Boost

[steelo 93]

Hi everyone,

I was running my cars with my friends 10 year old son and he wanted to know if you can add nitrous to an electric car...after looking at him and trying to keep a serious face I attempted to explain it wouldn't work on electric vehicles.....I think his mom lets him watch too many f&f movies...LOL

It got me thinking though, would it be at all possible to add a capacitor or even a small battery that can release extra voltage controlled by a 3rd channel? The only way I could contemplate this would be to use some kind of relay, activated by channel 3.

I know it isn't at all practical and just kind of silly (just throw in a 3s if you want it to go faster), but it would be a kind of neat use of the third channel on a receiver.

[speedy_w_beans 4272]

There are speed controls and brushless motors that include "boost" and "turbo" as additional parameters to tune. These affect the timing of the motor and actually increase the potential speed and efficiency of the motor across the rpm range, which results in higher speeds than you can normally get from fixed timing motors.

So, yes, you can get boost for an electric car; it just requires the right electronics to make it happen.

[steelo 93]

Thanks, I know they have ESC's with 'boost' but I'm wondering if anybody has tried making use of a 3rd channel to 'boost' at a touch of a button.

[Nitomor 2122]

Go brushless then limit the throttle curve on the radio and then with a switch allow full throttle. Can be done on a programmable radio, like the Futaba FF7 for example.

[steelo 93]

Ah, good idea thanks!

[MadInventor 3884]

Ever sprayed isopropyl alcohol cleaner into a brushed modified motor when it's running ? I did this cleaning a motor and there is an audible increase in rpm for a couple of seconds

I'm not suggesting you try adding a can to a car (Don't try this at home kids), just thought it of interest to note you can get more rpm from a motor by spraying liquid into it .....

[LongRat 616]

What you are taking about is available in fact. Electronic boost from an auxiliary channel for just $20. I have not used it myself.

www.hobbyking.com/hobbyking/store/__52026__Turnigy_ENOS_In_line_Electronic_Booster.html

[speedy_w_beans 4272]

I'm surprised something like this exists. The extra space to mount it, fiddling with the third channel switch while driving (ergonomics), and only getting 1 second of "boost" (see review at bottom of product page) all seem to stack up against it. The friend's son would be better served with a 7-cell NiMH or a 3S LiPo with extra speed on tap anytime he wants it.

[LongRat 616]

Probably a fair point.

[Nobbi1977 1793]

The problem with an electric motor is that all the torque is available at start up so extra punch when running at speed will seem minimal compared to a fuel motor which has an opposite torque curve. I like the idea of a boost button though,just for the cool factor.....

[Wooders28 4723]

You could run it through a relay and an extra nicad/ nimh cell. Relay open= 7.2v feeding motor, relay closed = 8.4v (+) with extra cell in series to the motor?

You can then say,' It'll easily take a bigger hit,I'll just up it a bit' with another cell etc until you blow the motor! Just like nitrous

If it's a 6v output from the receiver, then it should be fairly easy to do?

Fit the extra cell to the front like a moon tank, or colour it the same as a nitrous express,zex,or nos bottle!!

[steelo 93]

I was thinking the same thing. Run a 1.2v rechargeable battery or a cell in series to the motor and activate the relay via ch 3 closing the circuit and running the additional battery voltage to the motor. Would probably need a diode to avoid the extra voltage from dumping into the esc. Not sure though if the receiver will output enough to activate the relay. Also not sure what relay to buy.

Also how would I charge a single 1.2v cell?

Chances are i'll never try this but it does have a 'cool factor' sense of appeal

[Champ85 609]

Just set your ATV to 75% for normal running, and when you need "boost", just switch it to 100%. Bingo, more speed and no funky extra cells or relays required.

[steelo 93]

I lnow there are much better ways to do this...If I wanted to go faster, I would just buy a 2s or a 3s. I just think it would be neat, especially if I paint the cell like a nitrous bottle and add labels =)

Another problem is its a brushless motor...

[Wooders28 4723]

I think the best way (and not to dissimilar to full scale,as I don't know anyone that runs a button like on f+f) would be to run a mech speed control,but set it so full normal power is 3/4 on the stick,then position a microswitch so that it's triggered when full throttle is applied.

To charge a single 1.2 cell,just bung it in the normal household battery charger.

[speedy_w_beans 4272]

Since you have a brushless motor in the car already, if it's a sensored setup then look at the Turnigy Trackstar 120A Turbo ESC and associated programming card. The turbo setting activates at full throttle for a programmable amount of time with a programmable amount of timing advance. No micro switches, relays, or extra batteries required. Plus it will be "cool" to him when he can plug in the program box and change parameters like the computer geeks in the F+F Tokyo Drift movie.

[Wooders28 4723]

No micro switches, relays, or extra batteries required. Plus it will be "cool" to him when he can plug in the program box and change parameters like the computer geeks in the F+F Tokyo Drift movie.

Everything's tappity tap these days,bet there's even an app for it!

Back in my day.......

[mr crispy 2293]

Cool idea. You could cheat and do what Tyco did with the Turbo Hopper transmitter. The throttle had a kind of stopper on it at about 90% power. You would normally only push it up to that while running, but you could also push it past the stopper for 100% and it revealed the word turbo or boost at the bottom of the throttle stick. It was just a simple decal stuck on the curved plastic but it felt good to hit that as a kid 😋

Or you could forget any electronic motor setup and connect an electric match to a model rocket motor and JATO the mother! 😜 What kid isn't going to like a huge cloud of smoke accompanied by flying debris!

[steelo 93]

Thanks, I was wondering if I could use a normal household charger. I would use a nicad cell from a very old battery pack that amazingly is still good.

With it being a brushless set up, I would have to run the extra cell in series with the ESC instead of the motor. It's a TBLE-02s ESC that folks use 2-3s lipo's with so I think it can handle an extra 1.2v and still be fine...still researching what type of relay would work, don't want to spend more than a few dollars for the part =)

One more question, what is the typical output voltage from the 3rd channel of a receiver? Would it be enough to trigger a simple mechanical relay?

I do like the rocket motor idea, but I also don't like rebuilding burnt up/destroyed models =)

[LongRat 616]

The signal out of a receiver is not simple DC, it's a PWM signal. You need a circuit to interpret this and switch the relay. Such devices as 'RC switches' are available for this purpose. However doing this relay thing is just an altogether bad idea. The relay would need to be huge to handle the current without immediately fusing. RC switches are designed to switch on LEDs and the like, not to run motors flat out.

[steelo 93]

I was afraid of that....the current that will be running through the relay would only be 1.2v, basically an extra cell running in series.

I thought that PWM signals can trigger DC relays/transistors if they have the ability to switch quickly enough.

[LongRat 616]

The current that will run through that extra cell is the same that will run through the whole pack of seven in series. Like 30A continuous with a spike of a lot more. The fact it's a 1.2V cell is not an important issue here. The PWM thing is a way of approximating an analogue voltage by switching the full voltage on and off very quickly. You certainly don't want to be trying to switch a relay at PWM frequency. You need the PWM interpreter. You can actually hack an old servo to do this but it is pointless - you still have the relay issue to deal with.

[steelo 93]

Ugh....sounds like this will be more trouble than it's worth!

Thanks for all the input, had no idea this would be so much work =(

[Ozzycat04 6]

Back in the 80's me and my best mate used to strap a firework to the body and half a dozen swan vestas to the wheelie bar,and hey presto uncontrollable boost

[steelo 93]

LOL...good times!