Hello. I’m new here. I just purchased an Astrolux® FT03 XHP50.2 4300lm 735m NarsilM v1.3 USB-C. In the description it says that a 21700 battery will work in it. So I bought this battery… Nitecore NL2150R 5000mAh USB-C Rechargeable 21700 Battery. The battery is a little too long so I can’t close the flashlight. I’ve never bought this type of flashlight before. Am I missing something??
Yes. The Nitecore NL2150R is not only a protected 21700, but one with USB charging, which means it is extra long and won’t fit.
Hi. I’m not sure what’s meant by “my very own”. Do you have any suggestions for a battery that has proven to be a great battery for my model of astrolux?
The FT03 is a 26650 flashlight, so you might prefer a 26650 battery.
Since your FT03 supports both 26650 and 21700, then if you can afford it, here is the absolute best 26650 you can get today:
Thanks for stopping by, Ironcloud65!
Yeah, that cell’s a monster. Good cell, but loooooooooong.
Had to goggle it, over 77mm long, when a 21700 is by definition 21mm diameter and 70mm long.
Where’d you get it? Maybe they can exchange it without too much penalty. Not sure what lights would take a long cell like that.
Good unprotected 21700 cells aren't that expensive if you know where to look, but you might as well get a 26650 for maximum runtime.
Any suggestions on a reliable, and good quality battery?
Did you read post #5?
I bought it from Nitecorestore. I’ve asked them if they have a battery that would work but they haven’t responded.
Any unprotected 21700 or 26650 would be short enough.
A protected 26650 cells might fit, depending on how long it is.
If you want a 21700 cell, I can recommend some, but I honestly don't know which 26650 cells are good.
For single cell flashlights, you might as well get unprotected cells.
The protection is mostly for multi-cell flashlights, which can be a bit dangerous if you're not careful.
I’m not familiar with these batteries at all. Can you tell me what the difference is between a protected and unprotected battery is?
"protected:
When a circuit board is included in a Li-Ion battery that prevents cell damage caused by excessive discharge or current. Some flashlights sense low cell voltage and turn off, thereby providing protection as well."
https://flashlightwiki.com/Terminology#P
Protected cells are longer than unprotected cells.
I guess I need to find out what length of battery is suitable for my flashlight.
Is there any reason you need protected cells?
People typically get them for flashlights that take more than one cell, and even then sometimes people use unprotected cells.
Nice!
Only a handful of reputable manufacturers actually, physically manufacture lithium-ion batteries: Panasonic (Japan), Samsung (Korea), LG (Korea), Molicel (Taiwan). [Tesla (USA) manufactures lithium-ion cells as well, but only for their own use.] There are also countless Chinese manufactures, whom I personally would not trust at all.
For lack of a better term, let’s call these “base” cells. They are the original, unmodified battery cells coming out of a factory.
Base cells do not include any protection circuits or USB-C charging. They have flat tops, not button tops.
All of the common retail brands like Vapcell, Nitecore, Fenix, Thrunite, KeepPower, etc are just wrappers around one of these cells.
Some of these retail cells are “unprotected”, which means all they’ve done is put a plastic wrapper with the brand name around the base cell.
Some of them are “protected”, meaning there is a little PCB attached to the top of the base cell to protect against over- or under-voltage, and/or excessive current, and/or excessive temperature. The PCB usually has a thin wire running to the bottom of the cell so the protection circuit can measure the voltage. This wire is hidden by the wrapper, but you can usually feel it if you try.
Some of these protection PCBs now include a USB-C plug as well, to enable changing the battery directly via USB. So far, none of these are “really” USB-C, in the sense that they don’t support the USB Power Delivery protocol. In fact most of them won’t charge at all with a C-to-C cable, and instead require an A-to-C cable that always supplies 5V and at most 2A.
Protected cells are almost always button top, but there might be a few exceptions.
Protected cells are always a few mm longer, due to the thickness of the PCB and button top.
USB-C chargeable cells are a few mm longer still, due to the thickness of the UCB-C plug.
My personal preference is to buy only unprotected cells, and use them only in quality flashlights, which should provide all the protection you need.
There are two exceptions: “direct-drive” flashlights, which have minimal circuitry, and multi-cell lights. Direct-drive is kind of a niche thing: you’ll only find these from boutique sellers in the flashaholic community. Multi-cell lights require extra care because the cells can get out of balance. For these I would recommend either using protected cells, or just not buying multi-cell lights at all unless you’re going to be diligent about always starting with all-new cells from the same lot, charging all cells at the same time on a quality multi-bay charger, making sure that they all have similar starting voltages and take roughly the same amount of charge (i.e. they’re aging similarly), and never mixing cells. This is really whole topic unto itself.
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As you have enthusiast grade flashlight, and will probably be using more, then purchase a dedicated li-ion charger (I use the Vapcell S4 Plus) and use unprotected li-ion batteries which will fit in such lights.