Are LiPo batteries safe for HW robots?

[craig_colliass]

Are LiPo batteries safe for HW robots?


I know it is a strange question as it depends on lots of different things. Not least on your own view on what€™s safe!
But I am concerned that with the saint or some other hitting weapon robot a LiPo battery may be ruptured and catch fire rupturing other cell in close proximity.
Do the EO€™s have plans and equipment to control dangerous situations like Lipo fires?
Are there any design considerations like steel battery containers to house these battery types in the robots.

Just wondering about this

Thanks
Craig

[blazerbotics]

Re: Are LiPo batteries safe for HW robots?

Lipos arent allowed in heavys. The only lithiums allowed in heavys are the A123's.

[geeza]

Re: Are LiPo batteries safe for HW robots?

The FRA rules on batteries are currently being rewritten to allow new advances in technology. But this will not include LiPo batteries in the heavyweight category. But since they are allowed in FW and Ant categories, roboteers should bring the necesary equipment to deal with any accidents to each event.

Further to Alan's post the A123 technology is based on LiFePo (or LFP for short) chemistry not a Lithium polymer chemistry which is nowhere near as stable. As the FRA rules stand A123's are only allowed in feathers or below with the exception of the long running trials in Thz and KO, but this will be changing soon.

There is a need to re-write the build guidelines to cover the use of A123 cells in heavyweight
robots after the extended trials. Ed Wallace offered to re-write the relevant section for review and
agreement at the next meeting. - from last FRA meeting minutes.

[craig_colliass]

Re: Are LiPo batteries safe for HW robots?

Thanks for clearing that up Alan so LiPo batteries will never be allowed for HW. thats got to be good.
Do Lithium 123 batteries have any problems with safety if they get wacked? I know Nicad get very hot and smoke if shorted out, do 123 batteries do the same?

[Kenny]

Re: Are LiPo batteries safe for HW robots?

i don't see why they arn't allowed, there allowed to run in feather and ants and they running spinners what can cut them up, also the reason why the lipo's go up is not charging them right and mishandling, lead acid batteries go up alot worse, a few of us have had lipos falling out the sky 100ft with no damage, a 10s lipo which is 37v with a 5000mah could run a heavy and they are the same being used in feather's

[typhoon_driver]

Re: Are LiPo batteries safe for HW robots?

Well I think I'm the expert on buggering over A123 cells. I can quite safely say that all that happens when they go is they get hot but thats it.

I have had a cell get so hot it split open but absolutely nothing else happened.

[leorcc]

Re: Are LiPo batteries safe for HW robots?

Hornets disc went through a A123 cell of Plofbox2 and nothing happened there either.

[grant_ploughbot]

Re: Are LiPo batteries safe for HW robots?

I have been using lipos in feathers for over 3 years now. A similar rated pack to what turbulence used to run in Nicads.
equivilent of 24v @ 5000mA and never had a problem. They are perfectly safe as long as your not stupid with them.
As regards to charging them, do it properly and you will never have a problem. Its not actually very likely a lipo will catch fire either. They need to be almost fully charged and punctured to have a good chance of catching fire (i know, i've tried it myself ).

If they go up in the arena, well who cares? The fumes are less toxic than nicad fires, and the robot needs to have a metal base to run lipos anyway. So it cant harm anyone.

They need to be charged in a metal box of some form aswell (personally prefer in the robot myself)
so it shouldnt matter if they go up when out of the arena either due to bad charging.

[craig_colliass]

Re: Are LiPo batteries safe for HW robots?

When I read
Hornets disc went through a A123 cell of Plofbox2 and nothing happened there either.
And
I have had a cell get so hot it split open but absolutely nothing else happened.
My fears are certainly helped.
I don't want to cause any fires from hittingThz or KO. I had visions of me burning down the arena

[Kenny]

Re: Are LiPo batteries safe for HW robots?

the fires arn't has bad as people think, its not like it sets on fire, it has a type of thrust fire when pressure is released for a few seconds and moves onto next cell and repeats till all the cells have gone

[big_nipper]

Re: Are LiPo batteries safe for HW robots?

Little Spinner ran a 37V 3.3Ah LiPo at its last event. That in its self is big enough to run some heavyweights also. It does seem a little daft that a feather weight has no limit on the size of LiPo pack but a heavy cannot run any. Maybe a pack capacity limit is needed or sooner or later someone will have a featherweight with a 20Ah 10 cell pack in it.

[grant_ploughbot]

Re: Are LiPo batteries safe for HW robots?

are we limiting it to 9cell lipos then lol.

[craig_colliass]

Re: Are LiPo batteries safe for HW robots?

I think Mark has a very valid point.
What size of LiPo batteries are considered safe by the FRA or the EO€™s.
If the size of the LiPo battery, could run a HW, but is in a featherweight why is this considered safe, but the same LiPo pack in a heavy is banned!
I€™m sure their people out there with opinions on this point.

[grant_ploughbot]

Re: Are LiPo batteries safe for HW robots?

I think as the popluarity of lipos in featherweights increases as it is doing then time will tell what the FRA/EO's feel safe to run.
So far, there are lots of robots running them, and have been for years without a single problem or fire. One point that should be considered with using lipos for an event organiser is whether the user is knowledgable of the correct usage and competant enough to follow it through. Its part of the tech check to make sure all safety precautions are in place, and as long as those guildlines are followed then i cant see any reasonable size lipo being much of a problem. I have seen a fair few nicad fires, not a single lipo fire at an event yet!
I do think a few rule changes needed to be made, as at the time no one had any proper knowledge of lipos in use, and i believe most people are a little scraed by the horror stories and videos floating around.

[geeza]

Re: Are LiPo batteries safe for HW robots?

Grant there are those people like yourself who know what they are doing and will look after their packs, but then we know that there are those who won't. If LiPos were opened up to the higher weights there will be people who have huge current demands so need bigger capacity than one pack from a feather even though there are packs with very impressive specs. I think it is several packs all going up at the same time that people are worried about. Especially say after an event on the way home, the robot is chucked in the car, not balenced charged or otherwise. In a feather you pull over and pull the feather out quickly, not possible with a heavy. Maybe you have a separate transport box, but the one time you forget to take them out of the robot, bad things happen.

But keep the comments coming they will be disscussed at the next meeting.