A question:

When do you replace your flashlight-batteries? Do you do that when they are for example half-full, or every week, etc?

I usually replace mine when I notice the light getting dimmed out, at least with the incandescent ones. I can't remember when the last time was I replaced batteries in any of my LED lights. It seems by the time I need to replace batteries in them, I have either broken the flashlight or otherwise replaced or upgraded it, or else I just don't use it that much. Or...it is one of my wind-up flashlights which just keep going and going and going...

I find that I have spare batteries in virtually every location and kit, so I don't tend to replace the bat's in a flashlight until they seem dim, with one exception...

My EDC light is a single AAA light on my keychain. Right now it's a Fenix L0D, but, it was an ARC AAA for a while, probably a Mag solitaire before that. I replace that battery with a fresh one fairly often, probably monthly... because when all I have is my keychain, I don't have a spare battery, so I think it's worth doing pre-emptive battery changes.

Usually, the one I'm taking out is fairly fresh, so often use it for something less critical that uses AAA batteries, and put a fresh one in the EDC light.

On a related note, for my EDC light, I spend the extra money for the AAA Lithium batteries. Most everything else gets more conventional Duracells. Do you folks find that you use Lithiums for more things now that they are available readily in AA and AAA?

I usually check all of my flashlights at the beginning of each month.Since not all are used equally I find that some need to be changed more than others.This usually means that I catch any that may be dead before I need to use it.

My edc is run off of a stack of lithium disks running one led. I've been using it now for about 2 1/2 months and it seems to be doing fine. It cost me about $4, and when the batts go, I think it will be cheaper actually to replace the whole thing rather than chase down the batteries for it. I am always finding something else that catches my eye, so I guess I am too consumer oriented

I used to have a 4 AAA cell three led light as my edc. I think I replaced the batteries in it once in two years. I just don't use a flashlight that much.

Hi Be_Prepared

I just find Lithium batteries just to expensive for general use although they are excellent and very useful in AA and AAA and I will use them in flashlights which must work without fail when the flashlight is being stored for an emergency. They are really useful because of the shelf life i.e greater than 15 years.

I generally use a specific NiMh battery now called Eneloop made by Sanyo. Most NiMh batteries have a serious downside in that they self discharge usually discharging fully after 3-4 months. The Eneloop batteries will only discharge 15% within a year. As for determining the charge on the NiMh batteries the charger,a La Crosse Technology BC900, provides an indication of the voltage across the cell. The voltage normally ranges from 1.20V (empty) to 1.42V (full). The charger also allows the current to be selected for different charging times 200mA 500mA 750ma and 1000mA.


La Crosse BC900



Eneloop Cell.

For flashlights which I rarely use but are important to have ready, like the ones in my cars, I change the batteries twice a year, when we change the clocks for Daylight Savings Time. Those lights are loaded with alkaline AA's. The interior of a car is not a forgiving place to store anything, whether batteries or water or even a ballpoint pen, so I would rather be conservative about having "fresh" batteries in the light. I try to check that the light works by turning it on monthly, but I don't actually unscrew it to see if the battery is leaking. Leaking batteries is something most of us have probably experienced at some point, and they tend to ruin your lights, so that's another reason that I replace the batteries twice a year even if the batteries were hardly used.

I could use lithium AA's in those car lights and probably just let them sit longer without any checking, but I feel more confidence in the batteries if I change them more often, so I just use cheaper alkalines and change them twice a year. The old batteries then go into a radio and will eventually be used up, so it's not wasted.

For lights which I use more regularly, I use rechargeable batteries. The Sanyo Eneloops which bentirran mentioned are excellent for flashlights which take AA/AAA batteries. I hear that they will soon come out with C/D sizes, which will work for powering those common C/D-size Maglites for a good long time. NiMH rechargeables are becoming very useful alternatives to alkalines or lithiums, now that low self-discharge chemistries are becoming available.

I haven't looked into rechargable bat's for a few years, so it's interesting to hear your observations on them. It makes them worth reconsidering. I know that most of the devices that I have using rechargable's are now Lithium Ion, like my laptop, cell phone, and camcorder, and they are worlds ahead of what similar devices had 10 years ago. Remember the NiCad batteries that would suffer from memory if you didn't manage them well?

Annually... every six months for something I don't use much seems real wasteful.

NiCad suffers from "Memory Effect". I was shortening it to just memory as you did until someone once asked me why don't they just make them without a memory. So shortening the term can confuse those that don't understand the technology.

I've switched over to the Sanyo Eneloop recently after having given up on re-chargeables for a while. It seems in the race to get the most capacity the manufacturers forgot about reliability. The capacity of NiMH went up so high that they would discharge themselves faster then you could use them and Lithium Ion rarely last more than a 3-4 years and NiCad which I uses to be able to run for 10 years are almost impossible to find.

I've found that a good charger helps too as most of the ones you buy from the stores don't fully charge the batteries or get them too warm. I bought a $40 MAHA and after a few cycles some of my old 1600mAh NiMH's are now lasting through two weeks of use in a baby monitor where they would only last a couple days before after charging in charger I bought at WalMart.

So I've went to a charge after use or every 6 months now and most of my gear I have two sets of re-chargeables so I can be charging one set while using the other so there is zero wait time and I'm never without a piece of gear. I have almost 4 dozen Eneloop's now with a couple of the $9.99 30 packs of AA's that Home Depot sells and some Lithium AA's for backup. Then my MAHA charger is a 12v in so I can power for various sources if the grid were to be down.