Are rechargeable batteries worth the extra up-front cost, and if so, which type is best?
Because there are many different types of batteries and battery uses, there is no one answer to these questions. But I can make a few recommendations that will help you. This guide focuses on standard consumer batteries—the AA, AAA, C, D and 9V batteries you typically put in your portable devices and toys. There are three main considerations:
2. Performance for a given application, and
3. Environmental friendliness.
I am going to give you a bunch of important "battery answers" right up front:
1. Yes, rechargeable batteries make economic sense in most cases.
2. Nickel-metal-hydride (NiMH) are the best rechargeable batteries you can get from several standpoints, including performance and low toxicity for the environment.
3. Although today's disposable alkaline batteries can be thrown in the trash, all rechargeable batteries should be recycled.
But there's a little more to rechargeable batteries than that, so I hope you'll read on. I want you to get the most possible benefit from your new rechargeable batteries, and there are a few pieces of information that will help you do that.
Rechargeable batteries almost always make economic sense. The upfront cost of setting yourself up with rechargeable batteries and the charger may seem off-putting at first, especially when you realize that you'll want to have some extra batteries that can be recharging while you're running devices like your Walkman, wireless computer mouse, and battery-powered toys.
Let's walk through a cost analysis by considering the following scenario. Say you have a few different devices that use AA batteries, and you want to be able to have a total of eight batteries to power them at any given time. You also want four spares that can be charging while the other batteries are in use.
The total cost for this scenario—12 rechargeable batteries plus the charger—will be about $65.00. That may sound like a lot of up-front spending when you consider that you can buy an 12-pack of quality disposable AA batteries for around twelve bucks. But if you're like most households and it seems like every other trip to the store finds you buying another 12-pack of throw-aways, then rechargeables will definitely be the better deal.
For instance, under the scenario above, if you're now buying a eight-dollar 8-pack of batteries every month, that's a yearly cost of $96. After less than a year, your $65 initial investment in the rechargeable setup will be paid for, and the next 10 years of battery use will be free. Over that period, you would save nearly $1000! And it will be 1,000 fewer disposable batteries going into your nearby landfill .
If you don't use that many batteries—say a couple of 8-packs per year—you could still actually save money over the long run with rechargeables, though that would depend on the types of uses. But rechargeable batteries make the most sense for devices that get heavy to moderate use and have a high to medium current draw. These are the devices you find yourself changing batteries for at least once a month, or every couple of months at a minimum.
Which type of rechargeable battery is best?
There are several types of rechargeable-battery chemistries:
Nickel-Cadmium (Nicad) batteries - usually pronounced "ni-cad" - are a primary form of rechargeable battery, though they are being used less these days because of the toxicity of cadmium.
Nickel-metal-hydride (NiMH) batteries are probably the most common form of rechargeable now, at least in the standard consumer sizes of rechargeables. Early versions of NiMH rechargeables had problems with too-rapid discharge, but those problems have been solved in current models bit is still the one drawback to them. Because NiMH rechargeable batteries now perform better than Nicads and are free of toxic heavy metals, Nicads are being abandoned by some manufacturers in favor of NiMHs. In any event, NiMHs are usually going to be the best all-around choice for most applications in the heavy to moderate usage range.
Instant Rechargeable Batteries (NiMH) can be used straight out of the pack as they lose very little charge from the time they leave the factory to the time you take them off the shelf. They will retain 70% of their capacity over 12 months compared to standard NiMH batteries which lose about 1% per day. They are better for low drain devices such as remote controls and transistor radios.
Very low self discharge rate, meaning one can charge them any time, store them until needed, and then use them.
Because of the previous characteristic, the manufacturer sells them pre-charged, so one doesn't have to charge them before their first use.
Lower internal resistance, meaning higher voltage reaching equipment that uses high currents (such as digital cameras).
One disadvantage of the Instants over normal NiMH cells is lower capacity. For the AA size, Vapex claims a capacity of 2500mAh. Normal NiMH AAs are available with capacities of up to 2900mAh nowadays, but when you consider self discharge rate, such NiMH cells stored for about 30 days will drop to 2000mAh.
Lithium-ion batteries are very good and have excellent shelf life—i.e. their charge does not go down when they're just sitting around not being used—but they're more expensive than other types of rechargeable batteries. That means they're usually only a good choice for occasionally used emergency devices or high-drain devices like portable televisions, digital cameras, laptops, and cell phones. If you use such devices often and you have the option to buy them with a built-in lithium-ion rechargeable battery, it's worth doing.
You should be able to get hundreds of recharging cycles out of all of these types of batteries