THE 10 MOST IMPORTANT THINGS TO KNOW ABOUT BATTERIES
1. Buy several batteries; like potato chips, one is never enough. With several batteries, some can be charging while others are being used. Also you can fill your pockets with several batteries so that when one dies you have another to quickly replace it.
2. If you shoot infrequently (like once a month or less), use lead acid (gel cells) to power your camera. Gel cells are relatively inexpensive, and once charged, retain their charge for long periods of time without self-discharging. After using a gel cell, be sure to recharge it immediately; if left discharged, the components inside will sulfate and self-destruct leaving you with a useless battery after a couple of days.
3. If you use your camera frequently, use NiCad batteries. They recharge many times, and hold a large amount of current per pound of weight. Most can be "quick" charged within a couple of hours allowing you to keep up as other batteries are used.
Remember that NiCad batteries perform poorly when cold and should not be recharged when very hot or very cold. Handle NiCads gently. Although the exteriors may look fine, concussions can damage the sensitive interior of the batteries causing internal shorts which bleed the life out of the batteries as they sit.
4. Whenever possible, recharge NiCad batteries the day before they will be used. NiCads in good condition generally lose about 2% of their charge per day as they repose on the shelf. Batteries with mild internal shorts drain themselves even faster. A NiCad with a serious short (drains itself dead in one day on the shelf), may still be quite useful to you; charge it immediately before use, then put it right to work. You will drain the power out of it before it drains itself.
5. NiCad memory is a curse primarily of consumer and prosumer gear. NiCad memory is a condition that occurs when you have used the battery for a short period of time and then recharged it, used it again for a short time, then recharged it, and repeated this process a number of times. Eventually the battery "forgets" its original capacity (perhaps 30 - 50 minutes), and only operates your camera for a short period of time (perhaps 10 minutes). The memory is due to a chemical change causing cells in the battery to reduce their voltages by about 10%. Consumer camcorders often have circuits which require 10.5 volts from the 12 volt battery. When the battery goes below this voltage, the mechanism shuts down. If the battery has memory, or one or two cells are weak for some other reason, it is very easy for the voltage to reach the cutoff level causing shutdown. For this reason, consumers and professionals need to "exercise" their batteries, making sure that they perform long duty cycles. There are also devices that discharge and recharge NiCad batteries to exercise them, reducing the memory effect.
Professional video gear is less susceptible to memory problems. Battery packs often contain eleven or twelve cells creating 13.2 or 14.4 volts for a camera that needs only 11 volts to operate. The camera's power circuit uses only the voltage it needs, disregarding the extra. If one cell in a 14.4 volt battery goes awry, there are still 13.2 volts remaining to power the camera. If the NiCad cells develop a memory, losing 10% of their oomph, there are still about 12 volts coming out of the battery pack; the camera remains happy. The battery pack is truly expended when its voltage drops to 11 or so volts.
6. If you use a lot of batteries, team them up with a "smart" charger designed for the batteries (Anton Bauer, Cine 60, Frezzi). These NiCad batteries have sensors to determine whether the batteries are overheating while charging and whether the batteries have reached their full potential. Meanwhile, the smart charger is monitoring each cell's temperature (being careful not to overheat and damage any of the cells), while also monitoring each cell to assure that all get recharged.
7. Rotate your batteries so that some don't do all the work while others sit idle; they all need exercise.
8. The lithium batteries that power many camcorders recharge quickly and appear to have no memory problems but are more expensive than NiCads and Lead Acid Gel Cells.
9. If your gear gets wet, especially in salt water, remove the battery first, and do it immediately. Once the salt water gets into the circuits, there is no way to turn the machine off and it will go into rapid meltdown.
10. Power your lights on a separate battery from your camera. Not only will both shoot longer, but cameras refuse to work with weak batteries, whereas lights don't care. There's no sense having your lights drain off the camera's "good" power, and be able to operate for a half hour more after your camera shuts down.
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