Author Topic: Regeneration: a realistic source of electricity or just a gimmicky bonus?  (Read 8330 times)

Offline Pontus

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    • Grinde 19
I have the following setup.

  • Fin keeld sail boat @ 4 Tonnes that sails u to 7 knots in god winds
  • 10 kW water cooled BLDC motor @ 48 V mounted directly to propeller shaft (no reduction gears)
  • Fixed 3-bladed propeller 14" x 10"

During some recent sea trials I had some time to test out the re-gen feature of the VEC-500.

As mentioned above, our motor is directly mount to the propeller shaft, which is not optimal. This is up for rebuild this winter but I would nevertheless raise this topic.

The VEC-500 has two ways (as I know of) of controlling regenerative breaking. EBS Auto-mode and the connecting a break switch to the blue & white wire.

EBS Auto-mode
At first I left the default values, only flipping the enabled setting. This didn't produced any charging at all. I then set the charge voltage to 60 and limited the current to 10 A. As for "Auto_mode_speed (rpm)" I tried 60, 120, 180 and 240 rpm all with the same result - no charge.

Manual brake
Connecting the brake wire did seem to work. The controller started beeping 15 beeps in a constant loop. But the charging power was only around 30 watts while sailing in + 6 Knots.

RPM
Since our current setup uses a motor directly mounted to the propeller shaft the motor RPM is significantly lower than the rated value. This of course also applies during re-gen. So I expect better result after a rebuild of the transmission to a 1:2,6 belt reduction.


I do however have some questions which will determine if it's even worth aiming for re-gen.

Reasonable output Although our first test in now way indicative of an expected output I'm eager to hear of others in the forum, what power you have been able to get. At what speeds, boat size and propellers. Please share!

15 beep Is there way to disable the beep? Since our installation is in a sailboat, with very little background noise, a constant beeping from the controller is more or less not an option.

EBS Auto-mode Is there anyone in the forum who have got this to work on a sailing boat? I realize that the motor - and the re-gen - is aimed for land based vehicles using a tradition pedal throttle. In our case we have a boat throttle with zero in upwards (12 o'clock)-position, 9-o´clock for full throttle forward and 3-o´clock for full throttle backward. As of my understanding the auto EBS will activate when throttle signal turns 0, which makes sense in car. But since our throttle gives 2,5 V in standstill and 0 V in full reverse, using the throttle mode to Hyperbola. Either this will never work, or I have simply set something up the wrong way.

Starting the motor when its coasting
During harbor maneuvers, when giving the boat a short but powerful push using the motor and then immediately going back to 0 throttle, the boat glides in the water causing the propeller and motor to coast along very very slowly. During this coasting the throttle becomes unresponsive, in both forward and backward. If I do grab the shaft by hand causing it to stop, I'm then able to give throttle.

Any comments or sharing of experience is deeply appreciated.
Follow along my electric conversion of a 4 ton Danish sail boat. Grinde 19