Not sure what it is but i use the orange urethane belt off mcmaster. Leaving it to cool completely in the welding jig seems to be my tip for success. Never managed to do one by hand and have it last.
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Started on my 150g drum spinner robot. its tiny. the total size 57mm x 57mm x 19mm will be run off a 100mah 1s lipo.

Shown is a US penny for scale.

Frame will be cnc milled out of titanium.

Nice, that's extra tiny
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

I want to wire the rx and drive motors with 1s only and run the weapon esc off of 2s.
This is how I am thinking of wiring it.
will this work or am I crazy?

This is the esc I am using
http://www.hobbyking.com/hobbyking/store/__37944__Hobbyking_YEP_7A_1_2S_Brushless_Speed_Controller.html

your ESC doesnt have a BEC?

I'd be wary of dumping unregulated 1S voltage into your Rx, it might see sags and spikes that reset it during operation
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

no it doesn't it just has an regular rx connector no power leads whatsoever.

Some Rxs will run happily off 2S which is prolly safer than 1S for resetting
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Most low voltage ESCs will have a built-in BEC and the power is supplied down the signal cable. You can easily test that by just connecting the ESC to your 2S battery and connecting the signal lead to from the ESC to the receiver. If the ESC has a built-in BEC, the receiver will power up without a separate battery.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Oh one major modification I would make is run them off a common ground and don't let the 5v from esc go into RX.

Stev
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Steven Martin
Twisted Constructions
http://www.botbitz.com

I've tried running these rx's off of 2s before but they get super hot.
even though they are spec'd at 3.6~9.6V
I am worried at the 2s voltage I would burn them out.

Also if it regulates the voltage to 5v from the rx then the esc wont get the full voltage of the battery. it only has the receiver plug no external power plugs at all.

I just checked the esc and it does not have a built in BEC.





Is this what you ment about common ground marto? the 5v line does not go back into the esc only the signal line.

Alternately I could take the positive line to the rx from the top cell and run it through a 5v regulator but I don't have a lot of extra space inside my robot.

Yeh that is a what I meant. You can still probably keep the ground wire to RX if you want as they will be the same. But isn't necessary.
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Steven Martin
Twisted Constructions
http://www.botbitz.com

I suppose it is a tiny ESC so a BEC is probably going to make it twice the size or weight.

Having said I would still use an external BEC, unregulated Rx voltage is bad mkay. IMHO
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

You probably don't need a fully fledged ESC, just a voltage regulator will do at that scale (at least for the rx).

Something like this should be pretty easy to wire up, weigh nothing and means you can have just the one power input to your bot.

http://au.element14.com/diodes-inc/ap1117e50g-13/ic-ldo-reg-5v-sot223/dp/1825292

You can have issues with split power if you wind up having say the RX on and the ESC off as you are now pulling one of its input pins to 5 volts above its power pin.

If you want to run more stuff off the 5v rail or that sot package is a pain in the butt to solder to take a look at a 7805, more than once I've soldered some wires to one of those and called it done ;-> Also you will probably find a 7805 for sale in any "electronics" shop that has components.
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Mechanical engineers build weapons, civil engineers build targets

Okay third times the charm. How does this look?
Also batteries came in today they are much smaller than i thought and lighter too.

Yeh that is probably the best way to do it. Adds in a 7805 but safer than running off 1S as voltage sag could cause drop out and safer than trying to push 8.4V through the receivers poor little regulator.

Best of luck

Steve
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Steven Martin
Twisted Constructions
http://www.botbitz.com