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Van Aelst Jozef
9.December.2008, 15:58
Hello, have a question. Sorry for the English language but have tried it in German however without succes.

Have a cat with 2 electro motors, each with his own brushless controller and lipo pack. Before each controller is a liposaver installed. Input of both savers is connected via an Y-cable to the throttle output of the receiver.
If one lipo cel of a pack drops below the critical level, the corresponding controller will be put in a 30 % mode(for instance) of maximum level.
But the other motor is still in the normal ( max. voltage) mode.
The cat will go in a curve or make a sharp spin? Perhaps with a blow-over as result.

Can I slow down both controllers so that speed of the cat decrease without loosing rudder control?

How is a good protection done by a 2 motor boat?

Thanks for any answer. Please feel free to answer in your own language also.

Happy boating.

Jef from a small Belgium.

9.December.2008, 16:26
Simply change the sequence of components:

Actual: Rx ==> Y-cable ==> Supervisor A/B ==> Controller A/B
New: Rx ==> Supervisor A ==> Supervisor B ==> Y-cable ==> Controller A/B

Whenever one of the supervisor circuitries limits the throttle, both controllers are similarly affected

Van Aelst Jozef
9.December.2008, 18:13
Mist, thanks.
However have doubts about this solution.
Output of the supervisory module is a puls with a width between 1.2 and 1.8 msec. Suppose by full speed -->1.8msec. When the other supervisory module is activated (one lipocel low) the pulse width goes to (for instance) 1.4msec.
You can not add these two pulses with the Y cable because they have a different length.

Thanks for any sugestion.

9.December.2008, 18:48
Any output of a supervisor module is exactly equivalent (undisturbed, untouched, unmodified, ...) to the input, as long as there is no need for safety interaction. As soon as one of the supervisors (does not matter which) starts to limit the throttle, from the other's point of view this looks as if YOU have reduced throttle and both controllers work on the reduced throttle - that's the point.

Van Aelst Jozef
9.December.2008, 20:12
Michael thanks.

The supervisory module is in fact than transparant from any signals coming from the input ( Rx or the output from first supervisory modele) going to the output.
Only if action is required via a low lipo battery input signal --> the output gives the generated reduced pulse width so that both controllers can slow down.
Is my understanding correctly?.

9.December.2008, 20:54
Yes, it is.