How to select ESC and BAT for a given motor?

[Migs]

Friends:

I have always wondered how to select the ESC and the battery for a given motor.
Can someone explain this please?

Thanks amigos, -Migs

[bigflex]

you basiclly just decide what speed and or torque you are wanting to run and go from there. If its a hot motor like a 17t or lower than you will want to make sure the esc can safely run that motor. If its a brushed crawler motor pretty much any esc on the market will work with it. If its a brushed puller motor than as long as the esc can ru n a 19t motor you will be ok. As for batteries. The esc will be your determaning factor on them. Alot of esc's out there are only good for 4-6 cell NiMh. If they will run that on the lipo end you will only be able to run 2c packs. If you want more juice than that your gonna have to get an esc that can handle more voltage. If you run a lipo on an esc that doesn't come with a lipo cutoff you will need to get an external cutoff or you will end up damaging your batteries. Theres alot of deciding factors other than these like features and brands and warranties, but this should get you started.

[Migs]

Hi Bigflex:

Thanks for the intro. Do you know where I would read up on all this? I think with what you gave me I have a basic concept, but I would really like to know well. What is the fundamental information that you take in a motor's specifications in order to select the ESC? Will the ESC also list these same parameters?

I would imagine that a motor has a peak wattage, and that this must somehow define a minimum ESC. If this is true, then how is this information expressed on both sides?

I have a Titan 12T 550 motor (12-turns). ("Titan 12T motors are intended for use in single motor and single battery pack applications, up to 8.4 volts." )

Migs

[JohnRobHolmes]

basically you have to do the research yourself. For crawling, you mostly worry about the battery and stall amp draw. More specifically you worry about the amp draw below the threshold of breaking parts. You can always get a bigger battery (runtime or discharge rate) than is needed. Also, as the voltage increases the stalling amp draw will increase too.

For example, let us take a 35t handwound motor. In a 2.2 shafty I know that a 1300 3 cell 25c lipo will cut it. Just barely, but for competition it works nicely. I can always use a bigger battery.

From experience I know that tlt axles will not take much more than 30 amps from the motor before the ring and pinion blows apart. Replace this and now the driveshafts or outer shafts become the weak point, and you can bury the throttle a bit more before parts break.

From experience I know that axial axles will take over 60 amps (same motor), but the driveshafts will blow apart around 40. Beef those up and now we are talking about some serious battery needed to keep up with what the motor can do.

With crawling it isn't so much a question of what the motor can do, it is more important what the rig will handle, and most important how you drive. Even a cheapo 55t can pull 500 amps if it is shorted and stalled. Of course it won't last long, but it is possible.


I have a collection of motor/battery recomendations around here somewhere. When I find it I will post it up. I have some on my site too, mixed in with the motors and batteries descriptions.

[Migs]

Thanks a bunch! I realize now that there is no short cut to figure this out. Perhaps before I have to set something up I'll post it to see if it makes sense. Or else ask for recommendations on the combination! Thanks again. -Migs