Cutting ESC power under load

Safety system is a Aleph PS-3150 it is a magnetically activated reed switch. It talks to the Arduino which handles all the signal processing. The rider wears a ankle leash connected to a small neodymium magnet which has an eye-hook on it. The magnet will sit on top of the aluminum ESC enclosure.

This is not correct. The VESC has a very well defined behaviour.

Where can I define it? It certainly simplifies the circuit and makes it more robust grounding it with a relay. A google search for “vesc loose signal” and you will see numerous accounts of boards running off going full throttle on loosing signal.

How do you prevent the magnet hitting you? How do you start when laying with your breast on the board? Where is the leash when you stand on the board? How do you prevent triggering the safety leash unwanted?

Open the Vesc tool, goto ppm page, read there.
It can be caused by a faulty programmed remote as well.

Got it! I will checkout those settings. It’s a jet ski leash attached to the magnet. I have 19 days to complete my build so not everything will be addressed in version 1.

Please tell us where you got that from?

At least all my VESC have a really clear behavior for out of range signals: heart beat stop. Then the configured fail safe routine jumps in.
See here: https://github.com/vedderb/bldc/blob/80fffdea7340f3b7d4faea63f24339c2212ab62f/applications/app_ppm.c

and here:
https://github.com/vedderb/bldc/blob/master/commands.c#L372

Please, before making more statements on the forum, inform yourself.
As you stated very well at different places now: The VESC is completely open source so look it up!

My apologies working on bad information. Thanks for the update!

I’m going to go with…the same way it would work for anyone that’s used a surfboard or SUP leash deals with pretty much all of this except triggering the safety leash unwanted, but with a std SUP coil leash it would be out of the water while foiling and not long enough to get into the prop…

On my second build, I made a lanyard from a old ESD cord, a magnet. It works well. But it would smart if it hit you in the eye or tooth. Its not perfect.

It is connected to my life jacket near my waste. Laying on the board I feel for the lanyard at my waste, reach about where my fwd foot big toe would be and plug in. It stretches to about 5 1/2 feet.

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Thank you for sharing, this makes me feel a bit better about my initial solution. It sounds like all the issues of kiting with a board leash are present with this one too unfortunately. My mind goes toward putting the magnet in a foam pouch. Based on your experience, would this help?

You just need a hall sensor witch trips a 5v / 12v relay which then trips a 200a 12v relay which disconnects the power. Been using this for 3 years now no issues.

Which ESC are you using?

Again, when you using a big ESC like an Flier Boat 400A it will works great. But when you do it ihr a 200A VESC with 12S you have a very big chance to damage the VESC!
A lot of examples here in the Forum exist.

I wonder why that is? Is it because the larger ESC’s tend to have bigger capacitors able to withstand the back EMF spike?

I am not a specialist but it seams that big ESCs have enough reserve for Voltage spikes that are coming from the rotating motor.

Look around that forum, I remind it exists about this problem a own thread…

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I’m carefully following the discussion because I’ve installed a RED switch myself instead of the original power switch of my ESC Heifi SWORDFICH Pro+300, which is also equipped with the capacitor bank option (Suitable SWORDFISH series ESC to deal with the HIGH power and HEAVY load.
Capacitor: Rubycon 63V 470uF x 4=1880 uF).
Do you think I’m risking huge damage in case of a power cut at full Regine?
Thanks

What does your drive train look like? It’s possible to calculate this.

This is the Pacificmeister model : Motor SSS 56104 500kv’ / pack li-ion 12s12p (Sony VTC6 , 36 Ah , 1555wh )

I’m not exactly sure what destroys ESC’s in regard to back EMF (voltage/current or some combination of the two) I just know to not let it happen when it has no where to go. If you took off your prop and spun your motor shaft with a drill to max RPM it spins after killing power while riding in water, then used a multimeter to measure voltage/current at motor wires you could figure out what your ESC is experiencing.

I was going to suggest using electric motor power equations but with a mechanical gear reduction (I think that is a part of the Pacificmeister model?) I think it would be hard to calculate.