Technical, Techniques, Hints, and Tips > BRUSHLESS Motors and Speed Controllers

Brushless Motor Problems - Stalling

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Davo:
(See also Sea Queen going Brushless in the Powerboat section)
My Sea Queen was fitted with a Tornado Thumper 3542/05 1250 kv and a NiMh 12v battery. All was running well but the Taymia connectors were not coping. On advice XT60 connectors were fitted all through (I am ok on soldering) and all seemed well on the 60amp ESC. On the water the boat went off ok but soon stalled. I could here the ESC reset and set off again. Motor slowed and stalled.
Thinking the ESC was now the weak point I fitted a water cooled Hobbyking 120amp ESC. On the water the same thing again, motor just fades away. ESC resets and the same happens again.
On the bench, applying power, the motor revs up but then dies, even with throttle at max. Same in reverse. At neutral the ESC resets and the same thing happens. Both ESCs are set up with their programming cards.
So I bought a new 3548/05 900kv Tornado Thumper motor and fitted that. Same thing happens. Battery is 100% and neither escape makes any difference. Even plugging the battery direct to the ESC (no fuse in circuit) the same thing happens. The RX is on its own power. The TX has new batteries.
I am pretty sure all soldered joints are sound and so I am seeking any advice that might solve the problem. The XT60 connector replacements are the only real change in the system. Could it be a bad joint in the system failing under load?
Any thoughts folks?
David.

gra2:
Hi David it could be that the Nimh battery cannot cope with the power drain of the brushless motor.
May need a Lipo battery that will cope.

I have had this experience when trying a gell cell battery with a brushless motor when you need the power the battery cannot cope and stalls.

Graham

Fastfaz:
  I am no brushless expert but this might change your thinking after the last post re gel cell batteries. I have a twin screw Maltby tug running twin 70mm Graupner schottle drives and a bow thruster, the esc's are matched to the brushless motors 30 amp Mtronics, bow thruster 14k motor with a P98 (same power both directions) this all runs from a 14ah sealed lead acid gel cell. This tug will pull you in a rowing boat and the battery lasts all day in towing comps. I can only speak from experience with gel cells and Nimh's but it seems weird that a battery would cause this especially if its fairly new and fully charged. I have had experience of batteries appearing fully charged (13/14 volts showing) then as soon as they go under load out comes the white flag!
      I hope you get it sorted soon,good luck.
                Cheers, Pete.

john44:
Hi David,
You say the Rx has its own power supply, did you remove the red wire from the esc?
Rx plug.
If not that could be your problem because the Rx will be receiving 2 supplies from
Both batteries.


John

Andyn:

--- Quote from: gra2 on July 29, 2018, 01:41:11 pm ---Hi David it could be that the Nimh battery cannot cope with the power drain of the brushless motor.
May need a Lipo battery that will cope.

--- End quote ---
My money is on this. Is your esc currently set up to be expecting a LiPo? I've seen it too many times that an esc is expecting the higher voltage and when the voltage drops under load from a NiMh it goes below the LiPo voltage cutoff range.

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