Will your rechargeable battery die an early death?

Keeping your batteries healthy
by Bob Carlson

Batteries are a frequent source of problems for portable video, audio and computer equipment, and, unfortunately, there's a lot of misinformation out there about how to take care of them. Just to set the record straight and help you get the most out of your investment, I thought you should know...

• Not all rechargeable batteries are the same. There are two types commonly used in today's camcorders: nickel cadmium (ni-cad) and lead acid. Small electronic devices, such as palm-sized camcorders and cell phones, typically use ni-cads, and full-sized camcorders usually use lead acid. It is important to identify which type you have before charging or storing them.

• Ni-cad batteries should be totally drained before recharging. This type of battery is notorious for developing a "memory." If you frequently use the battery for 15 minutes and immediately recharge it, then it may soon run only 15 minutes, even on a full charge. It is better to leave the battery partially discharged between uses unless you will store it more than a few days. For longer storage, run the battery all the way down, then recharge it before storing. Ideally, a full discharge and recharge should occur on a regular basis, such as once a month.

• Lead acid batteries, on the other hand, should be recharged immediately after use. This is crucial! If they are stored partially or totally discharged, they may never recharge again. This is true even if you use them for only 10 minutes. Fully discharging them can actually shorten their life.

• Gradual capacity loss. All types of rechargeable batteries lose power capacity with time. Lead acid batteries can be recharged roughly 500 times with slightly less usable power each time, but even unused they can lose up to 20% of their capacity each year. Ni-cad batteries can be recharged roughly 1,000 times, losing capacity with each charge, but again, even unused they can lose as much as 10% of their capacity each year.

• Remove the battery when storing. Some camcorders drain batteries even when turned off. Not all models are designed this way, but it does occur. Some camcorders will use automatically use the installed rechargeable battery to power the date/time circuits and other memory functions when it is present, even though these circuits normally draw power from separate backup batteries installed by the user. This drainage will discharge your battery completely in a few months and can destroy lead acid batteries. It is good practice to always remove your battery before putting away your camcorder.