A123 bankrupt - time to look at LiPo's for Heavies

With A123 systems filing for bankruptcy protection and the buyer who it had been hoped could rescue them (a Chinese manufacturer) not coming forward, and thus uncertainty as to what might happen to them and their technology, and certainly a drying up of cell availability ...

http://finance.yahoo.com/news/battery-m ... 43498.html

Now would seem a great moment for the FRA to add some real value to the community by saying how trials of LiPo's have gone, and producing the guidelines for teams to ensure they are used safely in robots. It is no longer something that can be ignored if the supply of A123's is at risk, unless we all think going back to NiMh and SLA's is the way forward.

Come on guys - now it looks like they could be needed and its a real opportunity to act and help people use a new technology safely, a core FRA role :)

As far as I know, no trials with LiPo for heavies were conducted.

On the other hand, Bullfrog is using LiFePo4 batteries from another brand. And that's the stipulation in the rules.

LiFePo4, A123 cells ain't specified.

Big nipper has had Lipo in for the last year.

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Originally Posted by terry

Big nipper has had Lipo in for the last year.

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That demonstrates the as far as I know.

Why the dependance on one brand of Lithium Iron Phosphate?

In my experience none of the other A123 brand makes have appeared to have anywhere near the performance of the A123 manufactured cells. I suspect Bullfrog doesn't show up that issue as it won't push the cells hard.

Big Nipper has been allowed to run LiPo's for a reason, to learn - would be good to share the learning and start to formulate rules to ensure the safe use of them.

With regard to the LiPo battery question I think the sticking point was with the Event Organizers who did not want to increase risk of fire with large LiPo packs in the robots or on the bench at their events.

The LiFePo4 type batteries used in Bullfrog seems like it may be a way forward and should not be overlooked, I am not qualified to risk assess these different types of battery, but if they are less Dangerous than LiPo's It makes sense to try them, as being reliant on a particular company dose seem a little short on options for the future.

When I spoke with Graeme when he popped over to my university he said that everything was going fine but that they had needed to make a pair of unibody 5mm Alu cases for the Lipos.
I am not sure what this means for weight but it may be that the safety features required for lipo's may make them almost as heavy as NiCads or SLA's.
The only advantages I can see would be a size reduction and an increase in maximum discharge.
Just a thought...

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Originally Posted by craig_colliass

being reliant on a particular company dose seem a little short on options for the future.

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The reality is though that's kinda what robots have been doing since it all started in one form or another if you want to be at the top of your game.

For SLA's you either ran a Hawker Genesis 13Ah or 16Ah or settled for something so inferior in current delivery it gave a massive disadvantage. Then for NiCads by far the best option was the Sanyo N3000CR cell (the yellow C-size cell that we all know and love). And for LiFePO4 it has be A123 who have produced by far the most powerful usable cell for robots.

So it's nothing new that the best option is always a 'single' option for any given chemistry, what's unique is that we've never been in a position before where we've not been able to adopt the 'next' battery technology, so we suddenly find ourselves at a development stall.

Just because a battery has the same 'Chemistry' as another brand, that doesn't make it the same battery - for example here is a LiFePO4 battery, 12v 6Ah, in theory we could use these to replace the packs we have in Storm II

http://www.batteryspace.com/Powerizer-L ... e-SLA.aspx

.... except then you realise the max discharge is only 12 amp MAX !! (and yes I realise there are other LeFePO4 packs out there before the pedants start, I'm just making a point that same chemistry does not the same battery make !).

So yes, what we do is aligned to A123's as the most sutiable implementation of a battery chemistry. If they risk not being available any more, I think that unless we want to (for the first time in our history) take a step back in development, we need to continue to evolve and maybe this should be used as a catalyst for that to happen. Storm II pushes the A123's to their limits and with NiCads now illegal our only option if the A123's needed replacing at the moment would be LiPo's !

One of the FRA's job is to ensure the safe adoption of new technology, it has been running 'tests' for over a year with Big Nipper, and one would expect the purpose of agreeing to run a test, was to have outcomes from the test, and then take actions based on those outputs - or it serves no purpose !

Is it completely silly to suggest that a LiPo charging bag be used inside the robot when running? In the event of a fire, would that not contain it and the fumes enough to safely get the machine outside? They're designed to do exactly that..

marvelous, now can we stop dragging our heels and get lipos into heavies right away?

As I've said all along, the featherweights experience far more in the way of knocks and G forces than any of the heavies do and they have been successfully run for years now.

Thank's ED

It's good to know that all manufactures and their products even if they are all the same technology are not all the same :idea:

Perhaps A123 are going bust because they don't hack it in the real world.

I personaly think the LiPo battery would be ok in heavies. but I don't run the shows.

The point about the EO's not allowing the technology in their shows when this was last discussed was not addressed. :shock:

Could it be you are looking to accelerate this technology because Storm 2 is old, out classed, slow and needs a boost?

Lights touch paper and stands well back. :uhoh: :uhoh:

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Originally Posted by craig_colliass

Could it be you are looking to accelerate this technology because Storm 2 is old, out classed, slow and needs a boost?

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I'm not sure that changing Storm II to LiPo's would improve things right now, the A123's are delivering what we need, and after much tweaking we seem to have a well balanced system again between motors, gear ratio, wiring, batteries and speed controllers. The last thing I would want to do with Storm II is offer even more current to the motors. We've also just invested in another complete set of packs for Storm II, so not going to be moving away from them just yet.

However if the A123 supply dries up, and other varients of the chemistry aren't up to the job, then where do we (all) turn.

Big nipper offered to do the trial ages ago now, and they have been in loads of fights and demo's and not had a problem (or a fire)... so come on FRA what else do you want to see?

Like any new technology safety is paramount. LiPos have demonstrated stable operation but only over a limited timescale. The trial in heavyweights only starting in March after all!

Full details will be released once the trials have been completed.

Kane perhaps the FRA could share why that timeline is ?

What are these timelines, where are they published
When does the trial end ?
How long after the end will the FRA publish views

Can we expedite the trial. For example if we are saying we need to run for a year which is 'x' fights, could we ensure that Big Nipper completes the fights sooner, or is the trial based on duration and no relevance to fights ?

Sorry to push, but there appears to be

- no dates published or otherwise
- no published test cases (what is it exactly that is being tested)
- no defined success criteria for what 'good' looks like
- no feedback on how the trial is going
- no detail as to when it will end
- no detail as to when recommendations will be out

I think the roboteers are owed more than a one-liner here

May I ask why Storm II was not invited participate in the Lipo trials?

Seems a bit odd such a powerful all electric machine getting left out. Storm II could actually run a lipo into the ground.

If it's a competition thing, I'm sure Ed would handicap himself back to the A123s. They would be well rested

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Originally Posted by psychostorm

May I ask why Storm II was not invited participate in the Lipo trials?

Seems a bit odd such a powerful all electric machine getting left out. Storm II could actually run a lipo into the ground.

If it's a competition thing, I'm sure Ed would handicap himself back to the A123s. They would be well rested

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The FRA was approached with a proposal from Big Nipper and Robots Live. Roaming Robots have since agreed to allow Big Nipper to run LiPo's at their events.

Guys let's not head off track here, Team Storm never asked to be involved in LiPo trials so that's a total red herring.

However I do think that my questions above around the 'trials' are valid and it would be good to get some feedback in answer to them, perhaps if Kane is ok to defend why Storm II isn't trialling the batteries, he could also provide detail around the trial covering

- no dates published or otherwise
- no published test cases (what is it exactly that is being tested)
- no defined success criteria for what 'good' looks like
- no feedback on how the trial is going
- no detail as to when it will end
- no detail as to when recommendations will be out

That way we know where we stand, understand the aims of the trial and can all assist if there is anything we can do to expedite things.

Please review the AGM minutes. Further details will be announced to FRA members.

I think its defiantly a good time to look at this not only with the A123's supply running out but also the biggest event for heavyweights is this weekend, maybe we can have a sit down on the saturday night and have a talk about the pro's and cons of what people think

This is something that has been discussed repeatedly for several years now. The whole purpose of the trial is to prove the technology is safe for use in heavyweights. If it isn't then it is unlikely to go any further. If it is, and so far no issues have been raised, the rules will be revised at the end of the trial and draft put out for member approval.

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I suspect Bullfrog doesn't show up that issue as it won't push the cells hard.

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The reason they don't get pushed hard is that we just look at what the robot actually would use for a fight and then make sure we are at least on more than that capacity preferably double. As far as the other brand LiFePO4 is concerned, I have not felt any degradation in performance throughout the event. If anything, these cells hold their balance better than the A123's do.

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Big Nipper has been allowed to run LiPo's for a reason, to learn - would be good to share the learning and start to formulate rules to ensure the safe use of them.

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I agree, though as someone who has been using LiPo for over 6 years in other disciplines I would be very surprised if the outcome of the test is anything but With sensible precautions there is no reason not to allow LiPo.

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Originally Posted by Eventorizon

When I spoke with Graeme when he popped over to my university he said that everything was going fine but that they had needed to make a pair of unibody 5mm Alu cases for the Lipos.

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To contain the flames of a bursting LiPo you don't need 5mm ali, a fine steel mesh is enough, as a Davy lamp proves for almost 2 centuries now.
Or the modern equivalent, a LiPo bag or a piece of a fire blanket.
The more annoying white clouds a burst LiPo spreads can be dealt with a sturdy fan and some flexible tubing like this.

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I am not sure what this means for weight but it may be that the safety features required for lipo's may make them almost as heavy as NiCads or SLA's.
The only advantages I can see would be a size reduction and an increase in maximum discharge.
Just a thought...

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Cheaper than high end SLA's too.

Let's just have a few beers in the pub and agree they are ok ! Job done :lol:
A few rules though to be safe .

I'm not sure that we need to view this as a serial process where by we trial, then think, then implement. Having checked out the FRA mins, they say pretty much what I thought they did

3. LiPo Trials

Following sucessful use of LiPo batteries in featherweights a trial of the batteries in heavyweights is being carried out by the Big Nipper team. Due to the inherent dangers of the technology the trials will be closely monitored for review at the year end.

Perhaps we could get some feedback as to the 'close monitoring' referenced and what that monitoring has been, what data/information has been collected (I presume against whatever the agreed success criteria were for the trial ?) - maybe we can as Kenny suggests get a working group together to start to understand what might be required as guidelines for LiPos.

If we learn new things from the trial as time goes by, that can be fed into whatever is being developed - but it seems that an old fashioned approach of doing everything in a totally serial fashion will only drag something out that the FRA has the opportunity to be proactive in. Then when the trial ends, we've already got a solid skeleton of some guidance for temas.

Could I suggest that rather than Saturday evening (when we'll be in the pub) a small working group agree to meet at say 4pm on Saturday. Given the trial is due to end at the end of the year, it doesn't seem unreasonable to start to try to crystalise some thinking on what the guidelines might look like.

... and if all those things that I suggested should be there as part of the trial aren't; we can use that group to understand what we should be looking to get out of the trial - as I assume the 'close monitoring' doesn't just mean we get to the end of a non-determined period and go well that seemed to work ok lol :)

A great opportunity for some progress - who's up for a discussion at 4pm on Saturday ?

yep.

Can I suggest we do it Sunday morning around 10.30am, Saturday may be very busy with sorting robots out etc, and i don't know at what point I will be done with the arena.

Sure Alan if that works better for you !

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Originally Posted by kane

Like any new technology safety is paramount. LiPos have demonstrated stable operation but only over a limited timescale. The trial in heavyweights only starting in March after all!

Full details will be released once the trials have been completed.

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Kane,

I have to say I disagree with you on this one. Lipos have been used in feathers for a long time. Most of the lipos are as big of those wich would be used in heavies and they have to stand up to the impact of spinners. Big Nipper have been using them without major incident and our colleagues across the pond have been using them with a few incidents none of which i believe have resulted in shows being major well prepared shows being stopped or in injury.

We know two things:

1) Most of the time they can be used safely
2) What they do when things go wrong

I simply cannot understand what the issue is. Surely it's a case of looking at how any safety issues are addressed. I can disagree with Mario et al about what the safety issues are, how serious they are and how much provision should be made for them but surely we should just stop faffing around and deal with the issues surrounding them? We don't need a prolongued test to tell us what we already know.

Andy

Oh and the irony of having lipos used in any heavy testing them and not making provision to deal with any issue really does astound me. Are we simply hoping things do not go wrong? With this scenario if we end up with an arena full of smoke where are we expecting it to go?

My opinion they are dangerous and the equivelant of putting a bomb on a robot. That said, a bomb with a safety aspect which can be managed to an acceptable degree. If there was a strict set of rules which made an indicent unlikely and provision for when things go wrong they would be in my robots for the next event.

The biggest change with using LiPo technology in a heavyweight is the current draw. We are stepping up from motors that draw 10-30amps to 100+amps. This puts a hugely greater load on the cells. Early LiPo packs had 10C ratings but the developments mean we can now buy off the shelf packs rated at 50C or more. So the first step is suitability. Experience has shown that LiPo fires are rare and normally only when mishandled such as excessive overcharge. In the event of such an incident this would be handled in the same manner as any fire by the event organiser. Should LiPo technology be approved for use we will also be providing additional guidance for handling LiPo batteries if deemed necessary.

Kane, there are several feathers that draw over 100A on a regular basis. Spinners mainly, but some electric axes as well.
Just like NiCd and NiMH, LiPo batteries should be chosen well for the job they have to do.

Concerning excessive overcharging.
The rules are currently that LiPo's have to be charged in a LiPo bag or simular protective measures.
That is a good measure, and is equal for ants to feathers currently. Extending that to heavies ain't a large efford.

The main issue with LiPo's bursting is the white clouds they emit. For the arena , thats rather easy to solve. For the pits, it's another matter.

On the other hand. How many failed LiPo's did we see at Robot Events events in the Uk?

Exactly, I completely agree!

360 was pulling 260amp 3 years ago... technology has moved on a lot since then.

What was the outcome of the discussion at the HW champs?

A constructive discussion Dave. . . . . .

Main points being?...

Well none I think !

'The main issue with LiPo's bursting is the white clouds they emit. For the arena , thats rather easy to solve. For the pits, it's another matter.'

I believe the smoke is toxic; does anyone know for sure?

'On the other hand. How many failed LiPo's did we see at Robot Events events in the Uk?'

I have not seen any but I was at Robogames in San Francisco in April of this year, where most robots use them and LiPo fires were a regular occurrence. It was a requirement that someone had to be with their robot at all times while queuing for the arena because the previous year a robot waiting for the arena had caught fire with the owner absent. I believe the Robogames arena has a duct to the outside and an extractor fan but fires still involve crew entering the arena and carrying the smoking robot through the hall to the outside where it is opened up and the LiPo pack extracted and buried in sand.