How long will my AA nickel metalhydride rechargeable batteries last? How long before they do not take or hold a charge? The ones that I have seem to be discharging more rapidly with non-use. maybe they are also not lasting as long with use, but I am not sure of that. Thanks.
Hi, Unfortunately nickel metal hydride rechargeable batteries retain a memory, If you want to get the best results from them, you will have to discharge them one by one with an amp metre if you have one or use a 12 volt bulb to drain them off. Then re-charge on a 14-hour charger, don’t use the 5-hour quick charge for the first time after draining. Paul
Paul: Thanks. It is not that big a hassle or that big a price to replace them. I didn't want to recharge them and then get someplace with no camera because the batteries were gone. They seem to be doing okay right now; I will just keep going along until it seems too fast a discharge. Should I replace them all at once when I do replace them? BTW, I do have the 5 hour quick charge type.
I'm having similar problems that my metal hydride are not holding their charge, I was under the impression metal hydride did not retain a memory like the nickel cadmiums?
I was under the same impression regarding memory effect in NiMH batteries when compared to NiCd. As for how long they should last, that's related to the mA/hr rating of the battery and the current draw of the item they are used in. It's best to keep in mind rechargeables and non-rechargeables (Li-Ion and Alkaline) have different drain characteristics. Also, rechargeable batteries do not hold their charge indefinitely with the charge draining off slowly. Hence, the time they take to discharge below a certain threshold (the usable level of current supply at the rated voltage for the item they are used in) is shortened the longer the period between charge and use. Still, Paul's suggestion of draining them fully with a lamp (I have a 4x AA torch I have for work I use to drain my AA NiMH batteries fully) and slow charging is good housekeeping for rechargables. Also, I believe any battery suffering memory effect can be shorted to another battery of lower voltage to 'break' the memory then slow charged to recover. Just a couple of thoughts....
I stopped using these types of batteries as the "memory" thing is actually a myth. The rechargeables have their purpose but won't last as long as Alkaline batteries when that is what is more important and being able to reuse them. Today I use Energizer E2 and recently took several with me on a long Eurpoe trip and never had to change out the new ones I put in after nearly 400 photographs with a mix of flash and nonflash. There was not enough power left for the download though. Just take a few 4 packs and you will have more power than you will need.
My camera uses four AA size batteries. I use NiMH as I understand they do not suffer from the memory thing as do NiCad ones. I always carry a set of four fully charged ones with me, but the ones in the camera last for ages, so I rarely have to change them, except on holidays. I could never get that performance from NiCads. I think modern cameras are much less power-thirsty than earlier ones.
NiMh batteries have a higher 'self discharge" rate then the old NiCad batteries but do not have the old memory problem of Nicad... so it is best to charge them often and use them after a fresh charge. NiMh batteries also come in much higher mah ratings as high as 2200mah where the Nicads are much lower. All in all Nimh are better batteries. I understand that it takes 100 or mor charges for them to loos capacity. They are also sensitive to over sharging if you use a fast charger and can "vent" if they get too hot. (dead battery)
I'm using lithium batteries in my new digital- I haven't explored the possibility of rechargables yet, but with the type of lithium battery I use going for close to 10 bucks a pop, I may do so. The manual that comes with my camera says not to use alkaline batteries- would there be any reason not to do so?
I have a Fuji Finepix S602Z, and they tell me not to use lithium, manganese, or nickel cadmium batteries. Compatible batteries are AA-size alkaline (4) or AA-size Ni-MN (nickel-metal hydride) batteries (4). What kind of camera do you have that says no alkalines? Ron
"The nickel-metal-hydride battery Research on the nickel-metal-hydride system started in the 1970s as a means of storing hydrogen for the nickel hydrogen battery. Today, nickel hydrogen is used mainly for satellite applications. nickel hydrogen batteries are bulky, require high-pressure steel canisters and cost thousands of dollars per cell. In the early experimental days of nickel-metal hydride, the metal hydride alloys were unstable in the cell environment and the desired performance characteristics could not be achieved. As a result, the development of nickel-metal hydride slowed down. New hydride alloys were developed in the 1980s that were stable enough for use in a cell. Since then, nickel-metal hydride has steadily improved. The success of nickel-metal hydride has been driven by high energy density and the use of environmentally friendly metals. The modern nickel-metal hydride offers up to 40% higher energy density compared to the standard nickel-cadmium. There is potential for yet higher capacities, but not without some negative side effects. Nickel-metal hydride is less durable than nickel-cadmium. Cycling under heavy load and storage at high temperature reduces the service life. nickel-metal hydride suffers from high self-discharge, which is higher than that of nickel-cadmium. Nickel-metal hydride has been replacing nickel-cadmium in markets such as wireless communications and mobile computing. Experts agree that nickel-metal hydride has greatly improved over the years, but limitations remain. Most shortcomings are native to the nickel-based technology and are shared with nickel-cadmium. It is widely accepted that nickel-metal hydride is an interim step to lithium-based battery technology. Here is a summary of the advantages and limitations of nickel-metal hydride batteries. Advantages 30-40% higher capacity than standard nickel-cadmium. Nickel-metal-hydride has potential for yet higher energy densities. Less prone to memory than nickel-cadmium - fewer exercise cycles are required. Simple storage and transportation - transport is not subject to regulatory control. Environmentally friendly - contains only mild toxins; profitable for recycling. Limitations Limited service life - the performance starts to deteriorate after 200-300 cycles if repeatedly deeply cycled. Relatively short storage of three years. Cool temperature and a partial charge slows aging. Limited discharge current - although nickel-metal-hydride is capable of delivering high discharge currents, heavy load reduces the battery's cycle life. More complex charge algorithm needed - nickel-metal-hydride generates more heat during charge and requires slightly longer charge times than nickel-cadmium. Trickle charge settings are critical because the battery cannot absorb overcharge. High self-discharge - typically 50% higher than nickel-cadmium. Performance degrades if stored at elevated temperatures - nickel-metal-hydride should be stored in a cool place at 40% state-of-charge. High maintenance - nickel-metal hydride requires regular full discharge to prevent crystalline formation. nickel-cadmium should be exercised once a month, nickel-metal-hydride once in every 3 months." for further information see - http://www.batteryuniversity.com/index.htm Milne
