Mamba monster cogging
 

I have a converted Cen GST with a Mamba Monster ESC and am having a cogging issue.If the truck is stopped,it will not move unless I give it a tap with my foot.I dont have to move it hard,just a little tap does the trick.Once the truck starts though it goes like crazy.It has a ton of tourqe and runs about 35 mph.I am confused here.I thought if the gearing was so bad that I had to kick it to get it moving that there would be no tourqe.This truck wants to tear the rims right off of it.I am using a KB45-XL 700 KV motor,Mamba monster ESC,5s 20c Zippy lipo.I have a 66t spur gear and a 18t pinion.It has alot of tourqe and nothing seems to be getting hot.The battery gets slightly warm and that is it.Any suggestions?Thanks

Man, that surely isnt a lit of rpms, less that 14,000?

I Dont think its the Momba Monster!

Any idea what it is then?

Yeah,I had planned on running a different setup and then changed my mind.I had already purchased the motor though.I plan on changeing the motor and getting bigger batteries in the future.

Probably bad timing, how many poles do you have with your motor ?

The KB is a 2-pole motor in a 45mm can.

Then timing must be at 0

hi and thanks for the reply.I was thinking it may be a timing issue since there is plenty of torque.I will check to see that the timing is at 0.Any suggestions if that doesnt work?

More voltage or different motor.

Castle 1520 or 1717 motor ;) ;) ;)

0 timing, and more voltage (around 8S - 10S) should do wonders with that motor. Of course, gearing will have to be changed according to voltage and speed you wanna run

Like was said, the kv is way too low for 5s; only ~13000rpm. That setup would work if you were geared for around 10-15mph, but to get 35mph, you probably have a really high rollout ratio (geared tall) and the ESC is having a hard time to get the motor to spin fast enough to get a good rpm reading. Also, you are no doubt pulling quite a bit of current on start due to the tall gearing. You either need a higher kv motor, or run a different ESC and 10s (and then gear down to keep your 35mph speed).

Thanks again for the response.I will just get another motor then.I am on a tight budget right now so I am going to have to stick with HobbyCity motor for now.Think 1500 KV would be a good motor and just use a smaller pinion?

May be a little higher. Say around 1800Kv to 2000Kv for 5S

Thanks,I was wondering if it is safe to use the setup this way untill I get another motor?Will I ruin something?Nothing is getting hot and it seems really good other than the cogging in the beginning.All I have to do is tap the truck and it takes off like a rocket.I don't want to ruin anything though.

This is probably more explanation than you want, but when you gear up any system too high, the motor is effectively stalling. And when that happens, HUGE amounts of current can flow (well into the 1,000's of amps!) which can destroy batteries and ESCs. When an ESC is cogging, the motor isn't moving (or very little) and is essentially a stalled motor.

So, I don't think you should keep running it like this unless you gear WAYYY down, something like 15mph.

Try a timing at 0 first then us how its working !

Did you check your bullet connectors on the motor and ESC for bad solder joints.

I am going to check everything out tonight.I will set the timing at 0 and go from there.I am going to try a 6s lipo my friend has and see if that helps.I have a deans connector on the esc that I will re-solder also.Hopefully one of these things works.I saw a video from 93Formula that has this truck doing a standing backflip on 4s though and he is using the same center diff I am from the cen matrix with a mamba esc.I do believe mine would also do a standing backflip now if I locked the center diff.I will try to change the gearing like others have said if the other stuff doesn't work but I think if I gear it for more torque than it has now I will start breaking things.Driveshafts etc.

I just tested the timing at all of the timing options.It cogged at every setting.It seems though as long as the truck is moving in either forward or reverse it doesn't cogg.If I am running at 1 mph in reverse and give it slight forward throttle,it just goes forward without cogging.I did notice that if I move the pinion gear even slightly to turn the motor,my motor fan that is plugged into the reciever changes rpm's.If I do 1 full rotation with the pinion,the fan speeds up and slows down 2 times each.Just something I noticed.

Like BG stated, the motor is basically stalled at a stand still. More voltage, LOWER gearing, or different motor will help.

Thanks,I am going to try a 6s 5000mah 30c lipo my friend has and hopefully I get a better result.If not I am going to start to gear it down.I can't afford a new motor now so that will have to wait.Thanks to everyone for all the help.

Maybe there is another solution. Try to configure the start power at high on the MMM, its at low in the default setup. The timing must be at 0 for a 2 pole motor, so try it with 0 timing with high start power.