Batteries : The 'Popular Science' Fact Sheet

[feryl]

I'm guessing that most photophiles here are interested in battery technology, so here's a ripped factsheet from Popular Science magazine about the different types of batteries we have.

Alkaline Disposable

They still exist because of convenience, not chemistry: You can buy them - for a pittance - from NY to Nepal. Perfect for occasional use devices, such as smoke detectors and TV removes, because oftheir long shelf life.

Nickel-Cadmium

Good for 1000 discharge cycles. They're toxic and suffer 'memory effect', when damaged crystals form if the cell isn't fully discharged. NiCds are rare except in power tools; their high discharge rates suit big-current draws.

Nickel Metal Hydride

Higher energy density than NiCds but only lasts up to 500 discharge cycles. Must be fully discharged monthly to preserve strength. Leading chemistry for rechargeable AAs and other standard cells. Relatively non-toxic.

Lithium Ion

Unbeatable for energy density. Up to 1000 discharge cycles without memory effects, so don't require discharging. Currently the leading chemistry for laptops, camcorders, cellphones and portable gadgets.

Lithium Ion Polymer

Variation on Li-Ion chemistry introduced in 1999. Solid, polymer innards of cell allow designers to mold battery into odd shapes so that they can squeeze it around components, maximising capacity.


Courtesy of Popular Science October 2004

 

[hwchoy]

I am interested to know where I can dispose/recycle batteries properly in Singapore.

 

[jsbn]

There's one place - rubbish bin.

Its sad but it seems dat the recycling movement isn't very strong here. Want to find a recycle bin oso difficult.

 

[Astin]

There is also a major difference between alkaline and Nicd/NiMH. Alkaline battery generate power (technical term "discharge") gradually, meaning the voltage drops from 1.5V slowly & gradually to 0V. (ie 1.5>1.4>1.3>>>) On the other hand, Nicd/NiMH battery generate power evenly for the start, abt constant 1.2V, then will suddenly drop to 0V, like a sudden death.

Some electrical equipment can function at low voltage, such as torchlight/alarm clock, while some equipment can ONLY function at higher voltage, such as digicam, electric screwdriver.

 

[Drudkh]

Nice facts/info you guys have provided. But I'm stil puzzled on why in general, batteries still can power up for a while after sometime it went flat? :think:

 

[Astin]

To generate power, u need voltage and current. Any electrical/physics student knows that

In layman terms, you need a high voltage to kick-start a electrical equipment, then u need the current to keep the equipment running. Eg to keep a lens zoom motor moving, to keep the LCD light up, etc.

Inside battery, it is basically a pool of chemical (water-like). This chemical store a charge. When u connect the head and the tail together, the chemical will release the charge and become energy. When you recharge, the chemical will re-store a charge again.

 

[hwchoy]

dun think that is what drudkh is asking.

 

[Astin]

Chemical reaction, need help from chemical engineer/chemist to explain.....

 

[feryl]

Well, the Popular Science article i have does explain but it's all chemistry to me (i'm more of a biology person...). So anyone interested can go to any bookstore and read the magazine article.

 

[Firefox]

There is also a major difference between alkaline and Nicd/NiMH. Alkaline battery generate power (technical term "discharge") gradually, meaning the voltage drops from 1.5V slowly & gradually to 0V. (ie 1.5>1.4>1.3>>>) On the other hand, Nicd/NiMH battery generate power evenly for the start, abt constant 1.2V, then will suddenly drop to 0V, like a sudden death.

NiCD/ NiMH actually starts off at around 1.4v per cell then rapidly drops to 1.2v constant discharge before a steep drop to extremely low voltages.

 

[sehsuan]

I am interested to know where I can dispose/recycle batteries properly in Singapore.

for recycleable NiCD/NiMH/LiOn batteries, we can dispose of them at Nokia Care Centres. I remember reading about it in such a letter addressed to ST Forums

 

[xray]

I am interested to know where I can dispose/recycle batteries properly in Singapore.

The NEA person who came to my sch today to talk about recycling says that there are no recycling facilities for batteries in Singapore. Nearest is in Malaysia.

 

[Zerstorer]

There is also a major difference between alkaline and Nicd/NiMH. Alkaline battery generate power (technical term "discharge") gradually, meaning the voltage drops from 1.5V slowly & gradually to 0V. (ie 1.5>1.4>1.3>>>) On the other hand, Nicd/NiMH battery generate power evenly for the start, abt constant 1.2V, then will suddenly drop to 0V, like a sudden death.

This is not correct. Nimh are 1.4V+ when fully charged, they will slowly taper off when discharging till about 1.1/1.2V when they are almost depleted. This is why battery sensors cannot accurately gauge the charge level of Nimh batteries as the voltage gradient isn't steep enough.

A NiMh doesn't ever goto 0V, if it drops below 1V it will already suffer damage due to deep discharge.

 

[moos blues]

Question.

How do I drain my NiMh batts...


I shoot with sanyo 2300s in a420EX, but cant wear out the batts in one seating... how do u guys drain them...? tried putting them in a torch and leaving it on... damn it, they take damn long to drain... I want to drain them before the next charging...

Right now i'm considering using the batts over a few shootings and using normal AAs as back up... hemmm....sigh.. no my charger got no refresh function.