How to determine amp rating ?

[Tat2]

Originally Posted by ta_man

When I see people asking those kinds of questions, especially people who do not know that the 200A rating of a VLX ESC is a bogus number, I think they are trying get an answer to a question that cannot be answered using the information they seek. They are asking those questions because they do not know the right question[s] to ask. (Not dissing your friend: most all of us were in that boat at some time or other. I certainly was.)

Like I said, I'm just the messenger.

Originally Posted by ta_man

Your friend wants a motor for his rustler. He doesn't need to calculate amp rating from motor parameters to pick out a motor. The reason I say your friend doesn't need that information (doesn't need - he still might want it, but that's not the same thing) is because he's not going to run any motor appropriate for a Rustler at max continuous rating.

I asked him further about what he's trying to do and he apparently wants to test the limitations of the VXL-3S before dropping a MMM into his Rusty. Which means that he wants to run a motor that many might consider inappropriate for a Rustler. This is what he e-mailed me: "...thanks. Being able to use this calculation to get in the "ballpark" will at least help to narrow it down a little. I wonder how Traxxas came to the amperage draw of the vxl, since it is used in more than one vehicle, none weighing the same, and all come stock with different gearing? Same with the vxl3s esc, according to Traxxas it's rated for multiple times what the motor draws, so a guy would think that it would never come close to having heat problems using th vxl motor, but I've heard of guys going thermal on the esc using the vxl motor, which should mean that they would have had to come close to the limits of the esc. Lol. What was Traxxas's theory behind having an esc that is overkill for the motor? That's kind of what I want to find out by buying another motor. I would like to see if the vxl3s can really do what it says it can do. I am planning to switch over to a castle mmm powered setup, but I want to explore the "supposed" capabilities of the vxl3s esc before I swap it out."
I'm still not entirely sure why he wants to do this, but it's not my place to question what he, or anyone else wants to do with their vehicle(s).

Originally Posted by ta_man

Maybe if I was trying for RC speed records I might need to know that (but not for a Rustler). But for anything a Rustler is useful for, you don't need that infiormation, [Opinion alert!:]nor will it help you with a decision.

I kind of get the feeling from talking to him that, somewhere down the road, this is going to end up being all about the speed.

Originally Posted by ta_man

Other people may have a different take on the opinions expressed above, so don't consider them absolutes.

All opinions are welcome. Thx for the input.