I am building a 3S freestyle micro and have a 15A aio laying around so I will be using that. 

I am looking at motors and have heard good things about Emax Eco motors, but looking at the spec table I'm confused. 

I believe that I have to have motors that will pull no more than 15A...looking on the website below, however, the tables show peak current at 10S, yet these motors are rated for 2-4s???   

https://emaxmodel.com/products/emax-eco-...g-rc-drone#

So if I look at the 3300KV model, it says 17.7A...but at 3S is that lower?

I feel very lost.  Any help is appreciated, thank you.

if the 17.7a are peak, it should work with 15a esc on 4s. what brand or model is your esc?

the ampdraw would be lower at 3s, around 13a peak

what eco motor did you aim?
the good things i heard about eco motors was all about the 5inch motors, i still prefer the highend motorline from emax on micromotors.. while the 5inch motors work and are half the price of a highend, its not a hige difference on micromotors. eco motors has a lower technology/manufacturing level.
i use the emax rs1306b 4000kv motors, they are pretty ok

Thank you - how are you coming to 13a peak on 3s? Just so I understand. And what does the 10S mean?

The AIO I am using is Fettec mini 15A. I was thinking of the Eco 1407 3300A or 4100A. A friend recommended the HGLRC 1407 3600KV motors - he runs a full size hero 8 on his micro at times, and says those motors run extremely well, although he runs it on 4S. Plus the HGLRC are currently $43 for 4 on Amazon so I am debating those as well.

thats just experience and what i would expect as max current, so lets making a bill:

the general rule is about rpm, as more rpm as more current. 4s is 1/4 more rpm: 17,7a / 4cell = 4.425a
4,425a x 3 = 13.275a
as lower cell count is always gives a littlebit higher current for the same trust, it needs a bit addition. lets say 0.735a ;-) it gives peak of 14a. im sure you will stay under 15a peak on 3s, but the current is also a tiny indicator for power, dont forget it will be slower and less powerfull on 3s.

(edit: there is another indicator about max power, if a motor does provide a very high max trust for its size, it also going to be inefficiency and produce heat and an unproportional current. while lower cell count does have a bit higher ampdraw for the same trust in general, it changes when we are going to ask for more than a motor like to provide, if it heats up next to an awesome performance.)


the rating of 15a is for 1106 up to an efficiency 1404 or 1306 motor on 3s. a powerfull 1406-1408 draws up to 20a.
while its only rated for 15a, fettec is quality stuff and i believe it can handle a peak current of 20a on a lightweight build... i dont see an issue regardless that rating.
anyway, 1106/1204/1206/1207/1303... will fit the esc rating perfectly and gives very nice lightweight builds, powerfull and efficiency .... if you dont have a reason like many 650mah-850mah batteries which would fit 140x motors, i would go for a lightweight sal motor 3inch.
the difference between them is a bit better topend on the bigger motors and better efficiency and durability on the smaller ones... both are awesome powerfull in regular flying rpms.

Wow, thank you for taking the time to explain all that!

I do have some 1303 5000kv motors laying around, maybe I will try those...

10S = 10 seconds
They are saying it is "peak" rating

The ESC rating is using good airflow, and is based on Rdson, and Tp.. the FET resistance when closed, and thus heat, and its package heat disipation rating.

Over the years ESC are marketed more "optimistically".
A 30A ESC made by Company A, can be branded as 40A by Company B. ie DarwinFPV.

A 15A AIO, almost always uses 2-N channel half bridge.
They are VERY susceptible to heat failure.
I have drawer of broken FC and most are 13A,15A,20A AIO FC.

I would not use anything bigger than 3" and 1204 with one of those.

darwinfpv is the best example, an eachine 30a esc rebranded with darwinfpv and rated for 40a xD customers are attracted by the 10a higher rating, thats the issue, that marketing works

What does it mean when it says active current limiting: 15A? I'm assuming that's protection?

I don't know much about KISS's ESC firmware (it's closed source - no one does) but it should do. Assuming it's the same as the BLHeli32 feature it should protect itself by biting down on the current draw if the motors start pulling too much.

limiting isnt truly what we like xD it wont help to protect the electronics in a crash, crashes are the most often situations where escs burnout.