Brushless Briefing :)

[elty19]

I've stopped playing Elect Cars for awhile and I need to get updated on the latest technology! When I last played, a 12 Turn motor was good and an 8 turn was insane... now with all the brushless stuff... I'm lost. How do you rate those things? the motors/ESCs? what's a good min to start with? Thinking of converting my old RC10 T3 to brushless... ;)

[Rcaddict]

I'll use mamba max as example here as I have 2 of them. Brush motor uses turn to indicate their speed, but not exactly the rpm. whereby brushless use kv. take the mamba max motor 5700kv as example. 5700 rpm per volt. how accurate is this number I'm not sure, some manufacturer rate their motor with load, some don't. If I'm not mistaken mamba max motor was rated at 10% load (whatever this 10% is, is beyond me haha).

Anyway if you're using 7.2v batt, 5700 x 7.2v = 41,040 rpm. So from here you can do the math and estimate how fast is brushless as compare to brush. 5700kv can be geared to be similar speed to 12t brushed.

I'll take a brush 6t motor comparing to my other mamba max motor of 7700kv. on the same car , same gear ratio, same batt,the 6t clocked very close to 50mph, whereby 7700 clocked around 50mph.The diffrence is, brushless runs cooler, more forgiving on the current drawn on the batt, and longer run time and u can gear even higher

usually brushless motor will have the rated current stated. And a general rule of thumb is, get an esc that has higher rated continuous current than the motor. That way you can really push the limit of the motor without causing ur esc to thermal. And usually esc with higher current rates is more expensive. Most car motors are rated maximum of 65,000 rpm. so I can use 11.1v on my 5700kv, but only 7.4v on my 7700kv. Another thing is, a motor with lower kv and higher cell count will run more efficiently than a high kv with low cell count. 1st combination lets u have greated gear ratio range, esc not as stressed/hot and higher torque. 2nd combi is the opposite. oh, its best to use lipo batts because brushless can pull lots of current, nimh can give u lots of cogging after a while enjoy!

[elty19]

thanks!

wow! thanks for the info man!! a 5000KV is just about equivalent to 12T? I thought it would be much more powerful than 12T... was thinking of getting the sidewinder combo.. still considering!

[Rcaddict]

well, to me 5700kv feels like 12t, some say it feels like 10t... anyway, torque wise i think brushless is much better.have fun, castle products are great imo