After studying a range of specifications for digital cameras currently on the market, it would seem that the majority specify 4xAA cells (i.e., 6 volts) as the power source. Some cameras suggest the optional use of rechargeable cells such as four Nickel Cadmium (NiCad) cells, or four Nickel Metal Hydride (NiMH) cells. Each of these cells has a nominal voltage of 1.2 volts, so a pack of four would supply 4.8 volts. Rechargeable cells would certainly be more economic in the long term, and more convenient.
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After studying a range of specifications for digital cameras currently on the market, it would seem that the majority specify 4xAA cells (i.e., 6 volts) as the power source. Some cameras suggest the optional use of rechargeable cells such as four Nickel Cadmium (NiCad) cells, or four Nickel Metal Hydride (NiMH) cells. Each of these cells has a nominal voltage of 1.2 volts, so a pack of four would supply 4.8 volts. Rechargeable cells would certainly be more economic in the long term, and more convenient. I am puzzled how a camera which is obviously designed to operate at 6 volts could operate effectively at 4.8 volts. What effect does the lower voltage have on performance of the electronics, the LCD screen, flash, and motor drives such as zoom lens, shutter and aperture controls. Are these cameras really designed to operate at 4.8 volts and tolerate the over voltage when equipped with four alkaline cells (6 volts ); or do they give diminished performance at 4.8 volts. Surely a fluctuation from 6.0 volts to 4.8 volts must have some effect on performance ? Regards,
Mr F.Scott (via email) Dear Mr Scott Lead acid and alkaline AA batteries are designed to work at voltage levels between about 1.5 volts and well under 1 volt, so when you use four of them together, the maximum voltage achievable is, as you say, six volts while the minimum is under four volts. Engineers who design digital cameras allow for this range when specifying the performance of any electronic components that are driven by battery power. There should be no loss of functionality when using rechargeable cells as their voltage is well above the cut-off limit. Incidentally, this cut-off point can vary slightly between devices so you could find that one camera will operate on batteries that won’t allow another model to even switch on. From a practical viewpoint, a big advantage of using rechargeables is that despite their lower maximum voltage, they maintain a higher voltage level for quite a bit more of their charged-up state than non-rechargeables. When they do cut out it is generally quite sudden, so there is little chance of danger to devices that use them. Non-rechargeables, in contrast, lose voltage more gradually and can end up in a transition state in which their voltage is marginally usable. (I don’t know whether this could damage a camera, although I suspect that with better-designed models the designer would set the cut-off point for running the camera at a voltage level that would be compatible with the camera’s electronics). Rechargeable NiCds have another advantage: they hold their charge better than lead acid or alkaline cells and so give better performance when used in flash units. In our camera tests I’ve found there are many models (especially at the upper end of the price/quality range) that use newer (and generally more efficient) battery types, such as rechargeable lithium ion and NiMH cells. The former tend to be purpose-designed for a specific model or group of models, while the latter are often AA size batteries similar to those available through supermarkets and chain stores. I don’t recall testing any digital cameras that use lead acid batteries; most manufacturers specify alkaline or NiMH cells as a minimum requirement. Cameras using non-rechargeables tend to be more common at the lower end of the market – although, interestingly, Olympus often produces cameras that are designed for rechargeables but can accept AA alkalines or compatible lithium batteries as well as rechargeable NiCds or NiMH cells. Their rationale is that these are usually easy to come by when your batteries run out while you’re travelling or on location. Some of these cameras are supplied with non-rechargeable batteries, others with rechargeables and a charging unit. The latter approach pushes up the price quite a bit, so you need to factor in the cost of buying a charger and set of rechargeables when doing price comparisons. I hope that has answered your questions. Best wishes with your digital imaging.
Margaret Brown
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