Re: Cell Phone Safety

I'd be emabarrased to have my cellular company's names connected with
this absurd collection of material.... I hope this is a joke?

Overcharging -  Overcharging shortens battery life. Also it is best to
let the battery completely discharge periodically before recharging
(this applies to all rechargeable batteries).

http://www.batteryuniversity.com/partone-23.htm
How to charge - when to charge table (BU14A)
(Li Ion)

"No, it is better to recharge more often; avoid frequent full
discharges.
Yes, on batteries with a fuel gauge, allow a full discharge once a
month to enable reset"

http://www.batteryuniversity.com/partone-12.htm
Charging lithium-ion batteries (BU12)
"
There is only one way to charge lithium-based batteries. The so-called
'miracle chargers', which claim to restore and prolong batteries, do
not exist for lithium chemistries. Neither does super-fast charging
apply. Manufacturers of lithium-ion cells have very strict guidelines
in charge procedures and the pack should be charged as per the
manufacturers "typical" charge technique.

Lithium-ion is a very clean system and does not need priming as
nickel-based batteries do. The 1st charge is no different to the 5th or
the 50th charge. Stickers instructing to charge the battery for 8 hours
or more for the first time may be a leftover from the nickel battery
days.

Most cells are charged to 4.20 volts with a tolerance of
+/?0.05V/cell. Charging only to 4.10V reduced the capacity by 10% but
provides a longer service life. Newer cell are capable of delivering a
good cycle count with a charge to 4.20 volts per cell. Figure 1 shows
the voltage and current signature as the lithium-ion cell passes
through the charge stages."


 
Figure 1: Charge stages of a lithium-ion battery. Increasing the charge
current on a lithium?ion charger does not shorten the charge time by
much. Although the voltage peak is reached quicker with higher current,
the topping charge will take longer.

The charge time of most chargers is about 3 hours. Smaller batteries
used for cell phones can be charged at 1C; the larger 18650 cell used
for laptops should be charged at 0.8C or less. The charge efficiency is
99.9% and the battery remains cool during charge. Full charge is
attained after the voltage threshold has been reached and the current
has dropped to 3% of the rated current or has leveled off.

Fire Danger! - Turn the phone off while putting gas in your car. Exxon
Mobile has issued warnings to business's about this potential danger.
Explosions have happened because of cell phone's igniting the gas.

http://www.snopes.com/autos/hazards/gasvapor.asp


Claim:   Cellular phones have touched off explosions at gas stations.

Status:   False.

Examples:

Batteries - They can explode! Especially lithium batteries. They will
react with water. They literally catch on fire instantly! Another good
reason not to keep them in your pocket!

I'm not a chemist, but this faulty logic is not hard to spot.
Interesting thought process to come up with this one... Lithium is a
reactive metal but lithium -Ion batteries AFAIK are not made from
mettalic Lithium.Lithium Ion batteries must contain lithium. Pure
mettalic Sodium catches fire in water, releasing hydrogen gas. Sodium
is even more violent than Lithium.
Since lithium batteries catch fire, then they also must react violently
with water...
Lithium batttery fires appear by overheating and flammable gases, not
the reactive of any lithium in the battery and water. I've washed a
number of lithium batteries.


Here's the difference between Lithium ion and Lithium Ion Polymer..

http://www.batteryuniversity.com/partone-5.htm


Nutralizing gases in Li-Polymer batteries by soaking in salt water is
recommended.
It's also recomened to wash the electrolyte off with water below....

http://www.helihobby.com/html/disclaimer.html

"12. Dispose of cells or battery packs as follows:
a. Discharge: with the cell or battery pack in a safe area, connect a
moderate resistance across the terminals until the cell or battery pack
is discharged. CAUTION: the cell or battery pack may be hot!
b. Discard:
- NiMH: place in regular trash.
- NiCd: recycle (cadmium is toxic).
- Li-Po: puncture plastic envelope, immerse in salt water for several
hours and place in regular trash."

http://www.wired.com/news/technology/1,68631-0.html

www.megatech.com/images_5.0/ instructions_manuals/lithium_safety.doc -
LITHIUM BATTERY SAFETY ***

"Please be sure to read and follow these instructions carefully.
Safety in using Polymer cells or assemblies is your first priority.

If you cannot comply with the safe handling of Polymer cells or
assemblies then do not use them. 
If you do not understand the
characteristics of Polymer cells or assemblies then do not use them.

Safe Charging 
Lithium Polymer cells have very strict charging
requirements. 
Always charge Lithium Polymer cells or packs with
recommended charger or great damage may occur. 
Always use chargers
specifically approved for Lithium Polymer cells or packs. 
Always
test your charger to assure it is functioning properly. 
Always
charge your Lithium Polymer cells or packs outdoors and in a fire proof
container. 
Always store Lithium Polymer cells or packs in a fire
proof container. 
Always have sand or dry fire extinguisher handy in
the event of fire. 
Always keep any battery out of the reach of
children. 
Always handle Lithium Polymer cells and packs with great
care. 
Always purchase a factory authorized built pack instead of
building your own. 
Always observe the correct polarity when
connecting cells or packs to charger or application. 
Always seek
medical attention if electrolyte gets in your eyes (flush with cold
water immediately). 
Always scrub with soap and water if electrolyte
comes in contact with your skin..."

-
Dave

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