Breakdown Flashlight: Alkaline vs Lithium

[AlaskaMoose]

I think a lot of people are confusing lithium with the more common rechargeable lithium-ion batteries found in consumer devices. They have different chemistries, and have different characteristics that give them different pros and cons. Primary cell lithium batteries have very high energy density and extremely long shelf lives compared to alkaline and lithium-ion batteries, which makes them ideal for emergency devices like flashlights.

I use a SureFire P3X Fury that I keep in my car all the time. It's incredibly compact compared to a Maglite, being not much thicker than a highlighter. Most SureFire flashlights are also pretty short (the P3X shown below is longer than most because it uses three batteries rather than two, like most fullsize SureFire models).
View attachment 2078221

All good, but while lithium batteries pack more energy than alkaline batteries they are more expensive. To me it makes no economic sense to buy a rechargeable lithium battery flashlight to keep in in the trunk of my car. I would still have to partially charge the batteries perhaps once per month (maybe every two months) to account for the natural discharge rate of the battery. But regular alkaline batteries are relatively cheap and aren't affected by the high temperatures as much as lithium batteries if left in the car's trunk during a hot summer. Lithium batteries don't take high temperatures well, so 113-degree temperatures can damage them (45-degree C, or 113-degree F).

My cameras, metal detectors, portable power tools, and so on have lithium batteries. All fully-charged batteries lose energy when the tools, cameras, and so on are not being used. I top-charge my metal detectors and tools that are in storage every two months.

 

[Rafterman]

Leaving lithium ion batteries in your car is a bad idea. It gets way too hot, even in the glove box, for anything like that to exist.

I've been using these flashlights for years now: https://www.amazon.com/Anker-Tactic...er+flashlight&qid=1557008300&s=gateway&sr=8-3

Even on the lowest brightness it is brighter than my 4D Maglite.

Last time I needed a flashlight when I was in a situation like a flat tire = my cellphone's flashlight did the job very well.

But isn't the battery in that flashlight a lithium ion battery?

 

[BigMcGuire]

But isn't the battery in that flashlight a lithium ion battery?

Yeah I wouldn’t recommend leaving it in a car. Cellphones flashlights work really well. I have not had a flashlight in my car since 02 or so.

 

[myscrnnm]

All good, but while lithium batteries pack more energy than alkaline batteries they are more expensive. To me it makes no economic sense to buy a rechargeable lithium battery flashlight to keep in in the trunk of my car. I would still have to partially charge the batteries perhaps once per month (maybe every two months) to account for the natural discharge rate of the battery. But regular alkaline batteries are relatively cheap and aren't affected by the high temperatures as much as lithium batteries if left in the car's trunk during a hot summer. Lithium batteries don't take high temperatures well, so 113-degree temperatures can damage them (45-degree C, or 113-degree F).

My cameras, metal detectors, portable power tools, and so on have lithium batteries. All fully-charged batteries lose energy when the tools, cameras, and so on are not being used. I top-charge my metal detectors and tools that are in storage every two months.

These flashlights don’t use rechargeable lithium batteries. They use primary cell lithium 123As. They have higher energy density than both alkaline and lithium-ion batteries, and have a guaranteed shelf life of ten years. A lot of the myths surrounding lithium batteries stem from people not making the distinction between lithium and lithium-ion batteries, which operate differently. They’re only the same in that both contain the element lithium, but in different quantities.

 

[millerj123]

There is no need to buy tactical flashlights unless one is involved on police or military tactical operations, or because money to buy expensive flashlights like that is not an issue. Lithium batteries are used in cameras, laptops, phones, and a myriad of electronic devices that rely on batteries that are rechargeable and take longer to discharge (pack more capacity). These lithium batteries are different than the ones used in automobiles. To the OP of this thread: would you leave your laptop, or your camera in the trunk of your car during a hot day in Texas? While EV's have battery temperature management systems, cellphones, cameras, iPads, and so on don't. Laptops have cooling fans that energize as needed when you are using it, but not when stored somewhere.

My wife and I have 20 or more flashlights, including headlamps, and perhaps two or more tactical flashlights, none of which use rechargeable batteries. The batteries we use are Alkaline AAA and AA cells, 123, C cells, and D. These batteries are relatively inexpensive and last a long time. The headlamps use AAA batteries, and so several flashlights that cost under $15.00, including the Chinese made LUX-PRO LP600 and LP-400 (look at Amazon). While I still have some expensive flashlights that use 123 battery cells, we not longer used them because these alkaline cells were very expensive when we bought the flashlights.

Coast makes a good flashlight as you can see below (look at the specifications). It costs about $29.00 at Amazon. It is one of my favorite flashlights because it can be adjusted to project a bean or floodlight, and uses 4 AA battery cells.

COAST POLYSTEEL 600 1000 Lumen LED Flashlight with Pure Beam Twist Focus, Stainless-Steel Core, Crushproof, Black

Tackle tough work with tough-as-nails lighting. Delivering full size power from a full-size, 8-inch body, the PS600 flashlight matches lighting performance with the legendary strength of COAST POLYSTEEL design. With a run time of up to 40 hours on low, this three-mode workhorse maxes out at 1000 ...

www.amazon.com

You will notice that most flashlight brands include some "tactical" models that cost around $30.00, but what you want to do is to choose flashlights by "lumens (400 and 600 Lumens are fine, but 700 or more are very bright)," LED lamps, and battery cell type. I don't spend my money on rechargeable cells for flashlights, and this includes lithium batteries. Lithium may take longer to discharge which is a good thing if used in portable power tools (drills, drivers, and so on), but the flashlight Alkaline batteries are cheap and last long enough.

By the way, I live in the interior of Alaska where by December 22nd (or so) we only have about one hour of daylight, thus the number of flashlights I mentioned above.

Sadly, TexasToast has not been seen in nearly a year…. I had been storing jumpstart kits in my car, but one cooked in the trunk so back to jumper cables and no batteries in the trunk.

 

[AlaskaMoose]

These flashlights don’t use rechargeable lithium batteries. They use primary cell lithium 123As. They have higher energy density than both alkaline and lithium-ion batteries, and have a guaranteed shelf life of ten years. A lot of the myths surrounding lithium batteries stem from people not making the distinction between lithium and lithium-ion batteries, which operate differently. They’re only the same in that both contain the element lithium, but in different quantities.

Lithium does not react well to high temperatures. Battery failures such a short circuit can cause the battery, regardless of kind, to get extremely hot and burn or even explode. The greater the amount of energy in a battery, the greater the risk. Lithium batteries for flashlights pack a lot more energy than alkaline batteries, but alkaline batteries can tolerate higher temperatures:

I won't tell anybody what battery he or she should buy, however. But I would not store my cameras, metal detectors, my flashlight with lithium batteries, nor my laptop, in the trunk of my car if I were living in a place where the ambient temperatures are extremely high. The same for my high energy jump starter because it has a powerful lithium battery.
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Edit today Sept. 25, 2022
Powerful LEDs produce high temperatures. In fact, even the 400-600 lumen flashlights get hot if kept energized on HI beam for several minutes. The high heat seems to emanate from the LED, and some of this heat spreads back through the battery compartment. I have been surprised a couple of times after putting the metallic flashlights in my pocket and noticing how hot they feel. That said, it is up to the user to purchase whichever flashlight he or she wants.

Numerous articles about LED flashlights have been published, and some include the measures one should take to avoid overheating them. Warm to the touch could be OK since all LEDs get hot depending on the length of time the flashlight is used, but if it's too hot to the touch should serve as a warning that something is wrong with it.