Hi all… Im a newbie in flashlights… Need help to understand more abt the batteries. There are so many types of batteries in the market for 18650. Is it true the bigger mAh… The longer it can last or higher charge capacity… But i understand for a xm-L led max output is 3000mA. Can i use a 4800mAH 3.7v battery?? Will it burn out the bulb?
First of all: Welcome to BLF! You'll love being here! :)
You are mixing different things here:
- mAh means battery capacity
- mA means (emitter or tailcap) current
=> capacity / current = (approximate) runtime (larger capacity or lower current leads to longed runtime)
=> There's no problem in using larger capacity cells even if the emitter current would be only 350mA
...but: There's no such thing as 4800mAh 18650 cell. If you see one, it is fake and possibly very bad quality => Don't even think buying or using one. Buy good quality cells like Panasonic protected 3100mAh and be happy.
Ps. XM-L max output is not at 3A
I agree, don’t buy cheap batteries. Stick with known quality ones.
If you are new to all of this, then make sure you use protected batteries and make sure you get a decent charger too.
Also it’s not all about mAh. Sure the higher the capacity the better, but unless you are relying on a flashlight for work or something life threatening, then most people won’t actually tell the difference between a 2900mAh and a 3400mAh battery. The only down side is you’ll have to charge the 2900 one sooner, but you’d probably not notice it in actual use.
Fasttech.com sell some good priced protected Panasonic batteries. Check them out.
The Sanyo 2600mAh is also a very good battery too. Lower capacity than the Panasonics, but they generally hold their voltage more stable, this means they can sometimes offer just as good, or longer runtime under high loads as the high capacity Panasonics do.
Thanks guys… now at least i can start to learn abit more… Then how can i know from the battery itself the current its emitting… Only mAH n voltage is printed…
How much current the battery is supplying is determined by the driver and the LED.
For example, a moonlight mode would draw less from a cell than the brightest mode.
You can use a digital multi-meter to measure the current that the battery is providing by probing the battery and the flashlight body.
In addition to the factors to consider that others mentioned, find out the battery max ‘length’ your flashlight can use. For example, the ‘65’ in 18650 is the standard length in mm. The length of unprotected 18650 is 65mm, but protected ones can be close to 70mm. Higher capacity protected Panasonics are well known to be longish and your flashlight may not fit them. Look up the length in the spec of the battery when you buy.
Another factor you should look for is whether your flashlight can accommodate ‘flat’ top, in contrast to ‘button’ top. If your flashlight’s contact for + does not have a spring, you cannot use ‘flat’ top 18650. Look at the pics of the battery for flat or button top.
tests of individual (different brand & capacity) 18650s:
18650 tests
and the tests of individual batteries (same website, different page)
and here’s a great website to teach you all about batteries (it’s maintained by a manufacturer of industrial battery chargers):
enjoy! and welcome!
The first 2 links don't seem to work.
I suggest going to wiki and reading about voltage, current, and resistance