Here is the scoop on the nickle-zinc batteries

[Larry (IL)]

It seems to be two disadvantages to the higher terminal voltage AA batteries, NiZn, one is fully charged batteries might be 1.85 Volts each before settling down to 1.65 which might be too high and cause damage. Two, the life expectancy is one half to one forth that of other rechargeables, maybe only 200 charges before going kaput. Luckily, they are not all that expensive, about $25 for 8 batteries and two chargers. Here is the longer version:



The batteries are the new Nickel-Zinc rechargeable AA cells. The greatest selling feature of NiZn cell is its higher terminal voltage. The nominal operating voltage of NiZn is 1.65V, which is very close to alkaline and 30% higher than NiMH (1.25V nominal). However, when freshly charged, the NiZn terminal voltage is around 1.85V, which is dangerously high for most battery-operated appliances.

Upon closer examination, many of the alleged benefits of NiZn turn out to be just marketing hypes. For examples:

"Higher Energy Density":
Despite what the confusing rating on the package ("2500 milli-WATT-hour") may suggest, the PowerGenix AA cell does NOT contain more energy than a SANYO eneloop AA cell. This is because its current capacity is much lower at just 1500 milli-Ampere-hour (based on data sheet of PowerGenix AA cell, and verified by my own testing).
- Energy in eneloop AA cell: 1.25V * 2000mAh = 2500mWh
- Energy in PowerGenix AA cell: 1.65V * 1500mAh = 2475mWh


"Long Cycle Life":
PowerGenix claims that NiZn has a service life that 'meets or beats' that of NiMH cells. But according to technical data found on PowerGenix web site, the NiZn cell is only rated for 200 cycles at 100% deep discharge. Most NiMH cells are rated for 500-1000 deep discharge cycles.

 

[HuntinDog]

Boy, I think I like the short version.
TMI

Cheap sale batteries for me...

Thanks for the research Larry.

HH

 

[srf2112]

Jeez Larry, It's like you're a schooled expert on the subject . . .oh yeah you are. Thanks for giving us the low-down so the rest of us not so expert people can weed through the hype. Much appreciated . .

 

[floridason]

Hi Lary/Nancy/IL, Yeah Larry, thanks a lot for your info. Good stuff. Christmas, a year ago I found a SALE on New RAYOVAC - Alkaline batteries ( 2- 30 batt packs for the price of 1) that was 60 batts for $10.00. So I bought and got 120 batteries for 20.00 minus my Military discount (10%) + state tax and the batteries are good to 2016. I not only use them for my MXT's, but for other things. My MXT's go for a long time and when they get down to 8v out put I change'em for new ones. I thiink I got a pretty good deal on'em and their the best I've come across yet for long satisfying power requirements. The best IMHO. HH All.

 

[jamesinwesttexas]

Thanks Larry. So am I right in concluding that I should avoid NiZn rechargeables but the Sanyo NiMH AA 2500ma rechargeables are about the best rechargeables to use in the MXT and that you still prefer any cheap alkaline to the rechargeables? James

 

[Larry (IL)]

If I were to try rechargeables, I would try the NiZn because of the higher terminal voltage. The NiMH will only give 10 volts fully charged while the NiZn will give you 12.65. Even with the lower 200 charges life expectancy, that is only 12 cents per charge and that includes the price of the chargers. Replacement batteries are $12 for 8 of them which reduces the cost to 6 cents per charge.

For the MXT I think the NiZn would be the way to go. Any rechargeable battery will not last as long as alkalines but if you do a lot of hunting, I think rechargeables will save you money in the long run.

 

[jamesinwesttexas]

That clears it up, thanks Larry.
James