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[Mikecotton]

i am using a Hobbyking brushless 40A esc with leopard 2628 motor rated at 22A max.and 3S lipo. This esc does not come with a built in switch, unlike others I have used. My question is what switch do I need in the circuit? All of the switches I have found are rated much lower than that. How do the esc with built in switches get away with what looks like a lightweight switch ? I’ve put myself down for an Action P106 but they don’t know when they will be producing them again !
Mike

[canabus]

Hi Mike
I use the Hobbyking car ESC's with on/off switch and have no problems with them.
The 45 to 100 amp ones use the same program card and may be the 30 Amp ones do to.
Canabus

[kinmel]

If the switch goes in the 5v BEC power supply to the radio receiver, that uses very low amps.
A switch in the motor battery supply line that feeds the ESC needs to be able to cope with the higher amperage.
Either method works.

[Mikecotton]

Thanks Kinmel, simple when you think about it, which I obviously did not do enough ! I have read that the simplest switch is a plug and socket but was worried about powering the motor while it was not under control of the esc.
Canabus, the problem is that my esc does not have a switch, but thanks for replying
Mike

[imsinking]

The switch ? as stated it's in the BEC supply from the ESC , no switch no problem , just use a fuse holder & pull the fuse out when your finished , you do have a fuse ? it's a must with brushless motors their ampaholics & take everything they can out of the battery , if you get weed or feathers wrapped round your prop and no fuse OH BOY all sorts of nasties can take place , I use the fuse board from component shop & just pull out the blade fuse when I'm done . . .
Bill 

[Mikecotton]

I must engage brain before posting ! That is exactly what I did on a sports boat I knocked up. I left the esc switched on permanently, mounted a water-resistant fuse holder on the outside and used the blade fuse as a safety link.
Thanks Bill

[RST]

I guess if you wanted a quick on/off device short term to stop a prop spinning for an esc without a switch you could just buy a 100mm servo extension lead and cut the red wire and fit a switch there? Presumably that's doing the same thing? Personally I find it handy to have some form of quick switch somewhere? Won't cut overall power obviously.

[NickelBelter]

The switch ? as stated it's in the BEC supply from the ESC , no switch no problem , just use a fuse holder & pull the fuse out when your finished , you do have a fuse ? it's a must with brushless motors their ampaholics & take everything they can out of the battery , if you get weed or feathers wrapped round your prop and no fuse OH BOY all sorts of nasties can take place , I use the fuse board from component shop & just pull out the blade fuse when I'm done . . .
Bill

If this is true, why are cordless tool manufacturers switching to brushless motors for longer runtimes with the same size battery packs?   

For the OP, the motor is always under control of the ESC, so as long as you make sure your transmitter sticks are in neutral when you power the system on it won't 'take off' on you.  However, if you want a switch because its handy and convenient and easier to work with wet hands, then I'd recommend finding out what the actual draw of your power system is and looking at automotive switches as they have higher amp ratings.

[imsinking]

The tool people are changing to Brushless motors in their products for the increased torque you get , auto switches are only good to 12 amps at a pinch , you need to use heavy gauge wire for your circuits as bell wire will heat up VERY quickly , I'm new to Brushless it's a different world to DC motors , for boats you can overload the motor with too big a prop / weed / feathers jamming the drive train , the motors will just go GIMME GIMME for amps , and things start melting , I use 14 gauge wire and Deans connectors (good for 60 amps) got weed wrapped round the prop & the wire partially melted and the Deans blocks melted completely , the ESC was OK it was a 100 amp one , I use 25 amp fuse blades , strangely that didn't blow , I use 11.1 LIPO batteries 5000 mah their good for 100 amps in bursts    not bothered at all after the event . . .
Bill

[john44]

Hi guys, you can't be too safe as regards fusing, a old member of our club, sadly he passed away
A couple of years ago. He fitted a brushless setup to his percassa boat after sailing he switched off his
Bec feed to his Rx and forgot to disconnect his battery to the esc (blue Chinese type)
Put his boat on the back seat of his car and went home.
Later to be alerted by neighbors telling him his car seat was on fire.
The still powered up esc had overheated and cought Fire burning the boat and ruining his car back seat.
A costly lesson about always disconnecting the MAIN batteries after sailing.


John

[Mikecotton]

If the amperages involved are so big, why are there no switches capable of handling them in the model market ?
Just a thought  - and thanks for all the interest/suggestions
Mike

[JimG]

Probably because a switch that can safely handle such high currents would be too large. Switching on and switching off can cause a large spark at the contacts which can weld them closed if they are too small. I used to use a microswitch to switch a 540 in a fast electric that would flatten a 3000mAh NiCd in less than 5 minutes. After a year or so racing when examined the contacts were pitted and some others found the internal connections melting. At one point we used a sequential set of two or three switches where initial current went through a high wattage resistor to reduce the initial surge to protect the final switch.
Jim

[malcolmfrary]

If the amperages involved are so big, why are there no switches capable of handling them in the model market ?
Just a thought  - and thanks for all the interest/suggestions
Mike

There are, they just happen to be too big for use in models.  Big current, big switch.  But switches in models don't usually operate to flat-out running conditions. 
It has to be remembered that any switch has two current ratings, what it can carry, and what it can switch.
In the in-between stage of between fully connected and fully open, it can't carry anything like as much current as when it has got to fully settled.
The small switches on ESCs just decide whether the control circuit is switched on or not.  Transistors are a lot better than they used to be, but there is always a chance of there still being a very small leakage, so actually disconnecting the battery is the best option.  Whether this is by removing a fuse link, a switch, or unplugging it is a matter of choice.

[malcolmfrary]

Probably because a switch that can safely handle such high currents would be too large. Switching on and switching off can cause a large spark at the contacts which can weld them closed if they are too small. I used to use a microswitch to switch a 540 in a fast electric that would flatten a 3000mAh NiCd in less than 5 minutes. After a year or so racing when examined the contacts were pitted and some others found the internal connections melting. At one point we used a sequential set of two or three switches where initial current went through a high wattage resistor to reduce the initial surge to protect the final switch.
Jim

When apprenticing, I was told that the "micro" in microswitch did not refer to the size - they were always quite large for their current handling ability.  It referred to their operate time between one state and the other being in microseconds. 
And in later years I had the chance to observe one operating on a scope - it was not a clean step of a trace, it looked like a round of applause, and was why the counter circuit that it was operating counted to a lot every time instead of just ading an extra 1.