Toshiba laptop battery

B. Short-circuiting
Never attempt to short-circuit a battery. Doing so can damage the product and generate heat that can cause burns.

C. Throwing batteries into a fire or water
Disposing of a battery in fire can cause the battery to rupture. Also avoid placing batteries in water, as this causes batteries to cease to function.

D. Soldering
Never solder anything directly to a battery. This can destroy the safety features of the battery by damaging the safety vent inside the cap.

E. Inserting the batteries with their polarities reversed
Never insert a battery with the positive and negative poles reversed, as this can cause the battery to swell or rupture.

F. Overcharging at high currents and reverse charging
Never reverse charge or overcharge with high currents (i.e. higher than rated). Doing so causes rapid gas generation and increased gas pres-sure, thus causing batteries to swell or rupture.
Charging with an unspecified charger or specified charger that has been modified can cause batteries to swell or rupture. Be sure to indicate　this safety warning clearly in all operating instructions as a handling restriction for ensuring safety.

G. Installation in equipment (with an airtight battery compartment)
Always avoid designing airtight battery compartments.
In some cases, gases (oxygen, hydrogen) may be given off, and there is a danger of the batteries bursting or rupturing in the presence of a source of ignition (sparks generated by a motor switch, etc.).

H. Use of batteries for other purposes
Do not use a battery in an appliance or purpose for which it was not intended. Differences in specifications can damage the battery or appliance.

I. Short-circuiting of battery packs
Special caution is required to prevent short-circuits. Care must be taken during the design of the battery pack shape to ensure batteries cannot be inserted in reverse. Also, caution must be given to certain structures or product terminal shapes which can make short-circuiting more likely.

J. Using old and new batteries together
Avoid using old and new batteries together. Also avoid using these batteries with ordinary dry-cell batteries, Ni-MH batteries or with another manufacturer’s batteries. Differences in various characteristic values, etc., can cause damage to batteries or the product.

Companies specializing in zapping batteries use top quality Japanese-made nickel-cadmium cells. The cells are normally sub-C and are handpicked at the factory. Specially labeled, the cells arrive in a discharged state with an open cell voltages of 1.11 to 1.12V. If below 1.06V, the cell is suspect and zapping does not work well. A low voltage may hint at elevated self-discharge or chemical deficiencies. The 1.1V is produced through the electro-chemical potential of the nickel-cadmium cell. This voltage is present even with no charge. Applying a load would cause the open terminal voltage to collapse.

The secondary battery

Newer chemistries provide higher energy densities than conventional batteries per size and weight but the cost per kWh is higher. This cost is, to a large extent, governed by the number of charge/discharge cycles the battery e.g. pa3356u-1bas can endure.

Primary batteries hold more energy than secondary batteries like pa3384u-1bas per size and weight. Operational readiness, long storage and instant readiness are other benefits. Primary batteries contain little toxic substances and are considered environmentally friendly.

Secondary batteries E.G.PA3107U-1BRS need some level of battery maintenance. Only if periodically discharged do nickel-based batteries provide the cost-effective and reliable service expected in a fleet environment. The deep discharge reverses the crystalline formation (memory) that occurs if a nickel-based battery is repeatedly charged on top of a residual charge. lithium batteries E.G.PA3107U-1BAS  have no memory and an occasional discharge is applied to verify performance. Battery maintenance is best done with a battery analyzer.

Battery aging is subject to cycling, storage temperature and state-of-charge. While a primary battery has a shelf life of 10 years, lithium-based batteries E.G.PA3356U-1BRS are good for 2-3 years in normal use. Cool storage at a 40% charge level prolongs longevity. Nickel-based batteries are good for 5 years and longer but require priming to regain performance after long storage.

Another negative of rechargeable batteries is the high self-discharge. nickel-based batteries exhibit a 10-20% self-discharge per month. This compares with 5-10% for lithium and lead-based batteries. The self-discharge increases at higher temperatures. For this reason, secondary batteries are not an effective media for long-term energy storage; primary batteries are better suited. A secondary battery E.G. PA3383U-1BRS can never be removed too far from the charger. It needs to be fed before each activity.

In the US Army, rechargeable batteries are being used predominately for training. Officials are now exploring their suitability for combat missions. Rechargeables have advantages that go beyond cost issues. For one, the batteries can be re-used and do not burden the supply channels. In the absence of electric power, charging can be done through solar power, windmills and hand-crank generators. Even kinetic power is being explored in which an electric generator is built in the sole of the soldier’s boot. Rechargeable batteries are able to providing power when no supply of fresh batteries is possible.

AC conductance has been incorporated into a number of hand-held testers to check batteries for vehicular and stationary batteries. To offer simple and low-cost units, these testers load the battery with pulses rather than injecting sinusoidal signals. The pulses are commonly not voltage controlled and the thermal battery such as  toshiba laptop battery voltage may be surpassed. The thermal voltage threshold of a lead-acid battery is 25mV per cell. Exceeding this voltage is similar to over-driving an audio amplifier. Amplified noise and distortion is the result.

AC conductance provides accurate readings, provided the battery is fully charged, has rested or has been briefly discharged prior to taking the reading. AC conductance tends to become unreliable on low charge and sometimes fails a good battery e.g. PA3331U-1BRS. At other times, a faulty battery  may pass as good. The correlation to the battery’s state-of-charge is a common complaint by users. AC conductance works best in identifying batteries with definite deficiencies.

This load pulse method does not work well for larger batteries and AC conductance is commonly used. An AC voltage is applied to the battery ,for instance PA3331U-1BRS ,terminals that floats as a ripple on top of the battery’s DC voltage and charges and discharges the battery alternatively. 

AC conductance is non-invasive, quick and the test instruments are relatively inexpensive. There are, however, some fundamental problems. Most commercial testers use only one frequency, which is commonly below 100 Hertz. Multi-frequency systems would be more accurate but require complex data interpretation software and expensive hardware. In this paper we focus on Electrochemical Impedance Spectroscopy (EIS), a method that overcomes some of the shortcomings of AC conductance.

from batteryuniversity.com

The memory effect in batteries if caused by recharging and is hard to avoid. Inside the battery is chemicals that react to combine into a new substance giving off electricity for your laptop in the process. When you recharge your battery you are splitting the newly formed substance back into its original forms.

But each time you recharge it, a little bit doesnt convert back to the orginal form, and this builds up over time. Eventually you will notice that it would hold charge for as long, this is because there is less substances to combine.

To aviod this build up, you can do a few simple things,

1) Dont abuse the fact that it has a battery - If you can run it off the power supply then do so. Run it off the power supply WHENEVER POSSIBLE.

2) If you have to use it on battery, dont just empty the charge say… 25% of the way and then recharge it, use it as much as you can. You dont have to run it flat, but more before recharging is better.

If worst comes to worst and it is significantly decreasing you could always fork out a few $ and buy a new battery e.g. PA3331U-1BRS.