Expert: Ken Myers - 6/23/2009

Question
Hi Ken,
I have a problem with one of my esc (I think) on a Twin Otter electric I am building.
The problem is when I pull the throttle stick up on the test bench, one of the motor is kind of lazy and do not start until I give more power... And when it starts, the other one is already running strong.
Can it be the esc? I soldered the red wires from the 2 escs going to the lipo battery together and the 2 black wires to a single Deans connector so I don't have to use a parallel connector. Does that se tup makes it impossible to program each esc? I checked the programing and it is set at soft start, but is it possible that the 2 escs are NOT actually programmed the same way?
It seems also that the motor that starts after the other does not have the same throttle power curve.
I am lost.
Thanls.
Philippe

Answer
Hi Philippe,

Wow, I just posted some information on this problem in the July Ampeer electric flight newsletter.  It was just posted about an hour ago.  It is the first article, "Setting Up and Syncing Twins".

You'll find the July 2009 issue of the Ampeer here:
http://homepage.mac.com/kmyersefo/

A link to this month's issue is near the top of the page.

You didn't mention whether you are using the built-in BEC's of the ESCs.  You really shouldn't with a twin, as you'll have too many ESCs and servos for the linear BEC to handle, and if you are using them, only one should have the red wire in "servo" line connected to the receiver.  The other needs to be clipped or separated somehow.

As I said, you should be using a separate receiver pack or a separate switching BEC unit.

Hope this helps,
Ken