Why rechargeable batteries lower voltage

The only downside on using a smaller voltage battery is that you might experience a shorter operation life. But, anyway, as the battery is rechargeable, that's not a problem. You might need to recharge it more often than replacing an ordinary disposable battery. Hope it helps clarifying the issue. Had same question I tried 1. Go ahead and start using that rechargeable battery it will be a little help to environment.

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Create a free Team What is Teams? Learn more. Mouse rating 1. Ask Question. Asked 6 years, 6 months ago. Active 2 years, 5 months ago. Viewed 15k times. Thank you, Matias. Improve this question. Seven of the nine Star Trek Voyager reference unintentional dropped to only mAh in capacity, and the remaining two were and mAh. Many others have made similar complaints. The following discussion assumes that NiZn's don't suffer reduced capacity early, although that's probably not the case.

NiZn's give either longer, shorter, or fairly equal run time vs. However, devices which don't limit the input voltage like most flashlights and electric toothbrushes, for example will run out faster with NiZn's, because while the device was running the light was burning brighter or the motor was spinning faster. NiZn's will make camera flashes recycle much faster, though burning through lots of flash shots quickly can fry the flash.

That's about half of the best NiMH's. PowerGenix therefore listed the spec on its battery in mWh total energy rather than mAh, because total energy between battery types is more similar, and PowerGenix says that's a more apples-to-apples comparison. That's debatable, from either side. It's true that the total energy is the same, but again, if the device being used doesn't limit the voltage, the device will use the extra voltage and the NiZn will spend its energy faster, so the NiZn's will provide less runtime.

And if the device does limit the voltage, then there's no advantage to using NiZn's in the first place, because the only reason you'd use them instead of NiMH's is if you needed the extra voltage to begin with. The nominal voltage is 1. The higher voltage can be both a blessing and a curse. The upside is that flashlights burn brighter, and battery life will generally be longer in high-drain devices. But there are downsides to the extra voltage. For lights, the brighter light means that the bulbs will burn out faster, sometimes immediately.

Tom's Guide For cameras, a rapid flash cycle can fry the flash. Amazon review For electronics, first understand that some devices have a voltage regulator which limits the max voltage coming from the batteries or a voltage protector which shuts off the device if the battery input is too high.

If your device doesn't have one of these, and the device is very sensitive to voltage, then the batteries might fry it. It's hard to know whether a particular device is a "fry", "auto shut-off", or "no problem" variety. Good luck. The fewer batteries your device takes, the less likely you are to have a problem. Powergenix mostly ignores this problem in their marketing materials, so shame on them.

Self-discharge means the bateries lose their charge by just sitting around, unused. Unlike NiMH's, there is no low self-discharge version available. If you use up and recharge your batteries quickly this won't matter to you.

Like most other rechargeables, NiZn batteries maintain most of their voltage over the whole charge and then suddenly plummet. For this reason many electronic devices that tell you how much battery life is left have a hard time reporting an accurate level for rechargeables, but this is especially true for NiZn's, because their voltage is so high.

You need a special NiZn charger for these cells. NiMH chargers will not work! See below for those who insist trying anyway. PowerGenix made two chargers: the white charger was smart and managed each cell separately, but had only one status LED and it didn't light up until all the batteries were done.

If one cell was bad, the red charge light would blink. Then you got to play musical batteries figuring out which one was bad. The black charger required charging in pairs, and didn't manage the batteries separately. Never buy a charger like that. It's theoretically possible to charge NiZn's with a NiMH charger, but there are at least three problems.

First, even a smart NiMH charger probably won't know when to stop charging NiZN's, and will overcharge, damaging the battery. Second, how will you know when to stop charging? Armed with PowerGenix's recharge profile chart PDF and the battery and charger specs you could make a guess.

I don't know the penalty for feeding more current than is recommended, but a shorter cycle life is my guess. All that said, in a pinch, I've used my La Crosse BC to slightly recharge NiZn's while traveling when I forgot to pack my NiZn charger, but I've terminated the charge well before the cells could be overcharged. I monitored the voltage and took them out when they hit 1.

Even so, at that point your batteries will likely be only about half full. Anyway, all this is at your own risk, of course. Discharged Voltage. The PowerGenix site provides absolutely no guidance as to how far NiZn's should be drained before charging to maximize capacity and cycle life. Shame on them. The typical discharge level for rechargeable batteries is 1. Problems with the charger. NLee says that the charger stops charging when the voltage hits 1. That's not my experience: I had a damaged cell that showed as full at only 1.

NLee also says that batteries left in an unplugged charger will drain times faster than batteries left in other chargers, which means that they'll be discharged after only ten days. NiCads are obsolete rechargeables. NiCd's don't have any advantages over NiMH, and they have lousy capacity and are toxic to boot.

The only reason to use NiCd's is if you already have some—though even then, if you upgrade to a modern battery you won't have to charge them so often. NiCds are hard to find now, but why would you want to?

NiCd's deliver the juice fast enough to power high-drain devices like digital cameras—but not for long, since their capacity is so weak. Different brands have different capacities, but with NiCd it's always low anyway which is why you should be using NiMH instead.

Note that many cheap chargers fill up the D size to only a AA capacity, giving really awful run time. See our recomended chargers. The theory of the NiCd memory effect is that if you repeatedly partially discharge a battery to the same level before charging it, it will "remember" the discharge level and then always fail at that point during use, never allowing the full capacity of the battery to be used. Many observers don't believe that this effect is real, and most of those who do admit that it's hard to reproduce and can be fixed by cycling with a good battery charger anyway.

Now, NiCd's and NiMH's can suffer decreased capacity due to repeated deep-discharging or overcharging, and many people mistakenly blame the resulting reduced capacity on the memory effect. NiCd's discharge quickly meaning they lose charge just by sitting around, unused. For reference, alkalines are 1.

I know that the nominal voltage is just an indication and a typical battery has a declining voltage, e. Not all rechargeable batteries have a nominal voltage of 1. According to Wikipedia, the following rechargeable battery chemistries have cell voltages of 1.

At a glance, it would appear that nickel is the common denominator, but this is not the case, as nickel-hydrogen and nickel-zinc have voltages of 1. Nickel-iron :. Nickel-cadmium :. Ni—Cd cells have a nominal cell potential of 1. Nickel-metal hydride :. A fully charged cell supplies an average 1. In conclusion, the 1. However, every battery chemistry has different characteristics including voltage across a discharge cycle and open-circuit voltage. Each type of battery chemistry yields quite different characteristics, including terminal voltage.

They put a tiny switch-mode voltage regulator in the cap! Of course the conspiracy theorists said the non-rechargeable battery companies were paying the gadget makers to do this deliberately, but the reality is that it's simply been the growing prevalence of low-dropout linear, and switch-mode, power supplies that allows gadgets to work down to much lower cell voltages. Sign up to join this community. The best answers are voted up and rise to the top.