New Batteries?

**fwsorg** · 1st January 2004, 14:21

Right. Intrigued by this Lithium Battery witch hunt, I consulted my triton charger hand book. When I oponed the box, the first thing that dropped out was a sheet of A4 with Important warning concerning the use of li-ion and li-poly cells Stating that The Li-io/Li-poly chemistry is a very volatile mixture. Misuse can quickly result in Li-ion/Li-poly cells getting hot, exploding, or igniting, which could lead to serious damage or personal injury. When I got the charger out, there was a sticker on it saying exactly the same thing. When I oponed the instruction manual, which details how to charge the types of batt that the triton can charge- Nicad, Nimh, Li-ion, Li-poly, SLA etc, under the Li-ion/Li-poly section, it says right at the top, in bold Important warning concerning the use of li-ion and li-poly cells Stating that The Li-io/Li-poly chemistry is a very volatile mixture. Misuse can quickly result in Li-ion/Li-poly cells getting hot, exploding, or igniting, which could lead to serious damage or personal injury.

I get the impression the triton manufacturers are trying to tell me something. I then spoke to some folks at Sussex Model Centre. The conclusion was the same. Whether or not the explode when you look at the, as some ppl seem to be claiming, it is clear that they are more dangerous than the other battery types, and whilst we all strive to be as careful as possible with our batteries anyway, extra care should be taken when using these.

As a bare minimum, ensure all your li-ion/li-poly batts have obtained UL1642 approval (quality of construction) and I would say you also want to ensure it has a built-in protection circuit. When draining this things quickly, and charging them, there is a much much greater risk of them exploding than there is with Nicads or Nimhs and so on.

As with most things like this, ensuring you use the safest and best practise (and I would be dubious as to whether or not use in a fighting root is safe practise) then there shouldnt be a problem.

Happy new year,

Eddy

**leorcc** · 1st January 2004, 14:52

True, and as one of my friends whos into RC boat races will tell you, a lot of NiCad packs have entered the water without a boat during events.

On some occasions even more than inside a boat.

**ewan** · 1st January 2004, 16:42

I was simply saying before, that if they fell off a pallet etc, AND it shortcircuited, Like what happened in my laptop accident, that then bad things could happen. But I do aggree that for fuse protected Li-Ions, the chance of them shortcircuiting is VERY low.
I think that Li-Ions may come into use someday for robots, but the technology needs to evolve to cater for high current needs etc.
THE END

1st January 2004, 19:02

The reason In my opinion why Li-pos are slightly more lightly to get damaged is that they do not have a super though outer shell like a ni-mh/ni-cd/sla etc. The shell on them is some thin foil type thing. This helps to keep the weight down but does not make them as secure.

Li-po technolegy has come along way. The first came with soft bendable tabs now the tabs are pcbs. They first came with no safety warnings now they do. It was like when ni-cds came out first. People did not know how to treat them correctly hence alot of fires. Now people know how to treat Ni-cds we see alot less fires.

In my opinion Li-pos are where Ni-mhs were about 3-4years ago. Now look at Ni-mhs. The new Gp 3300cells have almost the same current handelling capabilities as the 2400mah Ni-cds. Things are constently advancing.

But as i said it is possible to use them but I dont have to money to use them nor do most people.

As for if a li-po gets punchered. Well its simple you get a bucket of water and add salt then chuck the battery into the bucket for 1-2days then just throw it in the trash.

Every battery is dangerous. I got a 3rd degree burn from a 700mah 4.8v Ni-cd battery when it shorted. In featherweights now people are using 24 and 36v 2400mah ni-cds the short circuit current is much higher. We have to respect batteries. If you dont you will get hurt. As they say if you play with fire you will get burnt. If we treat all our batteries nicely we will never have a peoblem. If you dont then you do so at your own risk. One of the antweight guys who is an electronic engineer told me he got a really bad burn from a AAA alkaline. Most of us would class this as a safe thing as it never crosses our mind what they can do.

Regards
Ian Mc Donald

1st January 2004, 23:37

Well, heres examples of both sides of the arguement:

http://www.rcstuff.us/battery/lipo/lipo_DNA.htmlhttp://www.rcstuff.us/battery/lipo/lipo_DNA.html

http://www.robotwars101.org/~robotwars1/phpBB/viewtopic.php?mode=viewtopic&topic=94&forum=1&star t=330http://www.robotwars101.org/~robotwa...iewtopic&topic =94&forum=1&start=330 (3rd post down)

We need some industrial standards to refer to.

**robotic_ants** · 2nd January 2004, 03:28

**ukrobotics** · 13th January 2004, 13:17

Ed - It is true that lots of portable consumer devices such as MP3 Players, PDAs and Mobile phones do use Li-on/Li-po technology and they are indeed classed as non spillable. But they are certainly more volatile than most other battery types, and there have been quite a few fire/explosion incidents - especially in mobile phones:

http://www.theregister.co.uk/content/68/33828.htmlhttp://www.theregister.co.uk/content/68/33828.html
http://www.theregister.co.uk/content/68/33879.htmlhttp://www.theregister.co.uk/content/68/33879.html
http://www.theregister.co.uk/content/68/33990.htmlhttp://www.theregister.co.uk/content/68/33990.html

It seems that overcharge,internal failure and short circuit are more likley to cause a li-po/li-on battery to fail, rather than impact.

As far as robot use goes they should be fine, if they do happen to explode or catch fire, better if it happens in an R/C metal box than while in your hand pressed against the side of your head!

Ewan - If your laptop hit the floor hard enough to damage the battery, id be more concerned about the state of the hard drive.

Dominic

http://www.ukrobotics.comhttp://www.ukrobotics.com