ESC32 Q&A

Info and Discussion about the ESC32 hardware and software

ESC32 Q&A

Postby JussiH » Wed Jun 27, 2012 10:32 am

Post any questions about ESC32 in this thread.
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Re: ESC32 Q&A

Postby jhoexp » Thu Jun 28, 2012 8:10 pm

Hi,
what's the max pwm frequency input and resolution for this ESC32?

Why the 2 rows of fets on both side of pcb? This way is more difficult to use an heatsink and find a good place for the esc.
Have you considered a more conventional layout and format, maybe longer but thinner, to fit better on smaller frames or on multirotors arms?

Anyway, nice product! Any latency comparison with other escs?
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Re: ESC32 Q&A

Postby JussiH » Fri Jun 29, 2012 2:22 am

jhoexp wrote:Hi,
what's the max pwm frequency input and resolution for this ESC32?

Why the 2 rows of fets on both side of pcb? This way is more difficult to use an heatsink and find a good place for the esc.
Have you considered a more conventional layout and format, maybe longer but thinner, to fit better on smaller frames or on multirotors arms?

Anyway, nice product! Any latency comparison with other escs?


Thanks!

Resolution is 1800 steps @ 20Khz (default) and 750 steps at 48Khz.

The 2r1 design is a necessary compromise to keep the current paths as short and wide as possible, and to seperate the power and logic groundplanes to shield the logic from ripple currents and spikes that can knock out the MCU or lock it out.

The previous 1r5 version was more similar to a traditional layout, but had problems with >3S and high current spikes, so it was redesigned to make sure that 4 and 5S and big motors with large current spikes would still work properly without locking up and cooking your motors.

We are working on making some heatsinks for this revision. But adding a piece of alu plate on each Fet row would probably be a good beginning. With all the CNC machines around, I am sure it wont take long for the community to come up with some good candidates for heatsinks. Still, the best thing you can do is to place ESCs in the propwash - the windchill will remove a lot of heat, even without a heatsink... but heat should not really become a problem before you begin to draw more than 10A continuously on each motor.

No latency comparisons at this time. We welcome if someone does it, but its not on our "todo-list" ;)
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Re: ESC32 Q&A

Postby LPR » Fri Jul 06, 2012 1:04 am

Bill
The octo I have that the AQ autopilot will go on has motors designed to 6s lipo batteries. After testing the motors with different batteries and props I find that 6s a123 batteries with 12" props instead of 10" props gives me the thrust I need for a successful octocopter.

The question is, do you think or know if it is safe to use the 6s A123 battery instead of 5s lipo?
The voltage for a 6s A123 is 19.8 and a 5s lipo is 18.5volts.

6 years ago I found out the hard way that too high a voltage can cause major damage. I used 5s A123 with a MK FC many times with no problem but when I connected a brand new A123 pack with a fresh charge I fried the board.

The maximum voltage on A123s is 3.6V for 21.6v. Lipos maximum voltage is 4.2V x 5 for 21volts.
So maximum voltage is only .6 Volts higher.

Larry
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Re: ESC32 Q&A

Postby bn999 » Fri Jul 06, 2012 4:01 am

If you are asking about ESC32, the max voltage the FET drivers are rated at is 20v. 5S can be as high as 21v for a short period of time. The DS of the FET drivers allows a little wiggle room, but we are already pushing it.
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Re: ESC32 Q&A

Postby LPR » Fri Jul 06, 2012 1:02 pm

bn999

Thanks for the information. If 20 volt is the maximum voltage then my A123 should be OK for powering the ESC32. For powering the AQ 6.6 I'll use a miniature step-up / step-down switching DC-DC converter like this one from Dimension Engineering.
http://www.dimensionengineering.com/pro ... volt-micro

Larry


bn999 wrote:If you are asking about ESC32, the max voltage the FET drivers are rated at is 20v. 5S can be as high as 21v for a short period of time. The DS of the FET drivers allows a little wiggle room, but we are already pushing it.
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Re: ESC32 Q&A

Postby LPR » Mon Jul 16, 2012 6:33 pm

I have 8 ESC32 wired in my octo and I'm using 5s lipos. All the ESCs are working but I'm looking for a better way to power the ESCs fets and the MCU. I power the ESC32s MCU with a UBEC and I know it will b e hard to always remember to connect the UBEC first and when the main power supply and then to reverse the process when disconnecting the power.
Does anyone see a simple solution?

Larry
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Re: ESC32 Q&A

Postby Kisssys » Mon Jul 16, 2012 8:45 pm

Hi Larry,

If you look on the FC board, each motor output positive pin has a small solder jumper that is not completed. If you complete that jumper you can power the ESC's from the FC board instead of your BEC.

The board makes some power adjustments for change in battery voltage, if you feed the FC board a regulated voltage it will not be able to correctly do that. I think you will need to make some code changes if it's not fed a normal Lipo battery. You could drop the voltage to the FC through 6 silicon diodes and then change the battery detection to follow the A123 battery profile applying a offset for the voltage dropped across the diodes. The AQ takes considerable effort to get running and your adding variables that no one has had experience with.

Good Luck
Steve
Steve
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Re: ESC32 Q&A

Postby LPR » Wed Jul 18, 2012 9:41 pm

Steve

I think the diodes will work.
I ordered the AQ board but Jussi will not be back till August so it will be a few more weeks till I have one.
A123 batteries have a very flat voltage output and often have a small voltage increase near the end of there charge.
For my project the A123 are a very necessary complication.
I have 5s lipos that I can use for calibration and test flying.

The voltage regulator on the FC is OK with 5s lipos right?
Should I use a few diodes to bring the voltage down for 5s lipos also?

Larry
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Re: ESC32 Q&A

Postby Kisssys » Thu Jul 19, 2012 1:27 am

Hi Larry,

Well a full Lipo is 4.23 volts that times 5 is 21.15 volts so your above the Recom regulators max input rating of 18 volts.
The voltage rating may be more towards power dissipation so it might work as long as the load on the 5 volts stays low. I personally would drop the Lipo voltage also just to make sure.

Their are other regulators of the same format that handle a higher voltage so if 5 cells becomes an issue maybe the board can use different regulators in the future.

Cheers
Steve
Steve
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