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

[widow_twanky]

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.

[kane]

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.

[maddox10]

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?

[kane]

Exactly, I completely agree!

[Mouldy]

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?

[teamstorm]

A constructive discussion Dave. . . . . .

[Mouldy]

Main points being?...

[terry]

Well none I think !

[john_frizell]

'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.