Q1. Tell me a bit more about rechargeable batteries, how are they different from primary or throwaway batteries?
Rechargeable batteries are of the same sizes (AA, AAA, C, D, Sc and 9V) and are intended for everyday use are the throwaway or primary batteries people use. The advantage of rechargeable batteries is that they can be recharged and reused up to a thousand times and generally they greatly outperform standard everyday throwaway leading brand batteries. The fact that rechargeable batteries can be used again and again represents a massive saving over their useful life. Once charged, these rechargeable batteries can be used in the same way as you would with your previously throwaway batteries of the same size.
Q2. What does battery "mAh" capacity mean?
The mAh capacity rating refers to the storage capacity available for a particular battery. A battery with a capacity rating of 1800 mAh could deliver a current of 1800mA for one hour. Higher mAh ratings for the same battery type will generally mean longer run times. This does not apply when comparing different types of batteries. This means that you may not be able to predict how long your electronic device will run just by looking at the capacity rating of a battery. When powering high drain electronic devices like digital cameras, computer peripherals, or portable music players, an alkaline battery will only deliver a small fraction of its rated capacity. For example AA alkaline batteries typically have a capacity rating of over 2,500 mAh and AA NiMH batteries have rated capacities of only 1,200 to 2,000 mAh. But when it comes to actually powering an electronic device like a digital camera, the NiMH batteries will often run the device for three or four times a long. Even comparing the capacity ratings of similar types of batteries won't often work since different manufacturers can measure battery capacity in slightly different ways. A NiMH or NiCd battery is likely to deliver much closer to its rated capacity when it's powering high drain devices. Alkaline batteries have a high rated capacity, but they can only deliver their full capacity if the power is used slowly. This means that a NiMH battery with a rated capacity of 1200 mAh can take many more photos than an alkaline battery with a rated capacity of 2,800.