brushless current draw?
 

just out of curiousity, if i upgrade my blade to brushless using this http://www.helidirect.com/product_in...oducts_id=1524 motor with 9t pinion, what Amp do i need for a esc? eflight recommend a 20amp for their 4100kv, some gone with 25, some even gone with 35A, what should be sufficient?

RE: brushless current draw?
 

i used to run a 25A esc until a few weeks ago, after i hooked up my wattmeter to my 4100kV w/8T and got 9A at full collective (+12 degrees pitch); this was at the battery, with a long can geared brushless tail spinning ~half speed, so the main motor was probably drawing closer to 6A. ever since i've been running a 10A esc to save weight.

RE: brushless current draw?
 

haha, thx, so even teh 20A is overkill:D what was the 4100kv's no low current draw? the motor above is 2.6A. just trying to get some states so that if i ever decide to go bl, i'll know what esc to get.

RE: brushless current draw?
 

opened up my manual and found this:
himax 2015 4100kV:
no load current = 0.80A
efficient operating current = 5-12A
recommended esc = 10A

looked a bit more and saw this:

himax 2015 3600kV:
no load current = 0.54A
efficient operating current = 3-8A
recommended esc = 8A

2.6A is a high no load current. don't know a whole lot about brushless terminology, but i guess higher no load current means more current is required to spin same RPM without a load. so i think lower no load current = higher efficiency, but not sure if things change a lot when the motor is loaded.[:o]

hope this helps.

RE: brushless current draw?
 

just found this link if your curious:

[link=http://davesrcflight.mysite.wanadoo-members.co.uk/frame_pages/electric_flight_frame4.htm]http://davesrcflight.mysite.wanadoo-members.co.uk/frame_pages/electric_flight_frame4.htm[/link]

i guess Rm (winding resistance) is also an important factor when comparing motors. that page explains a bit more about brushless theory and gives a few equations to go with it. may or may not help, but it's good info to know anyways. i found out i was wrong about no load current. apparently it's independent of rpm or voltage. interesting huh?

RE: brushless current draw?
 

hmmm...0.58 no load current?! that's pretty good, i've read somewhere else that even though no load resistance is independent of everything else, a lower no load current will usually make a better motor, the eflight's 4100 has a no load current 1A. i guess 2.6A is VERY high then... no wonder it's dat cheap:D thx, i was just trying to get some data.

RE: brushless current draw?
 

Chopperdudes,

I have the same motor on my CP Pro and use the Sonix 18A esc.

The motor runs cool to warm and the esc is barely warm after 8 minute flights. That motor has plenty of power with the 9t pinion. With my Futaba 6exh radio, I really have to lower the throttle curve. If I run the high end at 100 %, I'm pretty sure the head would explode. It also runs fine with the stock radio.