Batteries - what you need to know

[David]

There are all sizes and types of batteries. Some are better than others and some are downright dangerous. The following is a discussion on this topic and others are invited and encouraged to chime in with their knowledge and experience.

First off, defining some of the types and this is not an exhaustive list but only a start.

Primary batteries.

These would be your disposable use-them-once-then-throw-them-away type of batteries. Duracell, Engergizer, Rayovac etc. They include alkaline, heavy duty and the like. Six years ago I did a test that I'll include here for an example and reference. Mainly D, C, AA, AAA but include other types like the button, watch and other styles of battery.

http://budgetlightforum.com/node/36316

Snipits of the test:

The last couple of years or so I’ve been increasing my supply of batteries, both rechargeable and consumable. Always looking for a bargain (while keeping value). I did the following test for grins and to see personally what would happen. I used two Maglite AA mini-mag with incandescent bulb to test them in. Here’s what I got:

Sunbeam Heavy Duty (Dollar Store non-alkaline) Continuous run time: 2:10 (dim at 1:30) 15 cents per battery normal price ($3 for 20)

CVS Brand Alkaline
Continuous run time: 4:58 (dim at 4:20) 49 cents per battery normal price ($11.79 for 24). BOGO brings it down to 25 cents per battery.

Harbor Freight & Tools Thunderbolt Alkaline
Continuous run time: 5:00 (dim at 4:50) 25 cents per battery normal price ($5.99 for 24). Sale price for this test ($4.29) brings it to 18 cents per battery.

Duracell Alkaline
Continuous run time: 5:20 (dim at 4:50). 42 cents per battery based on Walmart price of $9.97 per 24.

I’ll normally get the CVS alkaline batteries when they’re BOGO. But lately I’ve also been getting the HFT Thunderbolt batteries when they go on sale or I have the 20% coupon (which I always have a plethora). I was at Lowes yesterday and saw their Utilitech batteries. Never used them so I bought a 48 count box (and the box was a nice plastic carrying case) for $13.17. That’s 27 cents per battery so it’s about the same as the CVS brand and cheaper than Duracell. Only the Thunderbolt does a bit better and they came in second of the three alkaline brands I tested.

Sunbeam Alkaline (25 cents per battery)

Continuous run time 4:54 (dim at 3:24)

Fairly impressed with this battery for the price. Not quite as good as the Thunderbolt or CVS but not that far off.

So far the ranking based on run times stacks up like this:

1. Duracell Alkaline – Continuous run time 5:20 (dim 4:50) (cost for test 42 cents per battery)
2. Harbor Freight & Tools Thunderbolt Alkaline – Continuous run time 5:00 (dim at 4:50) (18 cents per battery)
3. CVS Brand Alkaline – Continuous run time 4:58 (dim at 4:20) (25 cents per battery if BOGO)
4. Sunbeam Alkaline – Continuous run time 4:54 (dim at 3:24) (25 cents per battery)
5. Utilitech Alkaline (Lowes store brand) – Continuous run time 3:51 (dim at 3:30) (27 cents per battery at normal store price.)

Rechargeable batteries:

These are batteries that you can recharge over and over again. In the long run they are more practical and cost efficient. It pays to get the best over junk.

In my experience, the two best I've used are Eneloop and Engergizer as far as AA and AAA batteries. Eneloop can be found in nice packages at places like Costco that often come with a charger. And of course Amazon and other retailers have them. These are probably the best overall from my research and can be recharged like 2100 times (depending on the battery), have a good amount of MaH (capacity of energy) and are advertised to retain 70% of their power level after 10-years of non-use.

I use Energizer in my Taser at work. They are rated for 100 5-second cycles and the power levels seem to last a LONG time. I normally only charge my taser a couple of times a year. And I routinely (as required by policy) to a 5-second cycle test at the beginning of each of my shifts.

Lithium Ion:

Lithium ion batteries have designations like 14500, 18650, 18350, 26650 etc. Many of these designations correspond to a particular battery type. For example;

10440 = AAA
14500 = AA
18650 = 2xCR123

Warning!

While a 14500 battery is physically the same size as a AA battery, it can't always be put in a device that uses a AA battery. The device, such as a flashlight has to be rated for lithium ion battery usage. The reason is that a AA battery is 1.5 volt while a 14500 battery is 3.7 volts. So if the device is not rated for lithium ion battery usage your going to damage it. And possibly cause injury to the user.

On the other hand, many devices like flashlights are often rated for both. For example, the little Sipik or SK68 flashlight that you can get on Ebay or Amazon by the gazillions is rated for both AA and 14500. As a ballpark, if the Sipik is using a AA battery it will provide around 80 lumens which is quite good for such a small LED flashlight. However, if you put in a 14500 battery you'll likely crank up the lumens to 300 which is substantially brighter.

Second Warning!

While you can skimp on regular batteries i.e get the cheap dollar store D, C, AA and AAA and only sacrifice run time i.e. your flashlight or other device won't run as long...DO NOT SKIMP on lithium ion batteries...EVER. The reason is one of safety. Garbage lithium ion batteries can 'explode' during recharging or if improperly recharged. I don't necessarily mean explode like a grenade, but they can 'pop' violently and discharge gases and liquid that are acidic.

The action starts at around the 3:00 mark.



A LOT of lithium ion batteries are made in China. Not necessarily a bad thing, however, China brands are notorious for two things i.e. mAh and lumens. Often called Chinese-mAh and Chinese-lumens. For example, a GOOD 14500 battery will typically have a capacity of around 750 mAh. A few perhaps as high as 900 maybe. If you look on Ebay you'll see crap like 14500 batteries listed as holding 1800 mAh for a buck each. Sounds great! After all it is more than double the GOOD brands and a LOT cheaper! Problem is that you can't fit that level of capacity in a 14500 and in all likely hood it's safe to take off the last zero for a more accurate capacity of 180 mAh. Worse yet, a good li-ion battery should get around 500 recharges, these will likely be around 5 and are unsafe as well like in the video I posted above. So stay away from blue label 'Surefire' brands and anything that has an exaggerated mAh capacity listed. That's to entice the suckers.

You need to go with a trusted label from a trusted supplier. The one I personally use is Mountain Electronics run by a man named Richard who is a member of Budget Light Forum and has an excellent reputation.

https://www.mtnelectronics.com/

This is the source I get all of my li-ion batteries from and I haven't been disappointed yet.

More to follow and others can detail their thoughts and experience as well.

[bdc]

I fully agree on the batteries. I have my supply of rechargeables. I use a reliable guy in Texas.

[ratf51]

I just got a light that uses an 18650 battery. How long will those batteries hold a charge if not used? What would be an average life expectancy for the battery before it would need to be replaced?

[David]

I just got a light that uses an 18650 battery. How long will those batteries hold a charge if not used? What would be an average life expectancy for the battery before it would need to be replaced?

If it's a good quality 18650 (such as Panasonic, Sanyo, Sony, Keeppower and others of that type) you should be able to get up to 500 recharges on it. If charged and left alone I've been able to use them up to a year later and still had a lot of juice left in them. Typical mAh for a good 18650 battery is between 2400-3600 mAh maybe 3800 nowadays.

In a flashlight that has a lot of lumen output you'll probably get a couple of hours on the highest setting. On the lowest, like moon mode you'll get days of continuous use.

Some 18650 tube lights also have a conversion tube to shorten it for use with 18350 batteries. Not as much capacity but allows for a smaller/shorter light with the same output.

[ratf51]

Thanks! So, here's my followup question: do these batteries work best for recharging and longevity when fully depleted then fully recharged or does it matter?

[David]

That should not be fully depleted. A good lithium ion charger like a Nitecore charger will be a smart charger and correctly and safely charge the batteries.

[bdc]

How long will those batteries hold a charge if not used? What would be an average life expectancy for the battery before it would need to be replaced?

The question was about 18650 batteries.

There is no "one answer".
1. You will read literature about a totally unused ever 18650 battery retaining a percentage of its original charge. Say, 70% for some years.
However, the batteries are not always delivered, "fully charged" and you may be informed to charge it before the first usage.
2. some flashlights take button top and others take flat head batteries. Then again, your flashlight may take both - so you should make a note and keep it with the flashlight.
3. some flashlights will "overheat" although designed to take an 18650 battery. You have to find out on your own.
4. My girlfriend and I access one or two inexpensive sipik sk98 flashlights for the 15-20 minutes nightly dog walk. I just recharged one, without letting go dead, after a couple of months of walking. I would be ecstatic if the 18650 battery took 500 recharges.
5. Your 18650 battery will have a rating (good luck if the manufacturer is honest in stating the rating and has good quality controls and that you have not purchased a fake name brand battery). Make sure that it has the rating required by your flashlight. Moreover, purchasing a higher rated battery that your flashlight requires is not necessary. It is just as wasteful as putting premium gas into a car designed for regular gasoline.

[David]

2. some flashlights take button top and others take flat head batteries. Then again, your flashlight may take both - so you should make a note and keep it with the flashlight.

Some tin foil will help make a connection in many flashlights if the battery is a tad too short to make a proper connection. Not ideal of course, but it can provide a quick fix.

3. some flashlights will "overheat" although designed to take an 18650 battery. You have to find out on your own.

Many of the more expensive lights will have a step-down feature so that if you are on the highest/turbo charge it will automatically step down in brightness after X amount of minutes to preserve battery life as well as allow the light to cool down a bit. Some of these high lumen lights will get quite warm on the highest setting. However, the highest setting is usually not the one that is used the most often. You just don't normally need 900+ lumens an extended duration of time. High lumens are good to have when needed i.e. self defense and shining 500+ lumens in the eyes of an attacker or lighting up the area around your car as you approach. But even just walking the dog 50-300 lumens is often more than enough for the task. And quite often you'll see flashoholics (use folks that REALLY like our lights like me and Bmyers) will look for a light that has a really low/moon light setting as it is very useful in many situations.

[ratf51]

The light I have is a Rofis R3. The light came with a battery, so I have no immediate worries re: its being the right battery, and the specs say I can use 2 CR123s in its place. The light has a moon setting that is probably about .5 lumens, low is at 20 lumens-- enough to move around the house if the power goes out. It has a medium setting that is 230 lumens, high setting of 560 lumens, and a turbo setting of 1250 lumens. So, next question, since the 18650 is equivalent to 2 CR123s, is it safe to put an 18650 in a light that uses 2 CR123s-- in other words are they fully interchangeable? My apologies if my questions seem elementary but right now I am something of a tabula rasa in regards to this topic. My gut says that they ought to be interchangeable but then that could simply be the hotdogs I had for lunch.
(I checked the flashlight specs and updated.)

[David]

Ask as many questions as you like. That's what I did and had folks nice enough to answer them

A typical 18650 ranges from 3.7 to 4.2V whereas 2xCR123's would have 6V. So it depends on the driver (circuit board in the flashlight) as to whether it can handle the increased volts without damage. If it's safe to use one or the other the specs/instructions should state it. If not, I'd be a little leary. I've used a 10440 battery in a light that was 'suppose' to be rated for it and AAA batteries. Apparently it was only rated for AAA so the 10440 fried the driver. Didn't blow up or anything but basically it broke the light.