Main Power Switch for Heavy Octo


Well, I'm just at the end of my APM 2.0 based Octo build

(this has taken ages, and is based on a unique aluminum # frame variant - pics soon!).

The current take-off-weight is around 3.2KG

Power Chain specs:

4s/14.8v  5000ma nano tech LiPo,

8X  Turnigy Plush 30A ESC

8X  T-Motor MT2814 / 770KV

8X   APC  13X6.5 E Thin Electric props (these are perhaps a bit long for 4s...)

My rough assumption is that each motor would draw up to 30 Amps X 14.8V = 444 Watts.

Multiplied by 8, that should be a draw of 240 Amps, or something like 3,552 Watts...

That's about twice my wife's blow drier power!!!

(Perhaps next build should be a blow drier based quad?!)


For the very short period I have been setting up, I am getting tired of pulling

out the LiPo connectors, and want to insert a Single Throw switch on the main (+) line.

I got hold of a hot water tank power switch rated at 16A / 230VAC, which I guess should well

handle a draw of  3,680 Watts (see attached image).

Also, the switch is DPST, so I can actually send the current through both poles in parallel.

The switch is marked as SW2 in my previous discussion:

Any Opinions?

Thanks -



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  • Moderator

    No This will not work.

    The electrical rating of the switch is 16Amps AC. This switch will fail above 5amps DC.. the smoke will tell you which part has failed. !!! dont even try this. the ONLY switch I know of that could carry this load (in DC ) is the size of a plastic coffee cup and costs about 200$ made by tyco for golf carts.

    Find an electronic switch that can do this but remember that if its electronic then its not failsafe, one day it will bite you.

    The reason for the big difference in AC and DC ratings is the fact the the AC swithces off and provides NO power over 120 times a second. this breaks the elecrical arc when the switch opens and reduces the spark. DC does not turn off and so has a high power to switch off.

    I design high power DC systems on electric vehicles for a living. take this as correct.


  • Developer

    Emmpunkt is right. The high current spark will will most likely weld the switch shut after a couple of usages.

    The simplest solution is to make a "switch" using X60 or bullet connectors.

  • Do i understand this right? You want to switch 240 A with a 16 A Switch?

    You cant do this, the Switch will melt away.

    In Germany we wouldt say: It works....once.....for a short time!


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