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AA and AAA Non Rechargeable Lithium batteries

May 28, 2011

You buy a flashlight, insert batteries so it is ready for an emergency, then store it in the closet for a few years. Emergency comes, but does it work? Usually the equipment is ruined by leaking batteries and the flashlight is weak or doesn’t work at all.

You buy a flashlight and it is fancy and rechargeable, so it will be really good in an emergency. You store it in the closet for a few years, and guess what, it is completely dead! Even after a few charges it still won’t hold the charge for long.

This no longer happens to me. Just under 20 years ago I was fortunate enough to purchase a pack of 8 alkaline AA cells, with 2 bonus Energizer (R) AA Lithium cells. These new cells promised to outperform all other non-rechargeable cells by virtue of their unbeatable energy density, but the most important feature of them was not publicised. They last for more than 14 years! Not only that, but if they are partially discharged, they still last over a decade, and they don’t seem to leak!

Every other type of cell I’ve used has leaked once it is left in a partially discharged state, or in the case of rechargeable, if it is not regularly cycled.

I used those original bonus cells in an alarm system and they lasted 15 years. One of the cells still measures 1.5V open circuit now (they are usually 1.8V), almost 20 years later! The others with lower voltages I disposed when I replaced them after their 15 years of service. None of them leaked.

About 10 years ago, when the alarm was still going strong after almost 10 years, I was impressed and I gradually increased my usage of Lithium batteries. This had to be gradual, because they were so expensive. At first I only used them in portable devices, where the light weight of them was a major advantage and worth the extra money in itself. They are 33% lighter than Alkaline (and Alkaline is 33% lighter than NiMH).

The batteries I am talking about are Energizer (R) Ultimate Lithium AA cells and AAA cells. “Lithium-iron disulfide”, “Li/Fe” is the technology, and they are primary cells so must not be recharged.

I began to realise they were so much better in ALL ways. There was no compromise! All other batteries had some sort of trade-off, like NiMh (Nickel Metal Hydride) are super powerful and able to deliver huge currents, but they go flat in a few weeks just sitting on the shelf. They are also damn heavy. Many of the NiMh batteries I used became leaky after about 4 years.

NiCd (Nickel Cadmium) have slightly less impressive power density and have the annoyance of a “memory” so have to be discharged in a way that doesn’t suit anyone’s lifestyle. Many of them also leaked after about 5 years.

Alkalines are a good universal battery and are very cheap so I still use them for some applications, but once they’re a little discharged they seem to leak in only a year or two, which is so destructive to whatever they happen to be plugged into at the time. I have damaged so many devices with Alkaline batteries leaking that I’m fearful of using them in case I neglect to remove them before storage. So I only use them when I know the equipment has no chance of being stored with the cells installed.

Lithium’s are great for “carry around flashlights” e.g. a tiny flashlight powered by a single AAA cell with a powerful LED. For these they simply last longer so they don’t need changing as often.

As mentioned before, emergency flashlights should not use any other technology other than Lithium batteries. You plug in the cells, and leave it in the closet. It is good for 15 years, provided you don’t use it too often and discharge the cells too much.

A surprise to me was the use of Lithium cells in motorized gear. For example, a small beard trimmer. These things often come with a charger stand and contain NiCd rechargeable batteries. They need constant charging and go flat in a few minutes. I purchased a $20 set of clippers 3.5 years ago, and deliberately chose a cheap set which took 2 AA cells. I used Lithium. Guess what? The original set are still going strong with clippers at full speed, and I use the clippers for 30 seconds every few days!

They are also great in gear like an electronic lock with a solenoid. The current is very strong for a short period of time, and Lithium cells seem to love that type of application. If an electronic lock is used rarely, such as in a safe, and the safe has very low standby current, then the batteries could last for years.

Problems and Safety

The largest downside of Lithium dry cells is the price. If you use them a lot, you need to buy in bulk from eBay or win the lottery. Another downside is the end of the discharge curve. The discharge curve starts off great, and carries on nicely with a high voltage for most of the discharge. So the flashlight is bright for hours. BUT it rolls off super quickly when it is near flat. You can basically get caught out with no light. Therefore you need to replace the cells early, or carry a spare set of cells, meaning more dollars.

Lithium’s have such high energy density that they are dangerous to transport, so there are restrictions on cargo on aircraft. Also I wouldn’t let your kids play with them because they are so powerful they would cause serious heat, fire or explosions if they were to short them out or cut them open.

A particular wireless mouse discharged the Lithium batteries faster than Alkalines, I think due to the higher terminal voltage, so I only use alkaline in the mouse now. However in my TV remote control (with learning/programming capabilities) I could get 3 months from the 3 AAA Alkaline batteries. The Lithiums have been in the remote for over a year so far, so already have outdone the Alkaline by 4 times.

Another problem for Lithium batteries is if I leave them loaded in my Zoom H1 recorder. This product reacts badly to the higher voltage and draws vastly more current than it does for an Alkaline. Therefore the Lithium battery will go flat after a couple of days with the device switched off. Alkalines may last for 2 weeks with it switched off. The power control of the device is obviously poorly designed, but it does illustrate a rare example where Lithium batteries should not be used.

All my camera gear, such as flashes and microphones use Lithium batteries. I can trust the expensive equipment won’t be ruined by leaking batteries, even if I don’t use them for 15 years.

I will also mention LiIon rechargeable batteries, which are used in your cell phone. These are particularly good too, with good all round performance, but are a different beast. Unlike the dry cell (primary) Lithium batteries I’ve discussed in this article, they don’t keep their charge for 15 years (only a few months) and in fact shouldn’t be stored for years without using them. I think if you want to store them for > 12 months they’re meant to be discharged first.

Someone searched Google: “is it safe to use aaa lithium batteries in flashlight“. I have been using a carry-around AAA flashlight for about 2 years now and have not had any problems. The flashlight is waterproof so can build up pressure if the cell vents, however I have not heard of flashlights exploding due to this event. Always take care when opening a pressurized vessel by keeping away from other people and wearing eye protection.

I would only become concerned if a high powered flashlight was set to it’s highest power setting and became too hot to touch. Most high quality flashlights purchased from vendors such as 4sevens.com have multiple brightness settings. Generally the brightest setting should only be used briefly since it kills the battery in around an hour or so. I’ve found the flashlights that heat up the most when on their high power setting are the single cell CR123A flashlights.

Disposal

Some Lithium cells are hazardous waste, however I checked the Energizer (R) documentation and it appears to me that the basic AA and AAA cells are OK to throw away in regular domestic waste. I’m not a waste expert so do not rely on me as a reference for this. The documentation says that in the USA the Energizer (R) lithium iron disulfide batteries are RCRA non-hazardous waste. Check with your local government whether you can recycle your Lithium cells.

So next time you win some money, go buy some AAA + AA Lithium batteries and install them into all of your non-rechargeable devices 🙂

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Please leave a comment or tweet to @james00000001. Also see my articles on photography and general technology or politics.
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