Power Express Shop

Part I: Basic Battery Knowledge

Part II: Battery Glossary

Return to Top

2. How do I identify a battery? 

The first information to provide would be the make and model of the equipment that you require the battery for e.g. Toshiba Satellite Pro 400, or Compaq Presario 1283. There is also usually a label on the battery, and some of the information on the label will help our sales team to identify your battery quickly.

This information includes the voltage of the battery pack (note: this is not the same as the voltage on the power supply), the capacity of the battery pack and the chemical construction of the battery pack e.g.Li-ion, Ni-MH or Ni-Cd. This information can be used to ensure the information you have provided matches the information we have about your battery. Many battery packs also have part numbers on the label; this can sometimes be used to help identify the battery. We would suggest that it is best to have all this information written down or close to hand before you call our sales team. This will help us deal with your call in an efficient manner.

Return to Top

3. How can batteries be connected? 

Note: When interconnecting batteries (cells), they must be identical in voltage and amp rating! 

(1) Batteries may be connected in series. The positive terminal of the first battery is connected to the negative terminal of the second battery; the positive terminal of the second is connected to the negative of the third, and so on. The voltage of the assembled battery is the sum of the individual batteries. The batteries are connected: + to - to + to - to + to -, etc. The capacity of the battery is unchanged. 

(2) Batteries may also be connected in parallel. The positive terminal of the first battery is connected to the positive terminal of the second battery, the positive terminal of the second is connected to the positive of the third; the negative terminal of the first battery is connected to the negative terminal of the second battery, the negative terminal of the second is connected to the negative of the third and so on. The batteries are connected: + to + to + and - to - to -. In this configuration, the capacity is the sum of the individual batteries and voltage is unchanged. 

For example, (5) 6V 10AH batteries connected in series produces a battery array that is 30 Volts and 10AH. Connecting the batteries in parallel produces a battery array that is 6 Volts and 50AH. Ordinary auto batteries are designed in the same fashion. Six 2-volt cells are arranged in series to produce a 12v battery. Many Ni-Cd batteries are arranged in the same way.

Return to Top

4. What are the ratings for battery?

V(olts): The voltage of the new battery should always match the voltage of the original.

mAh: It standards for milli-Amp hours (1 mAh=0.001Ah), High amp-hour rating means a longer run-time and will not cause incompatibilities.

Return to Top

5. What is a battery cycle? 

Cycle life is measured by the amount of times a battery may be charged and discharged. Every time a battery is charged and discharged, it uses one cycle. Cycle life is very important in battery applications such as laptop batteries and emergency light batteries. A Ni-Cd battery has a cycle life of 500-1000 or more cycles.

Return to Top

6. Does it really help to store batteries in the refrigerator? 

Yes, but only if they can be kept dry as well. The higher the temperature, the more the free flow of ions or self-discharge from the battery. Storing primary batteries (D's, C's, AA's, AAA's, 9 volt, etc.) in a cooler environment slows down this rate of discharge that all batteries experience even when not in use, hence a longer shelf life. However, if this is done, it is important that the batteries be kept as dry as possible by keeping them in an airtight container in the driest part of the refrigerator, the door side for example. Long time exposure to moisture inside the refrigerator can cause internal corrosion to the battery. When removing batteries from the refrigerator, allow them to warm up to room temperature before using them in your device.

Return to Top

7. Can I use my old version Ni-Cd battery chargers to charge my Ni-MH batteries? 

No, you can use a new Ni-MH charger to charge your old NiCD batteries but you should not try to charge Ni-MH batteries with a NiCD charger. 

Here's why: Ni-MH and NiCD batteries are chemically very similar and when both are fully charged the battery voltage will start to drop. The Ni-MH voltage drop is much more subtle and more difficult to detect. Ni-MH chargers usually have an overheating sensor and shutoff to prevent overcharge as well as a more sensitive voltage drop detector where NiCD chargers usually only use the voltage drop to determine when to stop charging. If you charge Ni-MH batteries in a NiCD charger it will probably miss the voltage drop and keep right on charging causing the batteries to overheat. Overcharging and overheating Ni-MH batteries can damage them internally and reduce battery life.

Return to Top

8. What is the difference between a LI ION battery and a NI MH battery?

"LI ION" stands for Lithium Ion and is the most advanced battery technology available to consumers today. Li-Ion batteries are 50% lighter than the NI MH (Nickel Metal Hydride) batteries and will run your device about 50% longer. They are, however, more expensive.

Return to Top

9. What are Amps, volts and Run Time?

Every battery has two ratings which are volts and amp-hours (AH). The Ah rating may also be given as milliamp-hours (mAh), which are one-thousandth of an amp-hour ( for example, a 2Ah battery is equal to 2000mAh). Ah hours are a rating of the amount of energy that a battery can store. Typically, the mAh rating is also a measure of the number of hours a battery may last. For example, a 2000mAh battery will last at least 2 hours. The higher a battery's amp hour rating is, the longer the battery's run-time will be. It is not uncommon for some of our batteries to have higher or lower amp ratings. This will not cause any incompatibilities.

Voltage ratings, however, must be within a reasonable range. For instance, your original battery may say 3.6v, but you purchase a battery that is 3.7v. This is still acceptable. The rule of thumb when dealing with voltage is to never exceed one volt higher than your original rating. So if your original battery is rated at 3.6v, then you would be able to use a replacement battery up to 4.6v and nothing higher.

Run times vary for many reasons, such as the type of device, the type of applications being used, whether or not you are playing a cd or dvd and the chemistry of the battery. The average computer should give you between 1.5 to 3 hours of run time. Once again, this varies for many reasons.

Return to Top

10. Can I upgrade my device's battery to a newer chemistry?

Ni-Cd, Ni-MH and Li-ion are all fundamentally different from one another and cannot be substituted unless the device has been pre-configured from the factory to accept more than one type of rechargeable battery. The difference between them stems from the fact that each type requires a different charging pattern to be properly recharged. Therefore, the portable device's charger must be properly configured to handle a given type of rechargeable battery.

Please refer to your owner's manual to find out which rechargeable battery types your particular device supports, or simply use our search engine to find your device. It will automatically list all of the battery types particular device supports.

Return to Top

Part II: Battery Glossary

Battery: Two or more cells connected together  

Cell: An electrochemical system that converts chemical energy into electrical energy.

Capacity: This is amount of energy a battery cell or battery pack actually provides. The higher the capacity the longer the equipment will run on battery power. Usually measured in Amp hours (Ah) or Milliamp hours (mAh). 

Battery Charge: This is the process of passing electricity into the battery pack so the pack can be used to provide power when the user is away from mains power

Li-ion: Lithium Ion. This is one the newest battery types available. It can offer the same power as a Ni-MH battery in a smaller & lighter package. This type does not suffer from 'Memory Effect' but it is expensive to manufacture.

Ni-Cd: Nickel Cadmium. This is one of the oldest battery technologies that are still in use. Usually found only in older equipment or applications that require a high power drain. Very prone to 'Memory Effect'.

Ni-MH: Nickel Metal Hydride. This battery type has virtually replaced the Ni-Cd batteries. This type offers higher capacities, around 30% more than a Ni-Cd cell of the same physical size. This type is also reported to suffer less from 'Memory Effect'.

Battery Float Voltage: A unit for measuring electrical pressure. All batteries provide DC (Direct Current) electricity. It is important to ensure that the equipment you are powering is being provided with the correct volt or else damage may occur.

Return to Top