TQ10 Motor gets hot

[Ravenwoods]

I know almost nothing about radio control stuff. Someone moving away gave me an old TQ10 Graphite car with a Futaba Attack Controller and a Panda Ni-cd battery charger. Only thing missing was a battery. So I got a 1800 mah battery on Ebay. After the battery arrived I took the car out for a test and within 5 minutes broke one of the front arms in a collision with a curb. So today the new arms arrived in the mail and I installed the new arm

I took the car out for another test and after about ten minutes the car suddenly did not go any more so I thought the battery must have gone dead. Put it on the charger for 20 minutes. Sent my daughter out to test drive the car. After about 15-20 minutes she comes back and the car had stopped again. The motor felt very hot -- too hot to touch. You could smell the heat.

So is that normal? Should the motor get that hot. Battery was also very warm.

I just put the battery on the charger again. How long should one charge last? It is an Onyx 1800 mah. I thought that when the battery starts getting weak the car would just start going slower. What is normal?

[RC10th]

I assume the car has an electronic speed control? If so it is probably thermalling and shutting down, have you checked how hot it gets? You should be able to touch the motor and hold it for at least 5 seconds. What motor is it

Is the drivetrain free? If it had been sitting a long time the grease can dry up and make the gearbox tight. If he was racing it it would probably be geared for racing which is 5 minutes, so running it for 15-20 would be at three times longer.

Try a couple of teeth smaller on the
pinion and see how you go.

[mk-Zero]

Motors and batteries can get pretty hot, its fairly normal. Generally motors are suggested to keep below 180 F. If the guy you got the car from was running a LiPo battery he probably had the speed control set up to cut the motor out when the battery gets down to about 6.4 v. LiPos need that protection because they can get damaged if they get below a certain voltage. NiCads dont have that issue. You may be able to disable that voltage cutoff feature from you speed controller.

[Ravenwoods]

Thanks for the replies. I do not think the car has been run for at least 18 years. The people who gave it to me lived in their house for 18 years before they just moved to Arizona. Their son, whose car it was, has been out of their house maybe longer. So the car has been sitting around. I have no idea whether he raced it or not, but kind of doubt it. I'll find out. I have no idea about the gearing.

[Ravenwoods]

I assume the car has an electronic speed control? If so it is probably thermalling and shutting down, have you checked how hot it gets? You should be able to touch the motor and hold it for at least 5 seconds. What motor is it

Is the drivetrain free? If it had been sitting a long time the grease can dry up and make the gearbox tight. If he was racing it it would probably be geared for racing which is 5 minutes, so running it for 15-20 would be at three times longer.

Try a couple of teeth smaller on the
pinion and see how you go.

I have no idea if it has a electronic speed control. Would an old car from the 80s have that? How do I find out if it has an electronic speed control?

[mk-Zero]

If its an electronic speed control it will look like a rectangular box with wires that come out of it and go the the motor, the battery, and the receiver, like this


. If its a mechanical speed control it will look something like this


If the car hasn't been touched in as long as you think it wouldnt be for the problem I said about the speed control shutting the motor off at a certain voltage, I don't believe that older speed controls made for NiCads had that feature. In that case it probably is overheating. Pull the gear off the motor or loosen the two screws that hold the motor to the mounting plate and move the motor so the gears done mesh. Then see how easily the rear wheels spin. They should spin without too much resistance.

[Ravenwoods]

If its an electronic speed control it will look like a rectangular box with wires that come out of it and go the the motor, the battery, and the receiver, like this


. If its a mechanical speed control it will look something like this


If the car hasn't been touched in as long as you think it wouldnt be for the problem I said about the speed control shutting the motor off at a certain voltage, I don't believe that older speed controls made for NiCads had that feature. In that case it probably is overheating. Pull the gear off the motor or loosen the two screws that hold the motor to the mounting plate and move the motor so the gears done mesh. Then see how easily the rear wheels spin. They should spin without too much resistance.

I just took the body off the car and it does have a Novak Tempfet Speed control. Yesterday evening I attached my gps to the car and tested it in a paved parking lot. GPS said the car got up to 18.4 mph.

Later on I ran the car at just moderate speeds for 15-20 minutes without the motor getting excessively hot. Eventually the battery began to weaken.

I'll check on the gears to see how well they spin later on.

I just found instructions for the Novak speed control online. I've followed the directions about adjusting the neutral and speed controls.

I think there is some problem somewhere. The red LED light sometimes flicker indicating some problem. With the motor reconnected and the Futaba controller off, if I turn the car on, the motor comes on for an instant and spins the wheels. Is that normal behavior?

When I turn on the Futaba controller the motor will intermittently come on and move the car an inch or so and then stop.

The Novak instructions mention a "throttle reversing switch." There is a switch on the Futaba Attach controller (FP-T2NBL) to the left of the throttle that may be this throttle reversing switch. On the right side of the throttle is a sliding adjustment. If I move that adjustment upward then the car will start moving forward without touching the throttle. So what is the throttle reversing switch?

[integra22t]

the revers swich is there so if you push the throtal forward and the car goes forward you can flick the swich so when you pull the throtal back it goes forward

when you turn the car on it will always give a kick to let you know the car is on

just unplug the motor and set the speed control using the novak manual and plug it back in

other than that check the car over for any binding and you should be good .. do you know what your geared at ? pinion and spur ?

[Ravenwoods]

the revers swich is there so if you push the throtal forward and the car goes forward you can flick the swich so when you pull the throtal back it goes forward

when you turn the car on it will always give a kick to let you know the car is on

just unplug the motor and set the speed control using the novak manual and plug it back in

other than that check the car over for any binding and you should be good .. do you know what your geared at ? pinion and spur ?

I have no idea what the car is geared at or pinion and spur. I got an email from the guy who gave it to me. He said his son never raced the cars. He built several when he was growing up and this one was his last before he lost interest in them. So he estimates the car has been idle for 20 years or more and was not used a lot after his son built it. So it is not likely it was setup gear wise for racing.

[Kyoshojoe]

1800mah is a pretty small battery. 15 to 20 minutes seems about right to me.

Brushed motor setups are not very efficient to begin with and about half the power goes to heat. If you are running a lower turn motor it will pull more current and drain the battery even faster. The fact you are using an old esc with no voltage cutoff, it will generally pull the voltage down below a safe operating level which will up the current flow through the esc to compensate and maintain output wattage, which in turn means more heat. also as the motor and esc get hotter, the internal resistance goes up and it increases its inefficiency.

If your daughter is continuing to try and drive the car with the voltage dropping below operating threshold the motor will strain and will stop being able to move the car which in turn makes the windings just become heating elements and may char the com or melt the windings. If the comm is dirty or the drivetrain has friction it will generate more heat and not turn as smoothly. remember a brushed motor relies on air flow through and over the can and dissipation through the surrounding magnets to cool the rotor and once it stops moving it just heats up. going to a lower gear should help reduce the heat build up but its an issue of how fast the surrounding air can wick away the heat. basically a balance between heat genration and heat-sinking. you should always stop driving the car as soon as it shows a substantial or noticeable drop in acceleration. I hope im explaining this right and it helps.