CRZMONK3

Simple and easy question, can I use one speed controller running two size 180 motors or will I need one speed controller per motor? Also how will this affect my battery life?

ESC is a 7amp up to 280 with a 6 or 7 cell 400mAh 2/3AAA battery.
Thanks

Wright Flyer

As long as they're brushed motors you can run any number of motor from the ESC as long as you don't exceed it's current limit and the motors are going to get the right number of volts. If you have two motors on a single ESC there's a couple of ways it could be wired. Let's say a 180 motor is pulling 2A and runs on 8.4V (7 cell). You could wire the two motors in parallel to the single ESC and both would still get 8.4V but the combination would now be pulling double the amps (4A) through the ESC (in your case, with a 7A ESC this should be fine). Alternatively you could (if you had a setup getting near the current limit of your ESC) wire the motors in series. In this case the two 180 motor combo would be pulling that same 2A through the ESC but the problem is that each motor would only see half the voltage - 4.2V so you'd have to double up to 14 cells so the ESC sees 16.8V and the two motors get 8.4V - in such a series setup you have to be sure the ESC is capable of the increased voltage. This is especially true if it has a BEC circuit providing power to the receiver and servos as it's far more difficult (read heat!!) for it to drop 16.8V to 5V than it is to go from 8.V to 5V. If you had even more motors - four say, then you could have them in series pairs wired in parallel to the ESC, all four in series or all four in parallel.

Cliff

CRZMONK3

i will try both setups and will see how it will work, thanks for the info.

CRZMONK3

Thanks again for the incredible help and info “Wright Flyer” Now, will I have to use a special ESC if I will be using Li-poly battery with my brushed motors? and Also I was looking at some of the Multiplex 280 motor with a max current efficiency of 2 Amps
http://www.hobbypeople.net/gallery/240010.asp
This should work the same with my 7Amp ESC?

Thanks in advance.
Crzpete

Wright Flyer

Crzpete,

It's funny but you don't see Speed 280 motors used very often these days. Folks get much better results with either geared 180 or 300 motors (GWS have made a major industry out of just this!!). You may want to rethink what you're planning cos for small stuff a couple of GWS IPS DX (proably "A" gearing) are a popular choice while GWS EPC 300 (probably "c" or "d" ) are popular on slightly bigger park flyers. The IPS run about 2A while the EPS can be anywhere from 4-8A for each motor/gearbox

As for using special ESC with Lithium batteries this seems to be a popular fallacy. It's true that LiPo cell smust never be dropped below 3V in flight or the batteries could be seriously damaged. With this in mind there's all sorts of add-on "LiPo saver" circuits or new design ESCs that have LiPo mode where you say whether you are using 2, 3 or 4 cells and the ESC then makes sure the volts don't go below 6, 9 or 12V. But let's face it, in a properly propped/geared setup you are going to have lost any thrust to fly long before the batteriesd get near these voltage levels. An Astro Whattmeter is a useful gadget when first setting up to pick the right gearing and prop diam/pitch but after that I'd say the LiPo's would be pretty safe without fancy protection circuits.

'Course if you did something stupid like taking a "normal" setup and then putting on a prop with double the normal diameter or pitch and flew that you may have a pretty wild time for a few minutes before the batteries explode!

Cliff