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

[teamstorm]

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

[maddox10]

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.

[terry]

Big nipper has had Lipo in for the last year.

[maddox10]

Big nipper has had Lipo in for the last year.

That demonstrates the as far as I know.

[PJ-27]

Why the dependance on one brand of Lithium Iron Phosphate?

[teamstorm]

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.

[craig_colliass]

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.

[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.
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...

[teamstorm]

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

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 !

[Ellis]

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..