Powergenix 1.6-Volt Nickel-Zinc AA Rechargeable
Finally, a rechargeable battery that delivers as much juice as disposables. PowerGenix took high-power-producing nickel-zinc chemistry, typically too short-lived to be useful, and increased its life span 10-fold by using a water-based electrolyte that doesn't dissolve the vulnerable zinc. Now it lasts up to 1,000 charges, as long as any other rechargeable, while putting out 1.6 volts, beating current 1.2-volt rechargeables and matching the 1.5-volt throwaway alkalines that most gadgets are designed for.
I long ago stopped reading Popular Science because it was obvious that most articles were written by people who had no understanding of whatever they wrote about. This blurb is an excellent example.
The "juice" put out by a battery is rated in mAh (milliampere-hours), not volts. These cells' mAh capacity is not stated, neither here nor on the PowerGenix site, suggesting that it's nothing to write home about.
As to the voltage... Most (not all) battery-opearted equipment is designed to work "acceptably" at 1V/cell. (This is a leftover from the days of carbon-zinc cells, which declined pretty quickly from their nominal 1.5 volts.) Nicad and NiMH cells have a fairly constant voltage of 1.2 to 1.25 volts, which is fine for almost any equipment. The voltage does not matter as much as the ability to deliver current at a low source impedance, which both Nicad and NiMH cells can do.
As for "water-based" electrolytes... Most electrolytes are water-based. Your car's battery uses a water-based solution of sulphuric acid.
These cells might very well represent a major breakthrough. But you'd never know it reading about them in Popular Science.
You can download spec sheets at the powergeix website (under "Technology").
For the AA cell type, it says:
1500 mAh typical, 1350 mAh minimum
Since most articles have URLs with them where one can get additional info, being short on information is no biggie.
The batteries are shown as having 2,500 mWh, which when calculated at the 1.6V comes out to 1,562.5 mAh. With the higher voltage it actually makes sense to show the wattage rather than the amperage, as the overall power available is of prime importance.
I found the information interesting enough to check out Powergenix's website and found a review that stated that tests allowed them to get 300 to 400 flash pictures per charge, whereas regular AA NiMH batteries gave at most about 200.
Going to Amazon from there, I picked up a combo of 4 AAs and a charger for about $23.00 delivered price.
Even though PopSci sometimes screws up (and I haven't found any magazine that doesn't), I find most of the info they supply good enough to determine whether I want to check things out further on the web.
Importantly, they supply information on upcoming technologies that otherwise might stay below my radar.
While it would have been nice to have that info included in the article, crimue is right, the info is there, and 1350 mAh isn't half bad.
IddiKlu is right about 1.6 V cells having proportionally more power than a 1.2 V cell with the same charge (charge in the sense of Coulombs, measured in mAh). However, many devices will waste the extra voltage as heat because they have internal voltage regulators that cut the voltage down to a specific level or current mirrors to ensure the current draw is correct. For instance, the luminosity of an LED flashlight depends only on the current going through the LED and any excess voltage is wasted in the resistor or transistor regulating the current. Many electronics also use integrated circuits who draw a specific amount of current to operate, with the current often increasing with higher voltage. 1.2 V cells might last longer than 1.6 V cells for this reason.
charvak and IddiKlu both have good points. Note however that it isn't voltage alone that determines how much power you can get out of the cell. The voltage x mAh is a measure of energy, not power. The amount of power you can get out of the cell is limited by the cell's internal resistance and its open circuit voltage. These cells have a high open circuit voltage and claim to have a low internal resistance. Both are good for supplying a lot of power. Although some devices waste any extra voltage, these days, most electronic devices do not. Most modern electronic devices, such as digital cameras and flashes, use switching power supplies that take full advantage of the extra voltage provided by these cells. In fact, any white LED flashlight that runs on fewer than 3 cells must be using a switching power supply because the operating voltage of a white LED if more than 3 volts. On the other hand, if you use these in are regular incandecent flashlights they'll shine brighter and whiter than when using NiMH but you will probably burn out the bulbs a lot faster because these have a voltage that is actually higher than a normal battery and filament life is a very strong function of voltage.
I do wonder just how good these cells are though because their specs aren't very specific. For example, I'd like to see a graph on how quickly they self discharge and, are they really free of any memory effect? Why don't they make them in the AAA size? I bought a set to try them out and they have worked well so far. They are in a few devices that quit after a very short time with NiMH cells because they require more than 1.2V per cell to operate. If these are great, they have done a poor job marketing them.
Because of my arthritis, I use battery operated "massagers" fairly frequently & it is **very** hard to get them to operate as they do in the stores - as stores almost always use disposables for the extra voltage. Even the relatively minor drop from 1.5v/cell to 1.2v/cell ends up being a total voltage drop from 6v to 4.8v for most of these massagers. The level of power output thus goes from an effective relaxing pulse to something significantly less effective. Depending on the device, it can even reduce it to an ineffective, annoying buzz. Using a massager can then become much more expensive AND pretty environmentally wasteful if the only way to make it worth using is to buy disposables.
This may not seem like a useful comment if you think it's only for people with disabilities that cause pain, but these massagers have more than one purpose, and, in fact, combatting arthritis is probably the less frequent use for such massagers. ; ) Popsci is written mainly for men, but other women may want to know that these batteries have made my devices **much** more effective at provoking relaxing muscle contractions. Although the duration one can use these is also reduced by the increased voltage (same energy, but delivered faster means less duration), my favorite massager could go for more than 4 hours on my previous rechargeable batteries (energizer 2300mAh), I find the 2+hour duration more than satisfactory w/the Powergenix.
In general (I mean, moving beyond the world of massagers), the volt boost is not necessarily important in every type of device. Some applications other than massagers, though, can benefit. Consider:
Garage door openers get more range - and unlike other batteries w/ self-discharge rates that are high, these batteries can last months before needing re-charge.
Camera flashes - The number of flashes is based on total energy - which is Watts * Amps. Thus the low mAh rating is terribly deceptive. In fact, for a flash, this is the best rechargeable possible because the lag-time between flashes is entirely dependent on the voltage. Because of the higher voltage, these batteries will allow you to take more pictures per minute while getting the same number of flashes per battery recharge. Nothing is better than Powergenix for flash attachments.
Flashlights - if your flashlight, like nearly all flashlights, shines brighter with fresh batteries, then your flashlight will literally provide more light with Powergenix than with other batteries...even brighter than with non-rechargeables. Since the recharge time is quite short with this charger and the batteries hold their charge a very long time when stored in a drawer, unless you're stuck for a very long time without other light *and* without a way to recharge, these may be better for your flashlights. This one is a preference thing, and those with excellent low-light vision may opt for longer duration at dim brightnesses, but most people would choose the bright light for an hour or two over a dim light for 1.5 to 3 hours.
So... think about it when buying batteries. If you've ever wished your device, whatever it is, had more **strength/power** the way that I've wanted out of my massagers, then gals, this is the battery for you. If low-energy staying power is more your thing, then other batteries might be better.