When it’s time to go get fresh “AA” or “AAA” batteries for your electronic devices, there seems to be numerous kinds to choose from: alkaline, ni-cd/ni-mh rechargables, lithium and others. But what is the difference between them and which is the best? Each kind of battery has pros and cons.
Alkaline Batteries: 1.5 volts
- easy to find anywhere
- nearly all electronics accept this battery as they are designed to
- will corrode and/or burst at high temperatures (i.e. leaving them in your car in the summer)
- must be stored in moderate temperatures to last long prior to use
- are not rechargeable
The most common and oldest type of battery is the Alkaline. It was developed back in 1899 and nearly perfected by the 1950s. There have been minor improvements since then but the basic technology is the same. The reason that we are still using alkaline batteries after all this time is that they cheap to make, are energy dense and last longer than most rechargeables. They also let you know when you need to replace them by slowing losing their power over time. The only real downside to alkaline batteries is that they can be damaged by high heat or very low freezing temperatures and don’t work long in these conditions. If you store a flashlight with alkaline batteries in the glove box of your vehicle, they will burst and seep corrosion ruining the flashlight (happened to me). You also cannot store them in extreme temperatures because when it comes time to use them, they may not work at all.
Many of today’s electronic devices can keep track of battery voltage with an internal meter indicating when the batteries need changing. In most cases, these devices are designed to be used with 1.5 volt batteries. Because alkalines are around 1.5 volts at full capacity, they are well suited for any kind of device that needs “AA” or “AAA” batteries and this is why they are still in such wide use today.
Ni-cd and Ni-mh Batteries: 1.2-1.3 volts
- They can be recharged/reused many times
- Good for use in flashlights and transistor radios
- lower than standard voltage means that the more batteries a device takes, the larger the voltage deficit and they may not power the device at all
- only reliable in 2 or less battery configurations due to low voltage
- each charge does not last as long as an alkaline
The lower voltage is the biggest downside to rechargable ni-cd and ni-mh batteries. These also do not keep a charge as long as a new alkaline battery. Even so, rechargeable ni-cd and ni-mh batteries are great for flashlights and radios because they can be recharged many times which means the net usage capability is vastly increased over alkalines. But while ni-cd and ni-mh are both nickel based rechargables, they are not the equal. Ni-cd batteries have what is sometimes referred to as a charge memory. This is a condition where if you don’t completely charge the battery before using it, it will permanently lose maximum capacity and with it already only being 1.2 volts fully charged this is not good. Ni-mh batteries on the other hand do not suffer from charge memory so you can put them on the charger at any time during its discharge cycle without this worry.
Ni-zn Batteries: 1.6 volts
- about the same voltage as Alkaline
- can be stored in high heat with little issue
- can be recharged/reused many times
- Work in most electronics with configurations of 4 or less batteries
- each charge does not last as long as an alkaline
A relitively new Ni based rechargeable, the nickel zinc does not suffer the same issues as other ni based batteries. They are also 1.6 volts being the closest rechargeable to the standard 1.5 volt alkaline. However this can be an issue in and of itself. Having a voltage that is higher than electronics are designed for can cause burn outs of the device. If a device needs 4 alkaline batteries – that is 6 volts (4×1.5=6). However with these you get 6.4 volts (4×1.6=6.4) when charged (or actually higher than that) which can cause even flashlights to overheat quickly. I personally use these with my AA lights but turn the light on low beam and it works fine. If I use high beam with these, the light becomes pretty warm to the touch. However, the fact that I live in Texas and can store these in a flashlight in my truck during the summer with no problems makes it worth the hassle.
Lithium Ion (non rechargeable): 1.5 volts
- all the Pros of Alkaline batteries with none of the Cons
- because of the 1.5 volt standard, can be used in any device that calls for 1.5 volt alkalines
- lasts longer that alkalines
- can take alot more heat than alkalines
- not rechargable
- more expensive than other battery types
The final group of “AA” or “AAA” batteries to cover here are lithium based, specifically lithium-ion batteries. These batteries are unique in that unlike alkalines and nickel based batteries, they are capable of providing a full 1.5 volts until they are almost completely discharged and then they suddenly quit. The lithium-ion batteries last longer than any other kind and are reliable to be used and stored at temperature extremes that would damage or destroy alkalines or the nickel based rechargeables. Lithium based batteries are more expensive than alkalines or nickel based but if you have the money, they are almost always the best batteries to get.
Devices with Built In Rechargeable Lithium Batteries
Most of the flashlights I use today contain a non changeable rechargeable battery pack. Rechargeable lithium batteries run on a different voltage than the AA non rechargeable types. I like these because they fit with my gear and the charges typically last longer. The downside is that when the power runs out, I cant just pop more batteries in the device. I have to recharge it to use it again. However the devices that I use these in run for days before a recharge is required so this has not yet been an issue. They are also capable of withstanding high heat (Texas summers) with no problem.
No matter which kind you choose for your devices, it is always good to store extra new batteries as part of your prepper kit.