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Battery safety switch


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What can I use by way of a switch or whatever between LiPo and ESC so as to easily and positively disconnect the power to the motor? Max draw 20A and weight isn't an issue.

Question arises from a combination of arthritic fingers, tight XT60 connectors and an earnest wish to avoid digit damage ...

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Why is it rare to come across ( or maybe I don't look in the right place) a Brushless ESC that has a built in fly lead with arming switch .like a mini - flight switch.

This obviously allows the switching on/off of the model , in effect .

It used to be commonplace in the Pre - Brushless . Sub -C Cell Days. and were often referred to as " arming " switches.

Is it a cost cutting exercise by the manufacturers to now omit this switch ? or are there other reasons .

Is it preferable to physically bridge - out the power leads ?

Genuine questions , as I have limited knowledge on Leccy' Models and never really feel comfortable with a model that is armed and ready to go for any period of time .

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Even when those disable switches were fitted to brushed motor esc I neither used nor trusted them. In fact they were either shorted out or buried within the model permanently switched on. I just regard a model with the flight battery connected as permanently 'ON'.

I don't use an arming connector but rely on using a throttle disable switch on my Taranis transmitter with a verbal warning if it is in the 'ON' state. As the distance from where I connect the battery to where I start to taxi out to take off is about 3 steps I really don't see the point of the extra complication in my case. If there was either a greater distance from the pits or a long wait then I just delay connecting the battery. Even with my DB Tiger Moth I can't see how an arming plug would make it any quicker or safer as all I have to do is open the hatch and connect the battery positive 4mm plug.

Geoff

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Presumably you could have a dual pole switch connecting / disconnecting two of the wires to the motor. The only issue would be a lack of "beeps" to show that the motor is switched on the beeps (I believe) coming from the motor windings. I suppose putting a SPST switch in a single motor wire would suffice (the motor would likely just cog back and forwards).

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Makes Sense Geoff , but the part that I don't like is faffing with connecters in close proximity ( hands and eyes ) to the prop .

Especially if I am having 2 flights on the same lipo .

I have one Brushless Esc with an arming switch as yet unused , and never had an issue with the same on brushed setups ( jeti) . but never say never ?

The ability to " switch off " the model at any moment in time by the simple flick / slide of a mechanical switch was / is somewhat comforting , and extremely convenient .

On a Hacker ESC I posses , it has an arming switch on a fly lead to enable / disable the BEC function according to preference .

It is totally identical to the arming switch on the previously mentioned brushed esc ( not hacker) I have which arms / disarms the motor.

I am assuming that Hacker at least have some faith in this switch ?

Others may disagree .

It just seems like a large hammer to crack a small nut to physically bridge out the power cables . not mention added weight , faffing , more connections to go wrong etc .

Will now try to create a motor disable switch in my FF9 Tx if possible , but advice probably needed , again.

thanks for your comments. advice always welcomed.

P

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While a physically removable link or ESC arming switch is undoubtedly a safety boon, my preference is to ensure that any flight battery can be connected without jeopardising any part of my anatomy!

The logic here is that ANY safety link/switch solution is prone to human or other error - forgetting to remove the link, accidental shorting of same, switch failure - or wrong model selected etc. etc.

If you develop awareness of the hazards and build out the need to reach through prop arcs or be in front of a model when connecting the battery then I think you're less likely to get a nasty surprise than with any number of safety devices - but I'd still advocate their use where possible. All my electric models have locking throttle disabling switches which must be in the safe position before the transmitter will arm BUT I DO NOT RELY ON THEM!

...and handle and carry the model out in exactly the same way as you would with an idling IC engine.

Edited By Martin Harris on 20/07/2016 20:36:45

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Posted by Peter Android on 20/07/2016 19:27:02:

Genuine questions , as I have limited knowledge on Leccy' Models and never really feel comfortable with a model that is armed and ready to go for any period of time .

it would not be a good idea to leave a model in that state. I connect the battery just before a flight on a restrained model. ie like starting up a glow motor you consider the electric model as running even though the prop is not turning

Edited By Phil 9 on 20/07/2016 22:43:36

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Posted by Spikey on 20/07/2016 18:45:50:

Question arises from a combination of arthritic fingers, tight XT60 connectors and an earnest wish to avoid digit damage ...

I find these a boon. Also worth buying some spare adapters in the same order - but at the moment the tool with adapters are listed at less than half price !

I'm another Taranis user. The set up I have on that is simple to use but comprehensive throttle disable/enable with audible warnings & in the case of E-gliders reminders whilst gliding if power has been left enabled.

I also have MPX Cockpit SX converted to dual 35meg/2.4gig mainly used for my vintage models that are fitted with older type Frsky Rxs. On this Tx I've used free mix options for a throttle disable function operated on one of the sliders. Unfortunately no audible warning possible with this Tx.

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As OneTennor suggests, a jack plug would be fine if it can handle the current but they are generally made for low current applications .

Throttle disabling from the TX is not a solution to the problem . Interference or component malfunction could allow the current to flow at any time . As already suggested, if the battery is connected then treat model as if the prop is spinning.

Edited By Engine Doctor on 21/07/2016 09:01:41

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Emcotec sell sold state switches designed to arm models without a mechanical plug or arming plug.

Otherwise, you can program most decent txs to use throttle cut as a way to arm the esc.

My futaba 8fg uses 2 switches to arm the motor. For larger models, I use a arming plug made from a connector.

Simple swtiches wont handle the current well and may be quite large and heavy.

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As others have mentioned, nothing other than physically (not electronically) cutting the main power feed to the ESC will guarantee that the motor is disarmed. So long as the power is there, there's the potential for the motor to start unexpectedly due to interference, faulty ESC, faulty receiver, incorrectly set fail-safe, to name but a few.

One only needs to cut the positive supply lead, and a jumper plug located out of the way of the prop is the easiest way to do it.

Of course, proper procedure (transmitter on first and off last) goes a long way to reducing (not eliminating) accidents, as does a throttle-cut switch programmed in the transmitter, and arming switches on ESCs can help, so long as you remember to disconnect the battery straight away.

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I echo Allan's thoughts. My USA flying friends told me a long time ago to treat a model with a battery the same as you would treat a loaded gun - if the battery is in the model and connected, then the model isn't 100% safe. Thankfully, we don't have the same gun freedom in this country, but the philosophy still applies. All my larger models, where battery access is difficult, use one of Emcotec's Safety Power Switches.

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It is the same for UK Service folk, Gordon.

People rely upon tech only in a lot of cases, indeed on many threads here people rely upon their Tx to ensure the motor is safe. That is a disaster waiting to happen!  

The only safe way to ensure the prop does not rotate would be to isolate the motor. There is nothing wrong with looking backwards and using something physical and as simple as an xt60 arming plug.

6970 c.jpg

(please excuse the Deans plug example but I am not at home to take a piccy of my XT60 wiring)

Edited By John F on 22/07/2016 13:02:54

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