Zippkits jae 21fe v2 outrigger_wood kit build

[sammyha]

Here's the Disaster at Drummond run when it hit thermal shutdown. Ripple versus lowest voltage is even worse. For percentage I'm dividing the ripple by the low voltage(sag) reading if that's correct. So, 7.12 ? 18.2=39.1%

Oof! No wonder it failed, right?



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[LibertyMKiii]

Here's the Disaster at Drummond run when it hit thermal shutdown. Ripple versus lowest voltage is even worse. For percentage I'm dividing the ripple by the low voltage(sag) reading if that's correct. So, 7.12 ? 18.2=39.1%

Oof! No wonder it failed, right?



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Hi Sam,
When looking at data logs you need to compare the data at that moment. (instead of the peak here and the low over here that occurred at another time.)
The mouse pointer black line which is your top row of data is that moment of time where your mouse is pointed. (I am sure you know that part)

No doubt about it the MX8s suffers from ripple voltage issues and lacks capacitance to suppress those oscillations. For lighter loads it seems to be a non issue, but when doing speed runs and pushing the system to extremes an external capacitor pack can help extend the life of the ESC.

When I record data from my runs I look at peaks during acceleration and then record specifics that occurred at peak rpm. That point normally should be at the end of the run when you let off the throttle.
You want to record what RPMs you reach Amperage it took to reach that speed, temps, and final voltage. This should help you analyze different batteries and props for the setup.

You are doing great and don't seem to need much input here, but if you ever have questions on the logs feel free to reach out.

If you have not done this already it solves the issue of zooming in and getting data values cut off.
View > Graph Zoom > Vertical Axis Locked

[sammyha]

I gotcha. Here's the 122 mph run with mouse aligned at ripple peak and corresponding voltage. Still too high but better at 5.87 ? 32.1=18.59%

And next the Disaster at Drummond run being 7.12 ? 32.8=21.7%

Right? One close to and one over double the max ripple of 10%?

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[LibertyMKiii]

Yes that looks correct.
I found 8,000 uF is a good amount for an external capacitor pack in most cases. The big challenge is what can fit inside the hull.
I used Panasonic low ESR 35v caps for DIY cap-packs. I have run as much as 21,000 uF in an RC car.

[sammyha]

More interesting info, I saved the Data Log when I tested the SMC 6s lipos. The HCL/HV and the SRD 5300 mAh lipos. They were at 19.8% and 17.2% ripple to voltage respectively.

Can I conclude those SMC lipos are pushing some serious power, and I'm stressing the electronics pretty hard on that setup with the Hydra X too?

That was with the 1921 prop, but the same setup that I ran the boat on 8s. I had it set wetter to stay down. Just swapped in the 6s lipos and made those two runs.

With the curved turn fin loosened up I ran 114 mph on the 6s SRD lipo before.

I can see how this can become a worm hole to go down, lol

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[sammyha]

Yes that looks correct.
I found 8,000 uF is a good amount for an external capacitor pack in most cases. The big challenge is what can fit inside the hull.
I used Panasonic low ESR 35v caps for DIY cap-packs. I have run as much as 21,000 uF in an RC car.

Wow! 8000uf! Castle offers this for the Hydra X. It would fit in the 33, but not enough?



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[racerr73]

https://www.youtube.com/watch?v=kdkNX7RwEiQ

This is a good video explaining ripple current, and the 10% maximum ripple rule..

[sammyha]

Very good video, thank you

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[Bande1]

The etti 8s cap packs are nice and will fit. you can possibly parallel a couple of them.
https://www.offshoreelectrics.com/pr...d=etti-e035-lv

[jkflow]

8000uF is more than enough, I've built my own, and it's 6x470 (2800) and brings ripple down to ~ 1.5V. Only running 4S though and ~ 180A. You only need to be below 10%, rest is snakeoil.

On your graphs, turn on current as well, you can also add power out, but you only want to confirm that it reaches 100%, else you can turn that off.
As per above, just compare data where the mouse pointer is located.

On your 'disaster run' something else happened as voltage spiked down to zero, that is something anomalous and you had some connection issue. Could be a result of the very high ripple and subsequent overheating of the caps, but that is just a guess.

Build your own, just need capacitors and solder them in parallel, make sure you get the correct voltage, castle caps are 35V.
470 and 1000uF linked below. I used to solder them directly to the power leads but you can use bullets.

871-B41895A6477M000 B41895A6477M000 TDK Aluminum Electrolytic Capacitors - Radial Leaded US HTS:8532220020 ECCN:EAR99 COO:BR

https://www.mouser.com/ProductDetail/EPCOS-TDK/B41895A6477M000?qs=gvwIECp2jlloxrMHqdfiXQ%3D%3D 667-EEU-FS1H102L EEU-FS1H102L Panasonic Aluminum Electrolytic Capacitors - Radial Leaded US HTS:8532220020 ECCN:EAR99 COO:MY https://www.mouser.com/ProductDetail/Panasonic/EEU-FS1H102L?qs=gt1LBUVyoHmx69WFoLyEhA%3D%3D Picture shows 6x 470uF, plenty of room. I'f probably use 8 in your case. 20230926_091710.jpg

[sammyha]

The etti 8s cap packs are nice and will fit. you can possibly parallel a couple of them.
https://www.offshoreelectrics.com/pr...d=etti-e035-lv

Is that a typo at OSE website? Says for 7s max, but rated for 35 volts.

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[sammyha]

Thank you jkflow, all good info and much needed...

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[fweasel]

I build my own for the capacitance and voltage the application calls for. I use Rubycon ZLH 1000uF caps in parallel and solid copper rod. Pretty easy to do.

capbank.jpg

[sammyha]

I build my own for the capacitance and voltage the application calls for. I use Rubycon ZLH 1000uF caps in parallel and solid copper rod. Pretty easy to do.

[ATTACH=CONFIG]177944[/ATTACH]

Very nice. Thanks!

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[Bande1]

Is that a typo at OSE website? Says for 7s max, but rated for 35 volts.

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yeah. I got one of them, they're 8s for sure.