Variations in Battery Life

2008.01.16

It's no secret that Neocamera prefers AA batteries over proprietary batteries, as do many other digital camera review sites. There are many reasons for this, including the flexibility they provide, price and availability.

Despite the advantages of AA batteries, a number of people have reported bad experiences with them. That is how I realized the primary advantage of proprietary batteries: their predictability. When you buy a digital camera that requires a proprietary battery, it comes with a brand-new manufacturer-issued battery. That battery was specifically chosen by the manufacturer for that particular camera and the two were extensively tested together. Battery-life was also presumably determined using that same battery model.

Things are different with AA batteries. Some cameras come with disposable Alkaline batteries which rapidly find their way into the trash, while most others come with none at all. Although few manufacturers ship rechargeable batteries, those are the exception. Due to this, people end up testing their new cameras with whatever batteries they find and therefore the millage varies, and it does so greatly...

Here are things to consider when using AA batteries:

• Brand and power matters. Not all batteries are equal. Even though two AA batteries may be specified with the same energy (Say 2500 mAh), some will last longer than others. This has to do with the current they produce as they get discharged. For your information, Maha PowerEx NiMh batteries unscientifically gave me the best results, followed by Sanyo NiMh (not the Eneloop which I did not try).
• New NiMh batteries do not fill to capacity until a few recharge cycles. On average between 6 and 10 cycles (a full charge followed by a full discharge) are required before they reach peak capacity.
• As NiMh batteries get older, their performance diminishes. After a few hundred recharges, they become pretty much useless. Battery-makers generally quote battery-lifespan between 100 and 1000 cycles but results will vary depending on how far a battery is discharged and recharged.
• All NiMh gradually loose their charge when not in use. Most such batteries will not have enough power to operate a digital camera after one month, regardless of their initial charge. That means if you take only one picture each day, you will get a battery-life of 30 or so images. Note that there are now Imedion batteries that claim to keep 85% of their charge after one year.
• Battery life greatly depends on usage. Most numbers are quoted based on the CIPA standard which uses flash 50% of the time and is based on specific timing and other actions such as power-cycling the camera and zooming. Flash and LCD use influence battery-life the most. Those who do not use flash will get a much longer battery-life than the one quoted by the camera maker. Note that movie recording does not fit into this.
• Battery-life also depends on environmental conditions. Cold, for example, reduces battery-life and can cause a camera to be inoperable. Note that freezing batteries is considered dangerous as it can cause internal damage and it is therefore advisable to dispose any batteries which may have frozen.
• Chargers are also important. Many chargers do not charge batteries to their full capacity. Fast chargers generally produce less charge than their slower counterparts. For example, 15 minute chargers usually do not fill the battery to more than 80%-85% of they peak capacity. Due to this, some models of chargers offer two charging speeds. The strategy taken by Imaging Resource is to initially use a rapid charger and follow that by a slow charger to reach peak capacity.

Now, suppose you got the best batteries and charger you can find (and you indeed found good ones). Lets say you also took all the precautions listed above to make sure that your batteries are operating at their best. If you still get battery-life far below that quoted by the manufacturer, then it is time to think the unthinkable: the camera may be defective. If it is still under warranty, get it replaced. You paid for it after all.

• Digital Camera