General ESC Theory Discussion

Yup, I understand how it would regulate braking force. What I don't understand is how it would increase the rate of magnetic flux generated by the magnets, and consequently increase the voltage potential across the motor windings enough for current to flow back into the battery pack...

[zeropointbug]

Originally Posted by Aragon

Yup, I understand how it would regulate braking force. What I don't understand is how it would increase the rate of magnetic flux generated by the magnets, and consequently increase the voltage potential across the motor windings enough for current to flow back into the battery pack...

Think average voltage, if you have a longer Pulse width when switching the short for braking, then you have a higher average voltage than a shorter pulse width. Correct me if I mistaken what you are talking about?

Originally Posted by zeropointbug

Think average voltage, if you have a longer Pulse width when switching the short for braking, then you have a higher average voltage than a shorter pulse width. Correct me if I mistaken what you are talking about?

Mmm, what I'm ultimately talking about is converting kinetic energy into electrical energy and storing it in the battery pack. An RC car in motion is in a state of stored kinetic energy, the magnitude of which is proportional to its momentum, and the source of which ultimately came from the electrical energy that the system took from the battery to accelerate the car to whatever velocity. If the object's motion is stopped, its kinetic energy is transferred elsewhere. The key is to transfer as much of that energy back into the battery pack.

But the problem as I see it is as I outlined in post #14. The voltage generated by the motor needs to be stepped up somehow in order to charge the battery...

[lutach]

I just did a little test just to see how it went. I ran my DPR in live mode and hooked it up to my MBX5T that is now equiped with a Schulze 18.97 and a 7XL motor. I gave it some throttle and let it go so it would freewheel and the graph stayed flat. I then gave it some throttle and hit the brakes and saw a little spike on the graph. Just to make sure I hooked the DPR to my BPP truck that has a Schulze 40.160 and Neu 1521/1Y. Gave it some throttle and let it freewheel and the graph stayed flat. Then I gave it some throttle and hit the brakes, same thing happened a little spike on the graph.

That's great. Are you able to see the direction of current flow in the graph? The DPR records in both directions, so that spike could be current drawn from the battery or current drawn by the battery...

Originally Posted by lutach

I just did a little test just to see how it went. I ran my DPR in live mode and hooked it up to my MBX5T that is now equiped with a Schulze 18.97 and a 7XL motor. I gave it some throttle and let it go so it would freewheel and the graph stayed flat. I then gave it some throttle and hit the brakes and saw a little spike on the graph. Just to make sure I hooked the DPR to my BPP truck that has a Schulze 40.160 and Neu 1521/1Y. Gave it some throttle and let it freewheel and the graph stayed flat. Then I gave it some throttle and hit the brakes, same thing happened a little spike on the graph.

[lutach]

Originally Posted by Aragon

That's great. Are you able to see the direction of current flow in the graph? The DPR records in both directions, so that spike could be current drawn from the battery or current drawn by the battery...

The spike was upwards so it actually went to the battery.

Originally Posted by lutach

The spike was upwards so it actually went to the battery.

Excellent! Do you plan to test it in driving? Braking at varying levels downhill would be interesting to see.

How much does the voltage spike?