What do you think about these electrics safety solutions?

  1. I am going to use an inline fuse between the ESC and the Batteries. Probably 150A or so. That will stop the ESC from drawing more current than it can handle.

  2. Hopefully the ESC will have the feature to shut off if it looses connection to the remote. How exactly does this work?(Don´t have the motor and esc yet. Waiting for direct drive from alien).

  3. I would like a switch on deck that can cut off the batteries completely. There are a lot of car battery switches, rated for 48v and 200A, but none of them are waterproof. I would like to be able to cut the power from the outside. That will also be more comfortable. You can prepare the batteries and the board, then get ready to get into the water and just turn the switch.

  4. It would be good if the batteries get disconnected when a safety leash is pulled. Do you have a solution for that? Maybe this could be done in combination with step 3.

  5. I will add temperature sensors to an Arduino that monitor motor, ESC and battery temperature. Ill probably add a little display with the readouts and have an alarm sound if they get too hot.


I use a plug linked to a safety halyard. Climb on the board and plug it in. If you fall, the plug is pulled before the rider hits the water.

I hooked the plug in to the negative wire between the battery and the esc. The wires come up to the top surface of the board and terminate in a female connector. When the male connector is plugged in, the circuit is completed.

yeah sure, you pull the leash, it is disconnected and then water shorts it again…

well, you can just build an antispark switch, google it. It should be something like a 10V switch triggering a high amp mosfet.
For the Triggerswitch you can use anything, e.g waterproof pushbutton, or maybe some magnet switch at a safety line.

Good point…I’m using this on a fresh water lake only.

fresh water is also conductive?!

Tap or lake water is not very conductive. Here is a snip from Wiki:

In many cases, conductivity is linked directly to the total dissolved solids (T.D.S.). High quality deionized water has a conductivity of about 5.5 μS/m, typical drinking water in the range of 5–50 mS/m, while sea water about 5 S/m[2] (i.e., sea water’s conductivity is one million times higher than that of deionized water).

So fresh water is about 100 to 1000 times less conductive than sea water.

Here is a safety lanyard/switch that should work equally well in salt and fresh water … not too expensive either, $12.75.


Probably need to use this with a solenoid.

hello pacific master

I saw that you also used a kill off switch in your last video.
can you tell us the used article or the source of supply?
Also a sketch like this should be connected would be fantastic, unfortunately I know myself too little with the electric.
kudos for their work, this is top league and will inspire many more people :clap:t2:


4. You can use a reed switch
works the way shown in this picture. You can connect it in series with the signal wire to the ESC., or to some sort of Relay to cut the main power, if you cut the main power you must take some precisions.
also cutting the signal to the ESC is not ideal, but it works:p have used this configuration a few times. Currently we have the Reed switch connected to an Arduino which sends a signal to the ESC to “slowly” deaccelerate.

also we use a DEADMANS SWITCH on the controller you have to hold in to use the throttle

1 Like

Yes, I am doing a similar thing, cutting the power to the receiver (which will stop any signal to the ESC). I am using one of these hall effect switch sensors instead of a reed switch: https://www.amazon.com/dp/B00SWK15ZE/ref=cm_sw_r_cp_apip_qEwbMsOno52jN. Pulls the middle pin to ground when a magnet is close. Was a quick mod, I just taped the sensor to the inside lid of my ESC box and printed a guide rim to hold the magnet in place. And i printed a simple magnet enclosure where I added a print stop at the right layer, dropped the magnet in and continued printing to fully waterproof enclose it. Here is the Fusion model of my magnet enclosure and the rim: http://a360.co/2Adilnu. I am using this magnet: http://a.co/1xI80vz

What is your opinion about this one:http://alienpowersystem.com/shop/rc-ev-accessories/electronics/alien-antispark-power-switch-3-16s-300amp-max/
together with the magnetic switch

It is a bit expensive, I guess the parts are max. 20$

Thanks for the quick replies
I will take over the system 'interruption to the receiver’
is easier for me to implement :wink:

I was hoping this could take care of two problems.
Killing the esc with spikes from sparks (with time).
Saving the esc from cutting it off at full power,
I do not know that would destroy it or not.
Is there a way to acieve this in a cheaper way?

I suppose the Pacificmeister way would do that cheaply. The Alien switch would in addition completely disconnect and reconnect the the batttery from the esc if desired for any reason. Is this correct thinking?
I do not know how quick the current shuts off or if it helps if the esc should be programmed with brake.

The only issue with doing it this way is how the ESC reacts when losing Rx input. Some wait 0.5seconds before killing power, some over 2seconds. YMMV.

Hi Guys, Just came across SSR (solid state relay) switches and will try few of those to disconnect the power from the system by a switch:



Will appreciate your comments about it. It is rated 220vDC, 200A load voltage/current

Would like to learn more on what they do?
Remove voltage spikes?
Do they act like a breaker switch?

SSR is a solid state relay - its basically MOSFETS used to turn on and off the current available to the load side. Similar to a contactor, but solid state device (silicon).

ok, but still not sure the benefit of it or how to use it?