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  1. #1
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    New rechargeable AA Battery Technology

    This link was just posted on the Yahoo Geared Hub Bikes group. Nickel Zinc rechargeable batteries. Output voltage is higher than NIMH or Nicad batteries at about 1.6V though capacity seems lower than the latest NIMH batteries. Only available in AA size so far for consumers. Also use temperature range is more limited, only to 32 degrees F.

    http://www.powergenix.com/consumer.php
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    Senior Member mechBgon's Avatar
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    Very interesting! The first application that came to mind was Cateye LD1100s and LD1000s, since they take AA cells and get significantly dimmer with lower voltages. It would be interesting to see how regulated lights (Fenix L2D, DiNotte AA, etc) responded, too.

  3. #3
    Zoom zoom zoom zoom bonk znomit's Avatar
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    Quote Originally Posted by mechBgon View Post
    Very interesting! The first application that came to mind was Cateye LD1100s and LD1000s, since they take AA cells and get significantly dimmer with lower voltages. It would be interesting to see how regulated lights (Fenix L2D, DiNotte AA, etc) responded, too.
    Yeah my thoughts too, most blinkies are unregulated and do much better with a slightly higher voltage.

  4. #4
    Seņior Member ItsJustMe's Avatar
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    Only good to 32*F makes them useless for most of the time I need my lights the most.
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  5. #5
    Cyclologist Plutonix's Avatar
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    It will be interesting to see what happens as the chemistry develops, but as it stands NiZn is not really a replacement or improvement over NiMH. They have their advantages like being more eco-friendly, higher voltage and high drain capability. They also seem to have a fairly low self discharge rate. But there are also some hefty disadvantages.

    First capacity is very very low: that PowerGenix is only rated at 1350mAh. In what might be called marketing misdirection, most of the NiZn labels are displaying a mWh rating like 2500 hoping you dont read carefully.

    The other con is a very high voltage right off the charger. They say it has a 1.75V freshly charged but many have measured at >1.8 and some (SuperZ) at >1.9V. This could be really bad for something that takes 4 AAs, expecting ~4.8V but getting ~7.2V. Voltage under load drops off more gently than NiMH, but I dont know how long a fresh charged cell needs to rest before voltage falls back.

    Toss in a special charger, and I'll take a pass for now. Given the voltage considerations, they seem more comparable to a rechargable Lithium primary cell (1.5-1.75V) than to NiMH.
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    Plutonix;

    In a power regulated circuit the higher voltage should drop the current draw significantly. Per an engineer's review posted on Amazon, which seems to be pretty knowledgeable, he states that the overall energy capacity is similar to the Sanyo Eneloop low discharge AA cells which are currently rated at 2000 mAH.

    A number of posters there indicate much better life in high current draw regulated circuits such as cameras and photo flash units due to the voltage staying above the unit's cutoff voltage much longer than NIMH cells. Be interesting to see how the new chemistry and technology develop.

    I would think that most AA devices are designed for Alkaline cells with a rated voltage of 1.5V per cell. This makes a 4 cell device expecting 6V rather than the 4.8V you mentioned and reduces the overvoltage you listed significantly.

    Before I switched my Cateye 1100 and PB Superflash lights over to Energizer Lithium batteries for the winter I checked with both manufacturers tech support and neither indicated any known problems with using the Lithiums in their lights with their higher voltage. Both seem to be working fine.
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  7. #7
    Cyclologist Plutonix's Avatar
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    In a power regulated circuit the higher voltage should drop the current draw significantly. Per an engineer's review posted on Amazon, which seems to be pretty knowledgeable, he states that the overall energy capacity is similar to the Sanyo Eneloop low discharge AA cells which are currently rated at 2000 mAH.
    True and False.

    P(ower) = V(olts) * I(Amps)
    So yea, for a given amount of power, if you are working with more volts, you will need fewer amps, so the capacity is depleted in smaller increments.

    However, the voltage to capacity trade off is not proportional.
    Eneloop: 1.2V * 2000mAh == 2400 mWh
    NiZn: 1.6V * 1350mAh == 2160 mWh
    Hi Cap 1.2V * 2300mAh == 2760mWh

    It guess it is kind of similar to an Eneloop (92%) but it doesnt compare to high capacity cells.


    A number of posters there indicate much better life in high current draw regulated circuits such as cameras and photo flash units due to the voltage staying above the unit's cutoff voltage much longer than NIMH cells.
    And for a high demand item like a digi cam (a lot of power in short bursts) I would expect them to do well. It is an application NiMH is ill suited for; the rechargeable nature is the benefit they have over Alkies. Most Bike Lights are not high drain devices though, so they dont benefit much from those advatages. A 4xAA light may be a little brighter with the higher volts, but it cant be brighter AND run as long on 1300mAh than even a set of 2000mAh cells (which are not even high capacity).


    I would think that most AA devices are designed for Alkaline cells with a rated voltage of 1.5V per cell. This makes a 4 cell device expecting 6V rather than the 4.8V you mentioned and reduces the overvoltage you listed significantly.
    You're correct, the baseline would be 6V. Dinotte was mentioned earlier and I had 4.8V stuck in my head from 4xNiMh.

    The Dinotte is apparently designed to be tolerant of the voltage range of NiMh, Alkies and Lithiums (the user guide mentions them all). Thats not true of all 4xAA devices though. Lithiums fried an untold number of cameras which were not prepared to handle the extra volts (the voltage in Lithiums left idle for some time have a tendency to 'steep' like tea and can reach ~1.9V). There used to be gobs of compatibility charts around until the newer cams took Lithiums into account.

    NiZn benefits from that because anything that can handle Lithium voltage should be able to handle NiZn as well. Still, I do recall reports of 2 cell flashlights getting fried from them around June when they first appeared.


    Before I switched my Cateye 1100 and PB Superflash lights over to Energizer Lithium batteries for the winter I checked with both manufacturers tech support...
    I wouldnt expect most 2 cell systems to be bothered, as you are only talking about .5V difference. That said, I fried a Maglite with 2 Lithiums. With each additional cell the difference grows, and even 4 cells devices are probabaly not an issue at nominal voltage. At the extremes, such as Lithiums which have 'steeped' to 1.9V or a freshly charged set of NiZns at ~1.8V, a lot more things are could have problems.

    There is probably a law like that of toast landing butter side down where the more voltage sensitive a device is, the more expensive or critical it is.
    Last edited by Plutonix; 12-03-09 at 12:50 AM.
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