed just as smooth as you move the trigger. I have not found the resolution of the system, but it sure seems like more than the typical 256 steps of an 8 bit system. Imagine a car with a perfect linear throttle, but it was on an engine with 2,000 lb ft of torque available from idle to redline in a 500 pound car. If you open that nice smooth linear throttle too fast the tires spin. BIG SURPRISE. The very nature of the Mamba Max is this massive torque at any speed. It does take a while to get used to driving with that torque there at any time. Rolling side by side with a 1/8 nitro buggy, I can jump away before his revs climb. I only loose in a straight line when the 4wd give enough of a traction advantage which is only out of slowish corners where I spin out if I pull too fast.

The tiny, usually unoticed, hickup from a dead stop is the only thing where the Novak wins on smoothness. For a rock climber, sure, go sensored for the rotor control at ZERO rpm. The Mamba Max 5700 motor has to get up to about 1,000 rpm before it becomes smooth, but once it does go closed loop back EMF sensing, it can go even slower before it drops back to open clocking start mode. I have even crawled it up a 40 degree hill at about 1/2 mph with it geared to go 33 mph. If I was rock crawling and geared it to go just 8 mph tops, it would certainly work as a total crawler.

After abusing my MM5700 system, I can certainly attest to the reliability of it. Just loose the supplied bullet connectors between the ESC and motor. Mine acted up after 3 or 4 race days. Thought I cooked the ESC. Switched to deans plugs and it has been rock solid ever since. Also seal up the motor where the wires go into the can. Dirt WILL get into it.