Are LiPo batteries safe for HW robots?

[widow_twanky]

My main concern would be fire load.

It's ok to say they hardly ever explode but simple fact is the potential is still there for them to do so.

Using Hydra as an example where we had a short on the Nicad battery packs. It was realtively easy to deal with with very little heat or flame except very locally to the packs. It was easy to pick up and run out of the building with and it was realatively easy to keep cool whilst we got the packs out (one went first and then with a cascade effect took out the others and tried to set them on fire too). That said they didn't stop trying to catch fire again until out of the robot and completely taken apart from their mounting brackets.

In the event that someone has a large lipo in their robot it has potential to explode. It happens before you know about it and then you are dealing with a fire rather than smoke. If there is more than one pack in there and one explodes what do you do? Do you go in and fight the fire in the full knowledge that there is a further pack in there which may explode or do you leave it and contain it and risk it spreading and burning down the arena and sports hall? (and worse disrupting the show!!)

IMO there are safer packs to use and absolutely no reason for anyone to take a risk on LiPo's in heavies.

Andy

[leorcc]

First off, A lipo cause a burst fire, that is hardly an explosion. These fires create a violent flame but die out very fast as well, as the the chemical fuel runs out. That being said I see no good reason to put Lipo in a heavyweight other than a weight advantage.

I think as LiFePo4 develops, the market for LiPo will steadily die out. Batteries need to become more stabile, and in the power to weight ratio LiPo wins for the moment, but that difference will decrease as production and research improves.

[grant_ploughbot]

Leo, although your 100% right about the safety side of lipo's, i dont think the A123 or similar technology will be catching up any time soon.
The new range's of lipos that are beginning to hit the shelves now are getting seriously good. 40C continous and 65C burst ratings! in a 6000mA pack that featherweights can easily use would mean 240A continous, and 390A burst. In a 6s (equivilent to 24v) pack, you would be able to run a good amount of heavies with a battery pack that weighs about 800g, and fit in the smallest space . If your robot cant contain a fire from a lipo for 30-40 seconds, then it shouldnt pass a tech check with one in!

[grant_ploughbot]

Oh just forgot - check out these new Hyperion Lipos..... http://www.fast-lad.co.uk/store/hype...r /> <br /> 5C

[leorcc]

Leo, although your 100% right about the safety side of lipo's, i dont think the A123 or similar technology will be catching up any time soon.

We'll see about that.

[Mouldy]

We'll see about that.[/quote]

The point is.. Lipos with amazing spec's are already availible. Hence i use them. why wait for a123's that might not be as good in the future?

Imagine what a robot such as tiberious could do with lipos considering it currently runs on SLA's.. he would be saving about 10kg.. Thats 10% of the weight allowence of a heavyweight. The possibilities to improve upon todays current machines is huge.

[cliveb]

We'll see about that.

The point is.. Lipos with amazing spec's are already availible. Hence i use them. why wait for a123's that might not be as good in the future?

Imagine what a robot such as tiberious could do with lipos considering it currently runs on SLA's.. he would be saving about 10kg.. Thats 10% of the weight allowence of a heavyweight. The possibilities to improve upon todays current machines is huge.[/quote]


Exactly god knows what he would do with an extra 10kg, Sam has caused me enough pain in the last 12 months as it is.

[leorcc]

We'll see about that.

The point is.. Lipos with amazing spec's are already availible. Hence i use them. why wait for a123's that might not be as good in the future?

Imagine what a robot such as tiberious could do with lipos considering it currently runs on SLA's.. he would be saving about 10kg.. Thats 10% of the weight allowence of a heavyweight. The possibilities to improve upon todays current machines is huge.

Where in my posting have you seen me make a judgement on the use of LiPo's in heavies one way or the other? I am stating what I see as the future that Lipo will phase out as LiFe or similar chemical compounds will improve and give a better and more stable. Grant is of another opinion. Neither opinion has anything to do with weighclasses.

As for why wait? If you don't need the extra weight, SLA is still a lot cheaper option than LiPo or LiFe. If you do need the extra weight advantage, there is weight to be saved with A123 too, so instead of calculating how much weight you save from SLA to Lipo, calculate how much weight you save from LiFe to Lipo. That difference is a lot less shocking as you make it out to be.

[m2xt]

Perhaps it's time for the FRA governing body to stop precluding technology that is generally available and legal to use. What the FRA should do is make recommendations for or against the use of a technology and possibly impose conditions of use if justified (assuming they have the knowledge to make an informed view). Risk of fire, well IC engines and petrol is allowed so what is the greater risk? For me, it is down to the EO to decide along with the venue hosts what can and what cannot be used surely?

[craig_anto]

Exactly Paul