2013 Build Rules and Competition Regulations

Following discussions last year and development of the LiPo trials in heavyweights during 2012 I am pleased to attach the Build Rules and Competition Regulations for 2013.

Main changes to the Build Rules:
* 2.2 Wording changed to Degrees of freedom
* 6.6 Voltages changed to maximum values of 75V for direct current or 50V for alternating current
* 7.1 Additional requirements for protection of batteries
* 7.4 LiPo approved for use in heavyweights
* 7.5 Cell count for Lithium increased to 12
* 7.8.1 LiPos MUST be balance charged
* 7.8.8 Added requirements for protection (Replaced with 7.1)

Main changes to the Competition Regulations:
* Updated Immobilisation Rules
* Updated Pinning Rules

There will be a period of consultation until the 23rd February 2013.

Please discuss here or email info@fightingrobots.co.uk

I'm glad to see that lipo's can now be used in heavyweights. However (and perhaps I'm missing something here), how can we use up to 75V DC current if the max number of cells is 12 for lipo and limited on other battery types to give well below this?

Not saying that I want to operate at anywhere near that voltage but I'm just being curious.

2 8S in Series?

Or does that bend the rules too much.

I think 75 Volt is a bit much. Why did it go there?
In section 7.5 it says LiPo cells are 3.3 V. Shouldn't that be 3.7 or 3.6, making the max. quantity of LiPo cells 10.

Quote:

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Originally Posted by typhoon_driver

I'm glad to see that lipo's can now be used in heavyweights. However (and perhaps I'm missing something here), how can we use up to 75V DC current if the max number of cells is 12 for lipo and limited on other battery types to give well below this?

Not saying that I want to operate at anywhere near that voltage but I'm just being curious.

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In explanation:
75V DC is the limit before equipment falls under the Low Voltage Directive.
The rule is now a maximum limit as opposed to a vague mean value.
During charging batteries peak at much higher voltages (30 cell NiCd could hit 60v).
Voltages are limited by the batteries used.

Quote:

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Originally Posted by Marien

I think 75 Volt is a bit much. Why did it go there?
In section 7.5 it says LiPo cells are 3.3 V. Shouldn't that be 3.7 or 3.6, making the max. quantity of LiPo cells 10.

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LiPo cells during discharge are around 3.3v (depending on cell chemistry).
It's the peak voltage that is important. LiPo's are charged using constant voltage (4.2v per cell) so a 12S pack would be at 50v. As above, a 30 cell NiCd could peek at 60v.
This plus the availability of 6S packs vs 5S packs will give greater availability of commerically manufactured parts for the roboteer.

Low voltage cut out should be mandatory not advisory - what's the issue with requiring that, with robots much could be going in causing more discharge than advised. This is one of the biggest risks with LiPo's and yet nothing seems to be in the rules to mitigate the risk ?

Quote:

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Originally Posted by teamstorm

Low voltage cut out should be mandatory not advisory - what's the issue with requiring that, with robots much could be going in causing more discharge than advised. This is one of the biggest risks with LiPo's and yet nothing seems to be in the rules to mitigate the risk ?

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From Grant Cooper
Annoyingly it's almost impossible to buy a lipo cut off that sets off at 50% as they're all designed for planes etc that reset to 0%. The only ones suitable as a cut-off are the ones built into ESC's. As this isn't a safety issue at all and purely helps the cycle life of the battery I think it would be worth putting that as a recommendation rather than a regulation.

I said we should have it as manditory, to stop people pushing the boundaries of the batteries, but was advised that there are no commercially available units you can buy to do this.

John
www.RoamingRobots.co.uk

Regarding the new lipo protection bit, my fw has a monocoque chassis where the removable lid acts to hold the battery in its place in the frame. Is this now illegal?!