Brushed ESC with 50% Power Boost
 

Hello Everyone,

This is my first time posting, but I have followed the forums for quite a while. I have been interested in RC cars since the late 90's (never raced, just at home), but due to other responsibilities the time I've had for them has been fairly little. I am an electrical engineer, with a primary focus on power electronics. In late 2005 I invented a completely new brushed speed controller technology which was capable of boosting the power of the motor by up to 50% (actually could go more, but the motor will burn out too quick). At the time I made a prototype, and it was a blast! I set it up with different modes. One mode would just give you additional power in the normal throttle action (70% throttle was 100% power, 100% throttle was 140%, for example), the other mode was sort of a double click action, where you could enable and disable the boost. I thought this might be pretty desirable, especially for people who race in stock classes. Also, in my limited exposure to racing, it seems that the full throttle isn't used that often, and that people might like the added efficiency of a less modified motor, but the ability to get a power boost if they need it. I contacted ROAR and they confirmed that there is no restriction on the ESC whatsoever.

At the time I considered attempting to commercialize the design, but as it was more of a hobby, and I had a lot of other more important things to worry about at the time, so I decided against it. I also was thinking that brushed motors are on the way out, and that it might be a situation where it would have been better to come up with it 5 years earlier. Another consideration I had was that some people might consider it cheating, and it would eventually be banned from racing. If that was to happen, then it would probably have even less relevance, since you could always just get a faster motor.

Some reasons you would still want it if it was banned from stock races might still be that you like the added run-time from having a more efficient motor, or maybe you like buying cheaper motors. The big downside is that it probably degrades the motor faster the more you operate above 100% power.

I'm writing this post because I'm looking to hear from all of you much more experienced drivers to see how you perceive the pros and cons of my speed controller, and to see if it is still worthwhile pursing. Now brushless motors are even more prevalent, so maybe there just isn't much demand for it. I have more free time now, so I could get back involved, but I'm just not sure if it is worth the effort.

Please let me know what you think!

RE: Brushed ESC with 50% Power Boost
 

What is this, just a step up for voltage? If you're not stepping up voltage, ThunderbirdJunkie doesn't understand how you're giving a brushed motor a 50% "boost". It's not like a brushless ESC where timing can be electronically manipulated to gain RPM/power. More to the point, additional components to step up voltage adds complexity to the ESC, which is never a good thing when heat is involved. In modified classes, there has never been a shortage of power. It's more to the point that the chassis simply can't put any more power down. If you drive a 2wd 1/10 buggy with a 10x2, you'll understand.

Hardly anybody races with brushed motors outside of spec Slash classes anymore, so this is probably one of those situations where it's too little/too late, and those that do race with brushed motors are running their old gear and won't bother spending any money on a new ESC if it's not a brushless controller (ThunderbirdJunkie is a good example).

RE: Brushed ESC with 50% Power Boost
 

Yes, the effect is higher voltage when operating the boost functionality, but normal operation for lower throttle. There are other ways to get this functionality, like having a DC/DC converter after the battery or something like that, but that would add a lot of size and weight. The way I do it only adds a small amount of size and weight, and doesn't effect the performance when you aren't using it. Either way, I guess the point remains that people don't really use brushed motors anymore. This is what I thought back when I made it, and now it is even more true I guess! Maybe I'll just make a handful and sell them to rich guys in stock races :)

Also, I like how you talk about yourself in the 3rd party, DrCalculator thinks it is a nice touch! ;)

RE: Brushed ESC with 50% Power Boost
 

That makes sense, kind of like the ramping timing/boost in modern brushless speed controls, IE if you're WOT for more than half a second, it advances timing, etc etc.

Pretty cool idea...do you think you could adapt it to a brushless motor controller? That would sell.

RE: Brushed ESC with 50% Power Boost
 

yes in a brushless system that would be great have a esc that is rated for 11.1v or 14v and with either a button or pull the trigger twice you get a voltage boost that would be great even if its a short term boost. problem Isee is brushless motors have voltage limits and you would still need to upgrade your motor unless its rated for a 4s and your running a 3s the voltage boost would bump the voltage from 11.1v to 14v for a few seconds. I would buy that.

RE: Brushed ESC with 50% Power Boost
 

ThunderbirdJunkie sees the biggest advantage in superstock 13.5 touring car where timing and boost are allowed, but you must run a 13.5. Most 13.5s are 3000-3500kv motors, so most will take 3S voltage. Even if it's a modest (10-25%) voltage bump, that would provide a significant advantage in stock-ish racing.

RE: Brushed ESC with 50% Power Boost
 

Yes, it can also be applied for brushless motor controllers, but it is more complex. Also, there is a lot of additional work in general with making a brushless controller that has all of the features of other controllers on the market. It might be a situation where I could find a smallish manufacturer who is willing to work with me on improving their existing product line. I am a partner in a small power electronic R&D company, so I am used to arrangements like this.

Do you think that it would be ultimately outlawed for most racing classes? In my limited use, there was a general consensus from others that it was unfair. :)

As far as the motors, most motors can take some extra abuse for a short time, so as long as you don't go nuts with it and maybe look at cooling the motor a little more seriously, there shouldn't be any issues for occasional use. With my prototype I didn't see any significant damage to the motors. The theoretical maximum amount voltage I could get was about 170% of the battery voltage, but this is too much for a motor to handle for long, so I capped it at about 130% of the battery voltage (70% extra power).

RE: Brushed ESC with 50% Power Boost
 

The root problem is, the biggest benefit a setup like this will have is in a stock-class (17.5/25.5/27t) car, and they've gotten pretty anal about stock class ESCs with timing and such, so it wouldn't last long.

There are a lot of tracks that run superstock-type racing, so that's probably where this would shine, and get the most use...but it may be one of those "great idea...where the hell you gonna use it?" type of things.

RE: Brushed ESC with 50% Power Boost
 

I'd buy it just to have it, i run mostly brushless set ups but i'd love to give this a try seeing how brushed motors are cheaper.

I want one!

Did you manage to apply this to vape technology?
 

I have a use for this outside of the RC realm. For an older full scale car's blower motor.