2013 Build Rules and Competition Regulations

[swanaldo]

Re: 2013 Build Rules and Competition Regulations

Hi Craig....I have a friend who is very good with the old circuitboards...I have asked him to look into making a voltage cutoff switch for my robots and Yank. He said it would be possible and is looking into it tonight. I will get a few made up if there is the interest???

[craig_colliass]

Re: 2013 Build Rules and Competition Regulations

Hi Shane

I would be interested in one. For the new saint

Perhaps if this is a point of interest for a lot of people it may be worth starting a new thread to discuss the parameters and functionality of such a device.

[Bodge Job]

Re: 2013 Build Rules and Competition Regulations

a device would be useful, as far as im aware sabertooths are the only escs with low vloltage cut outs, although a telematary system could also be used, http://www.hobbyking.com/hobbyking/stor ... metry.html
would give you a warning when your running out of power, and need to go easy? although i sopose that relies on the roboteers to stop, which could be hard in the heat of battle.

[adz600]

Re: 2013 Build Rules and Competition Regulations

but such a device could be linked to an external bec control relay, so when switched ie, siren or light the output signal could engage/disengage a bec relay causing control to be lost and therefore all controllers and weapons etc would revert to failsfe positions,

just an idea i have considered

[widow_twanky]

Re: 2013 Build Rules and Competition Regulations

One thing I think is an issue as much as where people buy their lipo's is were people buy thier lipo sacks. A good lipo can cause the same damage if it catches fire as a cheap one. The major failsafe is that they are contained in a device which should prevent serious damage occurring to anything else.

There are a few 'fake' lipo sacks which you can buy and these simply do not do their job.

http://www.youtube.com/watch?v=ZEkewCjiDs0

Personally I always buy from a good UK supplier (al's hobbies, Hurricane models etc). Which gives some security. That said it is not unknown for reputable dealers to get duped by their suppliers (horse meat lasagne anyone?). Would it be sensible to introduce a 'metal box' for charging as this can't possible be faked?

Andy

[razerdave]

Re: 2013 Build Rules and Competition Regulations

Has anyone had any luck with a low voltage cut out for Lipo's ? If the ruling does get changed to mandatory then my robot would fail on this point.

Also, I've been reading the pages, and I totally agree with Ed regarding a lipo charging table and the fire extinguishers. My only problem with charging lipo's and having to stay with them, you miss all the action, especially if you're at the Robochallenge event (can't see the arena from the pits).

I did read that lipo's have to be secured down now. My Lipo's have padded protection around where they are situated so they don't rub on anything, but with the lid off I can move them freely (the bar that holds them down goes in with the lid). will that suit purpose or do I need another securing method ?

I don't want to be disqualified before I get to the UK champs.

[psychostorm]

Re: 2013 Build Rules and Competition Regulations

OK, help my aching brain. At which voltage should the Lipos cut off at?

[Ellis]

Re: 2013 Build Rules and Competition Regulations

Is there potential in modifying one of these things? http://www.ebay.co.uk/itm/Low-Voltage-L ... 337f8a9f33

We have already purchased one to experiment.

[terry]

Re: 2013 Build Rules and Competition Regulations

Lipos don't like going under 3volts per cell.

[typhoon_driver]

Re: 2013 Build Rules and Competition Regulations

If we are being realistic about a cut off then it will have to cut power to the receiver or robot as an alarm will be drowned out in the arena and a light would be easy to ignore or confuse with the power LED. That raises two issues, if it's a main power cut off it would have to be capable of flowing 200A through it. Unlikely to be reliable or cost effective.

That leaves you with cutting power to the receiver which again is not ideal as you still have a robot capable of movement by itself (although of course the tech check should omit this risk).

Other issue, how do you test the cut off during the tech check?

[Ellis]

Re: 2013 Build Rules and Competition Regulations

Set our cut offs to a standard of 3.35v per cell and have a discharged battery to hand (in a LiPo bag) that will be slightly below that?

I'm not entirely joking.

I don't know how easy it is on these things to change the point at which it sets off the alarm, if it can be done on the fly we could set it well above the safety mark for tech checking and lower it to a realistic point before battle?

[Eventorizon]

Re: 2013 Build Rules and Competition Regulations

I bought a cut off from technobots and it has a small rotary resistor with which you set the cut off point. It goes from 3.5 to 3V and even has a few little lights on it. I went without it last year but I may slip it in this time if there is space.

And David, we hole our Lipos down with industrial velcro. Its a pain to get them out but when they are in they are going nowhere! I had to Lever them off with a wooden ruler first time round. I was afraid I had got them stuck!

[team_mute]

Re: 2013 Build Rules and Competition Regulations

Is any good, never used lipo's but just looking at whats needed

http://www.dimensionengineering.com/products/liposhield

[Max]

Re: 2013 Build Rules and Competition Regulations

LipoShield is intended for aircraft with 0-100% style one direction only throttle. A future product will be aimed at cars.

It will not work with robots as it does not reset to 50% throttle which is what turns of our escs, it resets to 0% which is full speed reverse!

[team_mute]

Re: 2013 Build Rules and Competition Regulations

We were thinking of putting it on the wotty, on the on/off channel so it will just shut the speedo down