For new NiMH batteries, it is often necessary to cycle them at least three to five times before they reach peak performance. Battery cycling can be achieved simply by using the batteries as you normally would and then recharging them.

At room temperature, NiMH batteries, without usage, will self-discharge in around 30 to 60 days, depending on environmental condition. In other words, if you leave the batteries on the shelf for more than 30 - 60 days, you should recharge the batteries before using them. It is normal for batteries to be fully depleted of power after long term storage. The number of times you can recharge your batteries will depend on the operating parameters, such as drain rate, battery care, etc. In general, under desirable conditions, NiMH batteries can last up to 500 recharges. In absolute best conditions, NiMH batteries can last up to 1000 recharges.

My camera came with 1600mAh Batteries.  Can I still use 1800mAh Batteries or will they hurt my camera by being to strong?

You can use the 1800 mAh batteries.  1800mAh denotes the capacity of a battery, not it's strength.  Capacity is how much charge a battery holds once it is fully charged. The more capacity, the longer a battery will last in any given application.  Voltage is the strength. Rechargeable batteries actually develop around 1.4 to 1.45 volts when fully charged even though they are marked as 1.2V.

Capacity; NiMH batteries are rated in "mAh", acronym for "milli-ampere hours". This number tells you how long the batteries can last under a certain power consumption. The higher, the better, for this number.

Memory is a type of problem that traditional NiCD batteries usually develop. You probably have heard that in order to maintain the life and performance of rechargeable batteries, you have to fully drain the batteries before recharging them. Thanks to "memory free" technology featured on NiMH batteries, you can charge them anytime you wish, regardless if the batteries are fully drained or not.

Recently the market has introduced a new type of supposedly affordable rechargeable alkaline batteries. However, they do not compare with NiMH rechargeable technology. The key difference is that rechargeable alkaline batteries can be recharged up to 50 times. NiMH can be recharged up to 500 times. 

* Cell information and specification varies from brand to brand

For NiMH batteries, the shelf life at room temperature is about 70 to 90 days. If you are seeking for longer shelf life, you may wish to consider alkaline or non-rechargeable lithium batteries, which are commonly used for memory backups.

battery symbols and terminologies.

"mAh": Stands for milli-ampere hours. It measures the capacity of the batteries. For example, a 1000mAh capacity means that the batteries will last for 1 hour if subjected to a 1000mA discharge current.

"V": Stands for voltage. It measure the power of the batteries. For NiMH batteries, they are 1.2V. For alkaline batteries, they are 1.5V. 

"C": "C" defines the rate at which a battery is charged or discharged. It is the capacity obtained from a new battery subjected to a constant-current discharge at room temperature. For example, draining a battery at 1C means to drain the capacity of a cell completely in one hour. Likewise, draining a battery at 0.2C means discharge a battery in 5 hours. For nickel-metal hydride cells, the rated capacity is normally determined at a discharge rate that fully depletes the cell in five hours, or 0.2C.


 NiMH batteries can reach as high as 130 degrees during a charge cycle. The amount of discharge and of course the rate of charge will affect this.

1. Do not close the cover ( if your NiMH Battery Charger has one ) while your batteries are charging. It is best to allow any heat to dissipate as much as possible. 
2. You also may wish to use a small fan to help keep the batteries cool, and prevent excessive heat build up during charging.

Newer NiMH battery chargers are designed to specifically charge NiMH and NiCD chemistries. However most of the older NiCD chargers were not designed to charge any other battery chemistries such as NiMH since they were unavailable at that time these chargers were designed. That is why many of the newer NiMH/NiCD chargers are capable of automatically charging both types, while others have a switch. There is more than just mA ratings involved when charging different battery chemistries (rate of charge, length of charge, type of charge. etc...) While it is true that some NiCD chargers can be used to charge NiMH batteries you must consider the following points if you decide to attempt to charge your NiMH batteries using an older NiCD charger.

1. Improper charging or using a charger that is not specifically designed to charge any rechargeable battery can cause their useful life to be shortened dramatically or in some cases actually damage them permanently.

2. Although a NiCD charger may seem to be charging NiMH batteries fine, this is not usually the case. NiMH chargers are specifically designed to prevent Hydrogen bubbles from forming on the battery plates and of course to charge them to their full potential.

Basically you should always use the type of charger recommended for your type of batteries.