dual brushless circuit problem.

[earthwormjim]

Hi All.
Its me.
I am experiencing a problem...
I have 2 brushless speed controllers running from an 11.1v 240mah lipo.
I have both controllers wired up to the same rc channel.
Both motors run fine when run singly,but with both connected,they run upto about 25% throttle,then one stops.The other keeps going.
Am I asking too much from the one rc channel,or am I asking too much from the battery?
Any info,and suggestions on how to remedy the situation greatly appreciated,thanks.
Jim

[josh]

Are you combining both bec cable sets? Is it that the two BECs are competing, reducing the power output to the motors? You should have one red, one black and two whites to the channel, or just the whites if you are using the bec from another controller to power the reciever.

[earthwormjim]

I'm glad someone knows what they are doing.
Thanks Josh.

[earthwormjim]

OK. Re-wired,and situation is the same.
With a freshly charged battery,One motor accelerates all through the sticks movement,but the other motor only accelerates to half way,then decelerates the rest of the stick travel. I will swap the motors to use the different controllers to see whether it is the motor or controller.Also,I am getting less than a minute at full whack before the batteries are pretty much useless. Seems a bit extreme??
I was hoping for a little longer!!

[haz]

bigger battery
?

[josh]

What controllers/motors are you using? Might be better to run a larger controller and the motors in parallel off the same controller. Saying that I haven't a clue if that actually will work with brushless but I can't see why it shouldn't in a sensorless set up.

[Craig_Anto3]

how is the power being distributed between the boards?

[peterwaller]

You cant use two motors on one controller as they detect the spikes generated by the motor to measure its speed so two motors unless perfectly in sync will confuse the controller.
I think the battery is too small. Even if it is 30C it means it can only supply about 7.5 amps and depending on the motor one alone could take that even at 8.4v let alone 12.6 where it will be 1.5 times as high.
You might find that the controller that shuts down is set to 3 cells while the other is set for 2 cells so it shuts down at a much lower voltage.

[earthwormjim]

Thanks chaps. I guess the answer is a bigger battery. I might just adapt it for one motor,as the design doesnt specifically require 2 motors.Could be the simplest option,as I am seriously pushed for weight.

I might re-visit this in the future though.Cheers for the input.

[haz]

make it a walker!