Making an esc better?

[BrianG]

Like I said before, the Quark seems to sacrifice a bit of efficiency in favor of smooth running. To me it's worth it. I'd much rather add a little extra heatsinking than have an ESC that stutters, but that's just me.

If you are running a Neu on the MM and don't mind a little experimenting, try adding an extra capacitor or two to the battery inputs on the MM. They have to be low ESR types. Figure on two 220uF and 35v if you can fit it, or one more 330uF if not. Solder it directly to the + and - battery solder pads on the ESC. I'm going to try this someday, but I don't have a "bad" running system to see if it helps.

I suppose it can be discouraging to spend all kinds of cash on something that doesn't work up to expectations. Stick with it if you can because once you get it running, you'll be happy.

Mechanical controllers would be a bad idea. Those are usually servo driven and rely on resistors to drop some of the voltage to the motor so it goes slower. And dimmers are different; they use triacs on the 120v AC line and chop some of the sine wave off so the light/fan gets less power (I can go into more detail on this if you want, but don't think you really want to hear it, lol). They rely on a sine wave though, so it wouldn't work in R/C. IMO, the use of many paralleled FETs is the way to go - it's just up to the manufacturer to use them appropriately in their designs.

I do have to give credit where credit is due. From what I could see, inspite of not being able to program it, the Compro is going to be cog proof. It starts a bit abruptly, in that even easing on the throttle results in the vehicle just going, rather than easing into a roll; but it never cogged, no matter what the gearing was and it ran down right cold.

I could solder up some caps on the MM, but what would this accomplish? My assumption would be that it would help out the batteries, if they were unable to supply the current demanded of the system, but I'm running Kokams and they have no problems supplying current.

And yes, it has been discouraging. This whole ordeal with the Compro has about assured the death of my passion for rc cars/trucks. I would have just ordered another one to use while I was waiting for mine to get fixed, but something told me that it would be stupid to do so. If I do stick with this stuff, I'll be ordering all of my more delicate equipment from my LHS; and if they can't get it, I won't mess with it. I found out last week that they can get Quarks, so at least I'll have a line on the S&T, Castle, and Tekin stuff. I'll probably pay more for it, but I'm willing to pay for the service.

[BrianG]

Soldering extra caps on the power line (as close as possible to the PCB) may help with the Neu cogging issue. The idea is that the Neu is a highly induictive motor and needs more to absorb the back-emf pulses. If you have a Neu and some caps, great. If not, then I wouldn't bother.

[GriffinRU]

I am getting some blown ESC's from Mike, so updates will come later...

[BrianG]

Griffin, while you are at it, can you look at the possibility of hooking up another MM in parallel to the master so you can have double the capacity and cooling? Of course, the "brains" of the slave would have to be disabled/disconnected...

[GriffinRU]

Originally Posted by BrianG

Griffin, while you are at it, can you look at the possibility of hooking up another MM in parallel to the master so you can have double the capacity and cooling? Of course, the "brains" of the slave would have to be disabled/disconnected...

If I get MM for testing then sure why not.

[BrianG]

I guess it could be done with any controller, not just the MM, but it looks like the MM would be the easiest the way it's built...

What I'd really like to see is a tiny controller with just the brains (with USB programmability) with a short umbilical to power board modules. Keeps the power and heat away from the brains and maybe cheaper/easier to replace a burnt power section. I doubt anyone will ever make a modular ESC like that though...

Well, once my Quark gets here, I may just have an extra MM to offer up to the RC gods.

[GriffinRU]

Originally Posted by BrianG

I guess it could be done with any controller, not just the MM, but it looks like the MM would be the easiest the way it's built...

What I'd really like to see is a tiny controller with just the brains (with USB programmability) with a short umbilical to power board modules. Keeps the power and heat away from the brains and maybe cheaper/easier to replace a burnt power section. I doubt anyone will ever make a modular ESC like that though...

Thats the future plan, like industrial controllers, 6-pin header with opto-isolation and no limits.

[BrianG]

Originally Posted by AAngel

Well, once my Quark gets here, I may just have an extra MM to offer up to the RC gods.

So, you did end up getting the Quark. I thought you were going to wait to see about the MGM warranty thing? Maybe I missed a post somewhere...

Griffin; yeah, that'll be nice. Probably be at least a few years before that comes about though...

Yeah, I ordered a Quark from my LHS. I didn't know that they could get them, but when I found out that they could, I ordered one.

The Compro is a wash. Once MGM determined that it wasn't a hardware problem, which is what I told them, they refused to believe that I could be having a software problem. They wouldn't tell me what I needed to do to send it in and now won't even return my emails. I got totally hosed. That's how it looks right now anyway. I'm going to try to email them a few more times, but I'm not feeling too confident about it. I'll probably sell it cheap or just throw it away at some point, if I don't find a use for it. With that motor braking, it might do OK in an on road car. Since there's going to be a whole lot less mass all the way around, it might not tear up the gears like it's doing with my truggy.

I was getting serious about switching to helicopters. The T-Rex is nice, but I want to get this truck right before I move on, just so that I'll know that it'll run like it's supposed to if/when I do need it.

I'll just run the Quark until something better comes along. Since I ordered it, I've done a bunch of reading up and it appears that the Quark has its own issues. It figures, but it's the best that available right now.

Griffin, it is likely that I'll have a MM to send you to "play" with. I'd just like to know if there is a possibility that I'll get something back that I'll be able to run at some point. Just to be able to say that I have something different.

[BrianG]

Oh yeah, now I think I remember you saying something about getting it from your LHS. The Quark does have it's issues, but as long as you cool it well and don't run any higher than 5s, you should be fine. No matter what, all ESCs have the potential to burn up.

Also keep in mind that the Quark is technically a 1/10 scale ESC, according to another post from somewhere here. You should be fine, but don't expect miracles if you try to hook an LMT 3080/5 on it. ;)

[zeropointbug]

Yeah, I have said this before, but I would like to see AC induction systems for RC. Particularly, from Rasertech, they have an Induction motor tech. with same power density as these brushless motors, and same efficiency (but, better at partial load). I think overall they would be a much better system that BL power, reasons being:

-extremely durable (AFA heat, and no magnets)
-more resistant to shocks and vibration, and extremely high running temp able
-glass smooth torque under all loads/speeds (no torque ripple, or cogging)
-able to turn off magnetic field (BL is always on)
-much less expensive
-more control over motor power/excitation

To me, that makes a better motor.

ZPB

[BrianG]

I'd like to try one of Rasetech's alternators. It would be nice to have 100A+ on tap near idle compared to the measely stock one...

[zeropointbug]

yah, those do look tempting, especially with a heavy audio system, but also audio capacitors help big time.

I wonder what the next motor WILL be for RC? The inverters for an RC sized motor would be simpler and smaller than BL controllers as well.