Looking for a rechargeable battery for my flashlight

[Tnq]

Hello,

I'm about to get Fenix PD35 Tac Edition flashlight, and i would like to get a rechargeable battery for it. After browsing this forum, i see a lot of people recommending Panasonic NCR18650B as the best choice, but what caught my attention is that they work best as a pair and not so much as a single battery, which is what i need. Since i'm not very knowledgeable about flashlights in general, i would like to ask for your help in determining whether these two are compatible, how good they would work together and, as this battery has a button top, would it fit inside Fenix PD35 Tac Edition flashlight ?

Since i'm going to need a charger as well, and my only two options are Fenix ARE-A2 and Nitecore NEW i2, can you tell me which one would you choose and why ? Also, i have found an information from a user somewhere else that Nitecore NEW i4 charge must charge at least two batteries at once (this refers to 10440 battery specifically in the comment) or else "[FONT=&quot]overheating or explosion may occur" if there's only one battery charging, can anyone confirm this to be true in general or does that apply only to 10440 batteries ? This particular Fenix charger is supposed to [/FONT][FONT=&quot]automatically set the correct charge rate but a person who owns it claims how "[/FONT][FONT=&quot]If you put ANY Li-Ion battery in it, it will charge it at 1000 milliamps[/FONT][FONT=&quot]. That is DOUBLE the safe charge rate for ALL Li-Ion batteries smaller than an 18650 battery." As this doesn't apply for the type of battery i need, it won't be a deal breaker for me, but i would like to know if this is true in case i need it in the future.

I would like to thank everyone for their help in advance and wish you all a great day,
David[/FONT]

 

[RetroTechie]

Welcome here David! :wave:

Looking at the PD35 specs, it seems you need a button top 18650. Most 'naked' 18650s are flat-top, so that narrows your selection quite a bit. Note that some button top versions may be cells where button top was added by a 3rd party (and perhaps re-wrapped). So there are some button top cells that original manufacturer never sold with button top. For example I don't think (but might be wrong) Panasonic ever made NCR18650B with button top.

For maximum runtime at Turbo setting you'd look for an 18650 that has the highest capacity when discharged at roughly 3A (which is modest load for most 18650s). Highest capacity cells in this size come from just a few manufacturers, most notably: Sanyo/Panasonic (that is 1 ), LG, Samsung or Sony. The best ones currently hover around 3500 mAh. I'd consider anything 3000+ mAh an excellent choice.

A great place to compare actual capacity of 18650's when discharged at various currents, can be found here: 18650 battery comparator
(by our great friend HKJ)

There are maaannyy choices these days that would suit this light fine. Some 'random', excellent choices that I have seen for sale in button top style:
LG 18650 MJ1
Sanyo/Panasonic NCR18650GA
Samsung INR18650-30Q

Most button top 18650's you'll find are "protected" cells, that is: with an electronic circuit added to protect against overcharge, overdischarge, short circuit etc. My humble opinion: with a quality single-cell light (like this Fenix), and a decent charger (not a $2 eBay one), protection pcb has little added value if any. But it does increase price, length, self-discharge, and adds a potential failure mode. In other words: 'unprotected' is fine for this application.

Many button top 18650's will be re-wrapped by 3rd party. If that 3rd party is respected flashlight (or charger) vendor like Fenix, Nitecore, EagleTac, Olight, Xtar etc, chances are quality cells were used and you really can't go wrong. But you may pay a lot for the pcb + brand name.

Just avoid vendors that you've never heard of, have a bad reputation, <SOMETHING>Fire cells from eBay, AliExpress etc. Or 18650 cells that are advertised as >3600 mAh. There's a lot of junk & even fake stuff out there... :sigh:

Other than that it's just a matter of where you're ordering from, shipping costs, in stock or not, and how much you want to spend to get a few minutes extra runtime in the highest-power mode(s). For daily use 2600 or 3000 mAh doesn't really make a noticeable difference. And in "eco" mode, you won't care whether it's 2 weeks, or 3 weeks runtime. :laughing: If there's any specific (online) store(s) you'd prefer to order from, let us know & we can help you pick from their offerings.

but a person who owns it claims how "If you put ANY Li-Ion battery in it, it will charge it at 1000 milliamps. That is DOUBLE the safe charge rate for ALL Li-Ion batteries smaller than an 18650 battery."

Just read the manual for a charger you're considering. And/or check reviews (like on HKJ's site above). Yes 1A is a highish charge rate for smaller cells like 14500 or 16340. But even in small sizes there are cells (that don't handle high currents well), and there are cells (that do). For example an 18350 I have here is actually rated for 1A charge (and 10A discharge ). A charger I have distributes its charge current over 2 slots, so on that charger I can cut charge current in half by having a 2nd cell charging in the other slot. Etc etc. No hard rules there other than:

• Better not exceed specs, and
• Higher charge / discharge rates cause cells to wear out faster.