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Takedown · 02.07.2008, 07:00 PM

Today I picked up some 330uf 50v capacitors from my electrical engineering class. I know its a little to high of voltage but they should work perfectly. The stock capacitors are 330uf 25v. Im most likely gonna drill out the back end of the VXL case so that the capacitors will come out the back end instead of being directly mounted to the board. I am still a little confused on what I should do to disable the over voltage cutoff. Im was told to do this.

"
Thinking about it a little, it probably has an ADC in there to detect overvoltage/undervoltage. Since they also have something of a LiPo low-voltage cutoff in LiPo mode. In this case what you would be looking for would be a voltage divider (2 high-value resistors in series) across the voltage input, with the output of the voltage divider going to maybe a small capacitor (other side to ground) and then to a pin of the microcontroller or another IC which you could identify as an ADC. Or if you can identify the micro, you can tell if that pin has a (potential) ADC mode. If this is the case it is a simple fix, just replace the high-end resistor on the voltage divider to create a different ratio and "fool" the ESC into thinking, say, 15V is really 9V. There are other ways to design it, but that's the cheapest and most convenient way (IMO) so I think it's what Traxxas would do, so I think that's what you'd be looking for -- two resistors in series attached across the input."

The VXL has two resistors on each input (+,-) Should I remove them and what should I install in place of them so that the ESC will think that it is running in proper voltage range?

All help is appreciated.

	(#3)
Takedown WARNING: May become violent. Offline Posts: 2,426 Join Date: Mar 2007 Location: Wisconsin	02.07.2008, 07:00 PM Today I picked up some 330uf 50v capacitors from my electrical engineering class. I know its a little to high of voltage but they should work perfectly. The stock capacitors are 330uf 25v. Im most likely gonna drill out the back end of the VXL case so that the capacitors will come out the back end instead of being directly mounted to the board. I am still a little confused on what I should do to disable the over voltage cutoff. Im was told to do this. " Thinking about it a little, it probably has an ADC in there to detect overvoltage/undervoltage. Since they also have something of a LiPo low-voltage cutoff in LiPo mode. In this case what you would be looking for would be a voltage divider (2 high-value resistors in series) across the voltage input, with the output of the voltage divider going to maybe a small capacitor (other side to ground) and then to a pin of the microcontroller or another IC which you could identify as an ADC. Or if you can identify the micro, you can tell if that pin has a (potential) ADC mode. If this is the case it is a simple fix, just replace the high-end resistor on the voltage divider to create a different ratio and "fool" the ESC into thinking, say, 15V is really 9V. There are other ways to design it, but that's the cheapest and most convenient way (IMO) so I think it's what Traxxas would do, so I think that's what you'd be looking for -- two resistors in series attached across the input." The VXL has two resistors on each input (+,-) Should I remove them and what should I install in place of them so that the ESC will think that it is running in proper voltage range? All help is appreciated.