| Doug McLaren wrote:
| > | The Natural Philosopher wrote:
| > | > Bob Monsen wrote:
| > ...
| > | Here is a link describing the problems fedex has had with them:
| > |
| > | http://www.findarticles.com/p/articles/mi_qa3864/is_200505/ai_n13642120
The link may concentrate on LiPo/LiIon cells, but the statistics given
clearly show that most of their battery incidents involve _other_
sorts of batteries.
| > From your link --
| > In the past several years there have been incidents involving lead
| > acid (20), NiCd and NiMH (4), lithium primary (5), lithium-ion (1),
| > and dry cell (8) batteries.
| > So, from the numbers, which battery sounds the most dangerous? Which
| > battery sounds the safest?
| Are you really trying to argue that nicad packs are as dangerous as
| liion or lipo packs? The article above is talking about both primary and
| secondary cells.
Not exactly. What I was saying was clarified shortly after. You even
quoted it --
| > Granted, these figures do not mean that lead acid batteries are 20x
| > more dangerous than li-ion cells, but only that they (it's not really
| > clear who `they' is, however) had 20x the problems with them recently.
My point has been through this entire thread that all batteries are
dangerous. Battery danger is NOT confined to LiPo or Li-Ion
In fact, lead acid batteries have many of the same dangers as LiPo
-- damage them, and they release acid.
-- overcharge them, and they release hydrogen gas -- explosive.
Far far more people have been maimed by exploding lead acid
batteries than by lipos.
-- discharge them too far, and they'll damage themselves.
(Especially if you don't recharge them quickly.)
-- Make sure you use the proper charger, or you'll damage the
battery and could cause a fire.
| > We are all pretty much aware of these instructions.
| Even people who are asking what the best rechargable battery is, like
| the OP?
You were responding to me. Think of my `We' as the `editorial we'.
| There are recently documented cases of exploding cellphones
I'm aware of the cases. I even mentioned them in the thread.
However, they weren't exploding. Just burning. (Though I guess any
fire that starts in your packet is going to be called an explosion.)
| and spontaneous laptop combustion, which are directly attributable
| to mishandling lithium secondary cells. I can't remember a similar
| widespread problem caused by nicad or nimh batteries.
That's because when you short out a NiCd cell and start a fire, that's
called a fire started by a `short circuit'.
When you short out a LiPo cell and start a fire, that fire is
attributed to those `dangerous LiPo cells'.
But don't worry that NiCd and NiMH cells aren't burning up their share
of R/C planes -- they are.
| As I've continued to assert, these batteries are safe, but one must
| simply take more care in using and charging li-ion and li-poly batteries
| than nicad or nimh batteries.
And I've been asserting that NiCd and NiMH cells are dangerous as
well, and require similar care to be taken.
| > | My little hitec charger puts more than 3C into a 600mAH nicad pack
Ahh, I misunderstood what you were trying to say. It's good that
you're not really putting 3C into your pack.
| > | It's a fire hazard for liion, and possibly lipoly packs,
| > | particularly homemade packs made from free cells.
| > Where did this bit of wisdom about homemade packs come from?
| As I understand it, commercial packs which are designed for comsumer
| devices are required to have current limiting electronics built into
As Red said, you will not find these electronics in R/C power packs.
It doesn't matter if they're homemade or commercial.
You short it, you may start a fire. Same goes for NiCd and NiMH
Doug McLaren, email@example.com
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