speed controller for fisher price

[Aren_Hill]

i am converting my ofna pirate 10 to and electric because the engine always gave me problems and i have 2 fisher price motors i plan to use both of, I am just wondering if there are any cheaper speedcontrollers than a victor 884

[sanddrag]

The victor is the only thing that comes to mind that would handle both motors unless you build your own. If you want it to be forward only and controlled by a servo actuated pot, then it is actually fairly easy to build your own. It probably isn't too much harder to build your own with reverse and pwm input. How many cells do you plan to run? A Novak Super Rooster would probably do it but it is just as much as a victor. Actually, my recommendation would be to get a used (but with guarantee) Novak EVX off of eBay and run two stick pack for 14.4 volts. That's your best option since that ESC is made for two batteries and two motors and you'll get awesome performance. Should be able to get it for about $60-$90

What problems were you having with the nitro engine? Was it an ofna engine? They are notorious for air leaks. I've had alot of troubles with mine as well (TRX Pro .15). I was almost ready to sell the thing. But then I finally figured it out and now it starts every time and runs great.

Nitro engines can be quite reliable with the proper tuning and starting procedures. Let me know fi you need any help if you want to stay with nitro.

PS. I'm going to be starting on a weedwhacker powered RC simply for purposes of reliability. :)

[rufu5]

http://www.robotmarketplace.com/marketplace_speedcontrollers.html

that is a wide array of speed controllers, vantac is usually pretty cheap but you need to make sure it will handle your voltage and amperage requirements

[John Gutmann]

You should be able to use like a futaba, or likea XL-1 or XL-10 depending on what the current the motor draws is and if it isn't brushless.

I have TONS or MSC (Mechanical Speed Controllers) if you need any. Just PM me.

[Aren_Hill]

i've just decided to try using a drill motor from a dewalt instead since one motor seems like it'll give plenty of power. As far as mechanical or electrical speed controllers i want to be able to brake and reverse the motor so i can stick with my 2 channel radio
i'm probably going to end up buying a victor because i know they are reliable and i can use it with a single drill motor or the 2 fischer prices and i'll be able to use it for other things.

i'm wondering what i'll need for batteries will 1 stick pack be enough for a decent runtime or should i wire 2 in parallel?

I'm doing this because 1. my engines is unreliable
2. i have some motors sitting around and want to explore the electrical side of things

so if i can find a mechanical speed controller that has breaking and reverse and smooth operation i could use that

thanks,
aren

p.s sanddrag do you think the novak rooster would work for the drill motor?

[John Gutmann]

From what I remember, victors only use a unique PWM signal that you can only create with IFI controllers.

Correct me if I am wrong.

[fimmel]

they can be used w/ any pwm that has the correct timeing.

[sanddrag]

I don't know if hobby RC receivers will give the proper signal to work with a victor. It says they are not for use with hobby RC equipment. There is a "signal driver" cable at the bottom of this page http://www.robotmarketplace.com/marketplace_ifi_acces.html that may be required (also direct from IFI on this page http://www.ifirobotics.com/victor-883-speed-controller-robots.shtml)

Also, you should note that the Novak EVX (http://www.traxxas.com/products/accessories/trx_accessories_evx.htm) has smart braking and the victor has jumper selected braking (when the throttle value is neutral) only.

[Andy A.]

Victors will work just fine with typical R/C gear. Signal drivers are not neccesary. You will have to calibrate them, naturally, but after that they work just peachy. Forward and reverse will work just fine, although reverse will be over a very small area of travel on the trigger. Aircraft receivers are another story- some channels use a normal PWM signal and others don't. I have not been able to figure out a real guideline for them, as I've only played with 2 or 3. For a normal 2 or 3 channel radio you won't have any problem.

You will need to use more then one 7.2 volt battery pack though. 7 volts is not enough to run the victor (the voltage drop as the motor starts turning will shutdown the victor). I suggest you use two in series. The Victor will be no worse for the added voltage and the motor will run faster. I also remove the fan on the Victor.

Go forth, and enjoy the world of overvolted drill motors.

[John Gutmann]

I also remove the fan on the Victor.


I do know that, that^ is a terrible idea.

[Aren_Hill]

i'm going to test operating a motor with one of my teams victors and if it works i'll probably get my own

[Matt Krass]

I do know that, that^ is a terrible idea.

While at the low current draws involved with R/C motors the FETs are probably dissipating considerably less heat, I see no practical advantage to turning them off, and there's always that fluke power surge. I'm curious Andy, do you gain anything significant from removing the fans?

[Andy A.]

While at the low current draws involved with R/C motors the FETs are probably dissipating considerably less heat, I see no practical advantage to turning them off, and there's always that fluke power surge. I'm curious Andy, do you gain anything significant from removing the fans?

First and foremost, the advantage is a reduction in both weight and hight. If I am putting a Victor on a car it's because I intend to make it go fast. It might not seem like much, but one of those fans is hefty. Weight negatively effects every performance aspect of an RC car. So if it isn't mandatory, it goes. Losing the fan also cuts down on the victor's height, which makes it a bit easier to package. The victors are already much larger and heavier then typical hobby speed controllers and demand a larger battery source, so any weight or size reduction makes a big difference.

Using a Victor means trying to make up the weight gained from the extra cells needed to run it. Even with the increased capacity and features of the victor the extra weight makes it a hard pill to swallow. The price, which is to say free, makes up for a lot in my mind but it is still an hard trade off.

After that it's just the shear pointlessness of the fan to start with. On a FIRST robot running a full 2 minute match, the Victors running drive motors might get toasty enough to need the fan. Running one motor moving less then 5 lbs and there is no way that the FETs will produce enough heat to warrant a fan. They just won't. Honest. The popular notion that removing the fan or not having one running for ever moment the victor has power applied annoys the heck out of me because it's so utterly false.

I've run many small RC cars with a victor/drill motor or FP motor setup and have never once found the victors to be anything but stone cold. I have never once seen a Victor fail because the FETs overheated (short circuits not withstanding) Heat is simply not the big killer issue that people make it out to be in regards to the Victors. If you are really worried about it just position the victor so some air passes over it through the body, but don't bite you're nails about it.

The fan really is overkill on an RC car. Ditch it and worry about balence and where to stick the extra battery pack.

-Andy A.

[Matt Krass]

First and foremost, the advantage is a reduction in both weight and hight. If I am putting a Victor on a car it's because I intend to make it go fast. It might not seem like much, but one of those fans is hefty. Weight negatively effects every performance aspect of an RC car. So if it isn't mandatory, it goes. Losing the fan also cuts down on the victor's height, which makes it a bit easier to package. The victors are already much larger and heavier then typical hobby speed controllers and demand a larger battery source, so any weight or size reduction makes a big difference.

Using a Victor means trying to make up the weight gained from the extra cells needed to run it. Even with the increased capacity and features of the victor the extra weight makes it a hard pill to swallow. The price, which is to say free, makes up for a lot in my mind but it is still an hard trade off.

After that it's just the shear pointlessness of the fan to start with. On a FIRST robot running a full 2 minute match, the Victors running drive motors might get toasty enough to need the fan. Running one motor moving less then 5 lbs and there is no way that the FETs will produce enough heat to warrant a fan. They just won't. Honest. The popular notion that removing the fan or not having one running for ever moment the victor has power applied annoys the heck out of me because it's so utterly false.

I've run many small RC cars with a victor/drill motor or FP motor setup and have never once found the victors to be anything but stone cold. I have never once seen a Victor fail because the FETs overheated (short circuits not withstanding) Heat is simply not the big killer issue that people make it out to be in regards to the Victors. If you are really worried about it just position the victor so some air passes over it through the body, but don't bite you're nails about it.

The fan really is overkill on an RC car. Ditch it and worry about balence and where to stick the extra battery pack.

-Andy A.

What you say makes sense, thanks for clarifying that. How much current does an R/C car typically draw though? Wouldn't it make more sense to go with hobby ESCs then? Or is use of Victors a convenience since they're readily available or something? Or do they offer some kind of power boost?

Sorry if I'm asking too many questions, I tend to get curious :)

[Andy A.]

What you say makes sense, thanks for clarifying that. How much current does an R/C car typically draw though? Wouldn't it make more sense to go with hobby ESCs then? Or is use of Victors a convenience since they're readily available or something? Or do they offer some kind of power boost?

Sorry if I'm asking too many questions, I tend to get curious :)


The use of victors came about after James and I did a thesis project together. During that time, 95 donated a lot of old victors, wiring supplies and even an old Pbasic control setup.

The project was great. Afterwards, no one was really interested in taking back the equipment and we had a summer to kill. So we started retrofitting old R/C cars that people would donate or found on ebay for cheap. We developed this mantra of 'make it fast and make it cheap'. Most of the cars we had we're old clodbusters and Grasshoppers. Either they had no electronics or old servo actuated speed controllers. We didn't want to spend any money so we just started using what ever we had on hand. That meant victors, FP motors, mixed R/C gear and so on. The first cars were just the leftovers of Dex, but I think ended up being more fun.

After a while we got a little serious about it and produced some very fast and capable cars. They wouldn't have fared well in a serious race, but in the backyard and on the street they were brutally overpowered. It was something of a MOPAR thing. We liked have an R/C car that would break the rear tires loose on carpet. Some cars even got a custom aluminum chassis and battery pods. I am quite proud of some of the stuff we were able to bang out for next to nothing. On a good day they could go toe to toe with my Violator* and keep up.

The victors are decent speed controllers, but like I said, overkill. Their biggest benefit was that they are cheap/free and will handle any thing we throw at them. If someone wanted to give me an assortment of hobby ESC's that had comparable performance, I would use them to.

And I am happy to answer questions. Like I said, I am still very proud of the stuff me and James made in his basement. We have a few robots in production, but most of the cars have been stripped for parts.

Its a heck of a hobby.

-Andy A.

* My OFNA Violator has a .21 Pico engine, and I've never had any trouble getting it started or tuned. Leaned out that sucker is _fast_. I don't run it to often for want of a good open space to do so, it's just to much for a backyard.

[John Gutmann]

The reason I said what I did is because I know that the traxxas XL-1 I believe I saw that can handle up to 150 Amps, and with how light the cars are I figutred they must be turning somewhere close to the free speed RPMs. I just figured it would have drawn more current then I thought.

BTW, andy have you ever seen a 4 turn motor on a lightened chassis take off? ;) It could prolly keep up with a 3.3 and deffinately atleast 2.5. Not that I have one yet but I am getting there.

Also what kind of motors were you using wen you finally got it to go that fast?

[Andy A.]

The reason I said what I did is because I know that the traxxas XL-1 I believe I saw that can handle up to 150 Amps, and with how light the cars are I figutred they must be turning somewhere close to the free speed RPMs. I just figured it would have drawn more current then I thought.

BTW, andy have you ever seen a 4 turn motor on a lightened chassis take off? ;) It could prolly keep up with a 3.3 and deffinately atleast 2.5. Not that I have one yet but I am getting there.

Also what kind of motors were you using wen you finally got it to go that fast?

There is a big difference between the typical FP motor and a hobby motor. In most cases, the hobby motor is going to offer a higher top speed. The FP motors seem to be more hardy and torquie. Lacking dyno or any spec sheets for hobby motors this is a purely subjective rating.

The retrofitted cars where never as fast as the nitro car in a straight line. They did however do much better in turns and overall ease of handling. The great fun of them was that at nearly all throttle positions under 100%, snapping it into full throttle would break the tires loose on pavement. This allowed for some impressive controllable oversteer and drifting. The Violator on the other hand is a big, heavy pig when turning. The power is impressive but it tends to slog through turns and isn't nearly as nimble or easy to 'toss around'. One day I may suddenly get better with her, but I'll have to fight for every bit of speed out of her. The electrics just worked.

There are on road cars that could beat the snot out of anything I could make on a paved track. But those cars can't take off on a grassy yard or on a dirt road either.

The fastest we ever got a car came from using the dreaded 6 volt FP motor from a few years ago. We ran it at 14.4 volts and had a blast. I think it eventually died or dropped off in performance, but man did it scream. That motor worked well because it's RPM range was right inline with a normal hobby car, so the gearing was all being used. A normal 12volt FP motor is way under geared and tops out at about 30mph, but will tow a van while it's at it.

-Andy A.

[Aren_Hill]

i've tested the dewalt motor with a victor we had and my 2 channel radio and receiver and it works beautifully. i'm going to order a victor soon.
what would you suggest for batterys a drill pack, 2 stick packs, lantern battery?

when i ran it with one 7.2 volt pack the power drop killed it so i couldn't acclerate then i tried a 12 volt battery and this thing'll wheelie right over i bet

[John Gutmann]

Try putting 2 7.2 packs in series to creat 14.4 volts. Or maybe a 8.4 volt pack if you have it. Atleast if you get everything in the car then the hardest part will be done.

[Andy A.]

Anything less then a 9 volt battery pack will be useless to you. Even then you will probably have a lot of brown outs.

My first choice is two 7.2 volt nicad packs in series. It's heavy, but the performance is great and you'll have at least 15 minutes of run time. The packs are inexpensive on ebay and easy to charge. James and I used to use a DeWalt smart battery charger with some leads, so if you have one of those you are set.

We still use our packs, although we've since bought an easier to use charger. Right now the packs are used to run the chamber fan on our cannon, but all our cars and 'bots are set up to use them. It's nice having a bullet proof power source for all our debauchery.

A drill battery pack works, but it'll be clumsy. If you just want to try the car out then it's a great way to get things running quick. Otherwise, invest in some battery packs.

And remember- Calibrate that Victor!
-Andy A.

[Aren_Hill]

thanks for the info guys i'm ordering a victor and have figured out where everything will go on the car i'll post some pics when i finish.
i've also decided to do 2 7.2volt packs in series from your recommendations

i've made an structural modification adding some aluminum to strengthen the shock towers.
i still also need to make a bracket for the drill motor and get the right gear on the motor. Any idea how to take off the old gear off? it doesn't want to budge so i may just press an aluminum collar over it and work from there.

for space purposes i will be taking the fan off of the victor but its in a position where there will be lots more airflow than the fan could provide so it should stay cool.

aren

[John Gutmann]

If you want airflow around the victor, cut the winshield and side windows out of the body.

To take the gear off the fisher price motor you will need a gear puller like shown (http://www.andymark.biz/gear-puller.htm).

Also I looked at the specs for the fisher price motors and they seem to have 15,000-16,000 RPMs so in the tranny get as small of a ring gear as possible and get as big of a gear for the motor as you can. I know that an 11 turn motor has somewhere in the range of about 27,000 RPMs so considering your car probally came with from a 20-27 turn if you gear it up as much as possible it should beable to hopefully burn out.

Take pics of everything.

BTW I dont know what kind of transmission is on a OFNA car but on my traxxas Rustler it uses mounting holes on the motor case. so if it does mounting should be EASY because from the comparisons I have done they RC motors and the FP motors seem to have similar if not the same case.

[Aren_Hill]

i've uploaded a picture of the car witha victor 884 and two 7.2 volt packs on top the receiver and the batteries will be under the aluminum right now i'm still working on it it burns out no problem