Need Help: Two blown motors in less than a month
#1
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I'm new to Hobby RC cars and I'm getting frustrated and need help. I purchased a Redcat Racing Blackout XTE less than a month ago thinking it would be a good starter car to learn on. I've been enjoying the car and my kid loves it, but so far I've blown two motors in less than a month which seems excessive. I'm not sure if I'm mishandling the car or just asking too much of it. But I either need to make this thing more reliable or return it and save up for something better that won't break this often.
So far the original 16T brushed motor that came with the car and a Traxxas 3785 Titan 550 each lasted barely a week, maybe an hour of total runtime each. They both ran very hot while they were working but I expected that. The car has a heat-sink to cover the motor but no active cooling. I ran the Traxxas motor through a dry break-in as I've seen recommended and lubricated it before installing. The original motor blew while I was still running the original 3000mAh NiMH battery and the Traxxas blew while running a Zeee 7.4V 80C 5200mAh 2S Lipo Battery which is supported by the current ESC. And yes I swapped the jumpers when I started running the LIPO battery so the ESC was set to the proper mode. The Traxxas had a puff of white smoke come out of it when it died so I was a little concerned that the battery was too much but the ESC still works as does the steering servo. I've mostly just been running the car in fairly short grass, a paved driveway and on some gravel roads. I was running the car on a sandy beach when the Traxxas motor died. I never ran the car for more than 10 minutes at a time as that was about as long as the batteries would last. And I made sure to let the motor cool off before swapping batteries and running it again. The motor would heat up to the point where the chassis itself was hot to the touch. I suspect that is normal behavior but wanted to mention in case it's not. I've rolled the car plenty and had a few crashes but nothing else on the car has broken besides the motor.
At this point I'm thinking a Brushless system is the way to go but I don't want to spend $100 on a new ESC/Brushless motor if I'm going to keep blowing motors every hour. With the Traxxas I was even trying to take it easy and not go WOT very often but that didn't seem to help. So I'm hoping someone can either recommend a brushed motor that will last longer than an hour, or a brushless system that won't break the bank but will be able to handle what I'm doing with the car and be somewhat reliable. I could see maybe wearing out a motor after a few months of heavy use, but not one a week.
Any advice would be greatly appreciated, thank you.
So far the original 16T brushed motor that came with the car and a Traxxas 3785 Titan 550 each lasted barely a week, maybe an hour of total runtime each. They both ran very hot while they were working but I expected that. The car has a heat-sink to cover the motor but no active cooling. I ran the Traxxas motor through a dry break-in as I've seen recommended and lubricated it before installing. The original motor blew while I was still running the original 3000mAh NiMH battery and the Traxxas blew while running a Zeee 7.4V 80C 5200mAh 2S Lipo Battery which is supported by the current ESC. And yes I swapped the jumpers when I started running the LIPO battery so the ESC was set to the proper mode. The Traxxas had a puff of white smoke come out of it when it died so I was a little concerned that the battery was too much but the ESC still works as does the steering servo. I've mostly just been running the car in fairly short grass, a paved driveway and on some gravel roads. I was running the car on a sandy beach when the Traxxas motor died. I never ran the car for more than 10 minutes at a time as that was about as long as the batteries would last. And I made sure to let the motor cool off before swapping batteries and running it again. The motor would heat up to the point where the chassis itself was hot to the touch. I suspect that is normal behavior but wanted to mention in case it's not. I've rolled the car plenty and had a few crashes but nothing else on the car has broken besides the motor.
At this point I'm thinking a Brushless system is the way to go but I don't want to spend $100 on a new ESC/Brushless motor if I'm going to keep blowing motors every hour. With the Traxxas I was even trying to take it easy and not go WOT very often but that didn't seem to help. So I'm hoping someone can either recommend a brushed motor that will last longer than an hour, or a brushless system that won't break the bank but will be able to handle what I'm doing with the car and be somewhat reliable. I could see maybe wearing out a motor after a few months of heavy use, but not one a week.
Any advice would be greatly appreciated, thank you.
#2

It's abnormal for motors to run that hot. There's something overloading them.
When you loosen or remove the motor, does the drivetrain run smoothly, with no binding? Maybe there's a rock or twig jammed in an outdrive or drive shaft somewhere?
The other thing to check is that the gear mesh between the small motor pinion gear and the larger spur gear is not too tight. It should have a bit of play between the gear mesh, but not so much that you risk stripping it. The old rule of thumb is to tighten them together with a thinnish piece of paper between them. Then, when you remove the paper, it should be about perfect.
If you're running at lot at full throttle in the grass, that is a heavy load too. The motor will be warm or even mildly hot to the touch, but it should not be hot enough that it immediately would burn you. If you drive it around on the street, does it still get hot? (that's easy duty)
When you loosen or remove the motor, does the drivetrain run smoothly, with no binding? Maybe there's a rock or twig jammed in an outdrive or drive shaft somewhere?
The other thing to check is that the gear mesh between the small motor pinion gear and the larger spur gear is not too tight. It should have a bit of play between the gear mesh, but not so much that you risk stripping it. The old rule of thumb is to tighten them together with a thinnish piece of paper between them. Then, when you remove the paper, it should be about perfect.
If you're running at lot at full throttle in the grass, that is a heavy load too. The motor will be warm or even mildly hot to the touch, but it should not be hot enough that it immediately would burn you. If you drive it around on the street, does it still get hot? (that's easy duty)
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I'll have to pull the car apart again to see if I notice any binding. I didn't notice any the last time I had it apart. The chassis would be very warm, to the point where when if I touched it I would not want to hold that part for very long. And yes, even on the driveway it would get pretty hot.
#4

I'll have to pull the car apart again to see if I notice any binding. I didn't notice any the last time I had it apart. The chassis would be very warm, to the point where when if I touched it I would not want to hold that part for very long. And yes, even on the driveway it would get pretty hot.
You don't have to take the whole car apart, just get the motor out of the drive train, turn things by hand, and see.
#5

If it makes you feel any better, three years ago I tried to return to the early years of my RCing adventures with brushed motors...was not good. Started out okay, but then quickly went south. Temps would skyrocket after five to six minutes no matter what gearing sweet spot I was chasing.
After trying to track down any binding, and you coming up with nothing, I'd think about getting a 550 size brushless motor for your 4wd truck. A longer can motor will generally give you more torque...something that a Blackout monster truck needs. Thankfully, Redcat uses .8 Mod gears (32 pitch compatible) on the Blackout, and a lot of longer can motors use 5mm shafts. Finding a pinion gear that fits on a 5mm motor shaft will not be an issue.
After trying to track down any binding, and you coming up with nothing, I'd think about getting a 550 size brushless motor for your 4wd truck. A longer can motor will generally give you more torque...something that a Blackout monster truck needs. Thankfully, Redcat uses .8 Mod gears (32 pitch compatible) on the Blackout, and a lot of longer can motors use 5mm shafts. Finding a pinion gear that fits on a 5mm motor shaft will not be an issue.
#6
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At this point I'm considering whether I should just return the car to Amazon and then buy something that has a brushless motor. The cost would be about the same and perhaps I could get something with a better drive-train.
Last edited by baron164; 07-03-2020 at 06:19 PM.
#7

The car is used and damaged now. I wouldn't take it back if I were the vendor...
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