Colorado winter build - ARC200 - flipsky 120kv - samsung 30q


Waterproof test with the bike valve and a air compressor! Saved me from multiple trips to the lake to test waterproofness of my box!

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Back on the water with light from the Colorado wildfires. Trying out the slingshot 84cm infinity foil. Efficient slower ride.

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Hello Brycej,

I ended up useing the same configuration than you, using an arc200 with a Flipsky 65110 120kv under 12s.
I used to have a 640kv with a gear box before the flipsky and I was doing well, have enough torque to fly quickly.
Yesterday was my first attempt with the flipsky + arc200 and never manage to fly. Everything works perfectly and is smooth but I have not enough torque to fly. I don’t know if it comes from the 12s, the Flipsky or the configuration of the arc200. Would you mind sharing your arc200 conf so that I could maybe correct something wrong ? Are you under 12s or 14s ?

Cheers,

Matt

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I’ll grab it next time I connect it up.

The biggest thing that helped me was bumping up the motor/phase current to 150A. I think the default was 50A which is way to low.

I have been experimenting with RPM mode, which I must not have something set up right because I am getting a less power in that mode. But Torque mode for me had worked welll.

Bryce

Thank you Brycej.
Indeed Torque mode seems to give better results and I already set the right parameter regarding the motor/phase current. I could maybe blame my lipos that are getting old and worn out, and don’t give enought power now.
Does anybody know what it does when lipo are dead ? I can still charge them quite easily…

Thank you !

Matt

The lipo will sag a lot more under load. Couple volts isn’t a problem at 12S, but >5V might be. If you pull the logs from the ARC200 you should be able to see how much it is doing that. A lipo (not li-ion) will also start to puff up a little and get hotter (internal resistance goes up so at high currents it generates more heat)

Thank you. Well I don’t manage to get up now and everything seems to be ok. I’m on 12s2p with 4x8000mah lipo.
Unfortunately I don’t have access to the USB cable and only use the bluetooth interface so that I don’t have access to log :frowning:
But I should see it in the telemetry…

RPM mode tries to get to a set RPM with minimal current and as a result doesn’t ever get the prop to the correct RPM with a direct drive motor.
Torque mode is a much better option for direct drive.

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Have you also set your battery current up to about 130A. If that is too low, then it will also prevent your phase currents from getting up to where they need to be…
Check your logs and see what your voltages are sagging to under power.

Crunch… Lakes have dropped like 5-10 feet depending on the reservoir. Was out aways from shore and hit a sandbar… Near where a couple other boats were puttering over… I guess I had a deeper draft.

Time to get the new board machined out and get rid of that windsurf conversion!

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Holy crap! Are you okay?

Hahaha yup, wasn’t even going that fast. Just a flop off the front of the board. My foilmount patch wasn’t that strong despite the CF layer on there from another repair. If the CF had gone another couple feet forward that would have helped. Next board is all CF and probably a couple layers over the foil mount

You need a high density foam insert with carbon running all the way around to really add solid strength.
I hit a sandbar are 38kph and ate sand, but the mast and board stayed intact.

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Yes that is plan!

Got 2 ready to go for the next boards!

https://www.aliexpress.com/item/10000294716408.html?spm=a2g0s.9042311.0.0.616e4c4dDkSnhK

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what will happen when you hit something in this setup? Mast plate just change position in these grooves or board became destroyed like on photos earlier?

Going to have a couple layers of carbon over it so that should help. The failure before probably wouldn’t have happened if I had the carbon extend all the way to the front and had more then one layer, mostly it peeled off where the carbon ended (because I was cooling the ESC though the box I didn’t want cover it). Carbon will also be on top of the foam inside my box so that should help as well.

Hopefully the mast plate won’t move in the tracks, It will need to be fixed where the wires come up. Might even epoxy in the tnuts when I figure the ideal location.

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Hi @brycej,
Interesting build log.
I’m thinking about using same motor as yours FlipSky 120kv with a 200A ESC.
Regarding battery, I saw you made a custom 12s12p pack with Samsung 30Q cells rated at 15A which makes 180A total current if I’m right?
I’m thinking of building my own pack too, just I’m not sure which option to take.
I’d like to use big 7Ah cells able to deliver 20A.
Do you know which configuration could be enough for this setup.
I have no idea which current are needed. Did you experience current limitation with your pack?

Right now, I don’t think I’m drawing much more then 100amps of battery current on startup, but having the bigger capacity is good for 45-60min of riding, also keeps everything cooler in the box. At 12s, I got 36Ah of batteries, I’d shoot for something along those lines. So probably between the two of those constraint a 6p setup would be good.

Which 7Ah cells were you looking at?

I’m thinking of those LiitoKala Lii-70A 32700 lifepo4 3.2v 7000mah.
They are rated 30A but I saw a test where they say they would hardly go after 20A due to heat.
I was thinking building a 14s5p pack which would make 44.8v/35Ah/100A.
The only thing bothering me is if it will be enough to sustain current draw or if I need to increase parallel. If you say 100amps is the average it might be sufficient though as that would be exactly what the pack can provide continuously. Otherwise I’ll go for 6p or more (just that they sell allready made 1s5p so simpler)

EDIT: another thing is weight… cells are around 150g each which would make a total 10.5 kg. which might be a bit heavy?

You probably are going off the beaten path for batteries in foils, looked like one or two other people on the forum have used the LiFe batteries, but yeah, they are definitely going to be heavier then the liion batteries!