Buying rechargeable batteries.

[nettle]

New rookie here. I have Fenix flashlights, charger, and batteries. Not saying they are the best but they are working out for me so far. I am going to buy rechargeable batteries for all our other battery powered stuff (AA, AAA, Fenix 21700, Fenix 18650) . The only rechargeable batteries I have tried so far are the Fenix. Maybe Eneloops are better?

 

[ChrisGarrett]

Eneloops (made by Fujitsu) are the best NiMH rechargeable batteries made for the consumers of Planet Earth.

Chris

 

[NiOOH]

As said, Eneloops are the best for AA/AAA. I recommend the white ones (i.e. not Eneloop Pro).
In order to get the maximum out of them in terms of performance and service life, you'll need a decent charger. For the LiIon cells, do you need protected?

 

[nettle]

I'm not sure what "need protected?" means.

 

[dc38]

I'm not sure what "need protected?" means.

Integrated protection circuit, helps to prevent overcharge/discharge.

 

[nettle]

The charger is due to be delivered Monday. I just went online and checked the specs and it appears to be protected. It's a Fenix ARE-D2. Thank you for the heads up!

 

[aznsx]

The charger is due to be delivered Monday. I just went online and checked the specs and it appears to be protected. It's a Fenix ARE-D2. Thank you for the heads up!

In this case, I believe 'protected' refers to the lithium-ion cells, not the charger. In the case of Fenix lights using lithium-ion cells, I recommend using the Fenix-recommended type (which I'm fairly certain is 'protected' cells), although not necessarily their specific brand (although I've personally used many of their cells with good results and they've done well (18650 & 16340)). I also use protected cells from other manufacturers in their lights. Keep in mind that per ANSI FL1 standard, their published flashlight specifications are based on use of a specific type of cell (the one supplied with &/or recommended for it), and that should be stated together with those specifications.

If anyone doesn't fully understand the reasons for using 'protected' cells, I particularly recommend their use to those people, because the decision to do otherwise should absolutely be based on full knowledge of the subject.

For NiMH, Eneloops are by far the most recommended brand, although I use far fewer NiMH compared w/ lithium-ion, so I can't really speak to those. They work for me, but I've never bothered with the alternatives. Their reputation speaks for itself in this case.

 

[Chauncey Gardener]

In this case, I believe 'protected' refers to the lithium-ion cells, not the charger. In the case of Fenix lights using lithium-ion cells, I recommend using the Fenix-recommended type (which I'm fairly certain is 'protected' cells),

If anyone doesn't fully understand the reasons for using 'protected' cells, I particularly recommend their use to those people, because the decision to do otherwise should absolutely be based on full knowledge of the subject.

^ This!

 

[nettle]

Again, I am new here and advice like this helps me learn and is much appreciated. I have two different Fenix flashlights using 21700 and 18650 batteries respectively. All the batteries for my Fenix flashlights are Fenix brand. The Eneloop's are for other stuff like TV remotes and other battery powered things that use AA/AAA batteries.

 

[NiOOH]

It would help if you give the model of the lights and cells used. My Fenix lights use only protected cells, but they are over 10 years old. Don't know if their newer stuff uses protected or bare cells.

 

[PaladinNO]

Greetings!

For AAA / AA, I buy Eneloops for everything without question. I've tried Energizer, Duracell, GP Power and they all turned out to be a waste of money - i.e. they didn't last very long..

White Black Eneloops for older, less powerful lights (under 250 Lumen or so) and other low-power devices, and the black white Eneloop Pro batteries for modern lights.

For 18650, I like Nitecore (NL1835HP / 36HP for the most powerful lights) and Keeppower cells. Limited choice and availability is a problem for me, but those works for me. I don't own any of the current Fenix 18650 cells, but I am certain those work fine too. Their current 21700 cells, of which I have many, works great.

For off the shelf lights, protected cells are technically redundant, but recommended for safety and just peace of mind. Brand name flashlights also have protection curcuits built-in for extra safety. Protected cells have over- and under-current protection, as well as over- and under-discharge protection and short-circuit protection. They are basically fool-proof, and their only limitation lies in the limited power delivery, which is typically 3-4 Amps, and up to 8-10 Amps maximum.

An unprotected battery can deliver more power / Amps (from 20 and up to around 50 A), and needs to be both handled and used with a bit more care. But they are practically no less safe than protected cells so long as you use common sense. Just don't place unprotected cells in series (stacked / on top of each other) in a light - that's arguably a recipy for a bomb. But unprotected cells in parallell (next to each other) is fine. Protected cells can handle both configurations just fine.

I wrote a novel on battery protections here:

Post in thread 'What happens if you use protected cells in a light that only uses unprotected cells.'

Jan 12, 2025

Take this with a grain of salt, as this is my understanding of it all and parts could be wrong.
Exactly what happens if any of the protections kick in, I actually don't know.

As far as I know, there are 5 types of protection for batteries:
Over-current
Over-voltage
Under-voltage
Short-circuit
Overheating

Some of these safeties are beneficial during use, and some during charging.

TL;DR:
Buy quality flashlights, batteries and chargers, and don't cheap out on either of the things. Use common sense at all times, be extra careful at first to gain personal experience with your devices and...

• PaladinNO

• 

Edited.

 

[NiOOH]

White Eneloops for older, less powerful lights (under 250 Lumen or so) and other low-power devices, and the black Eneloop Pro batteries for modern lights.

You should be doing it the other way around. White Eneloops, while having lower capacity, have lower internal resistance, and could sustain higher voltage under load. They are also a lot more robust than Eneloop Pro, with longer cycle life. Eneloop Pro may have some advantage initially, but after 40-50 cycles (especially at higher discharge currents) their IR start to rise sharply. White Eneloops maintain low IR for hundreds of cycles, providing they are charged correctly.

 

[PaladinNO]

You should be doing it the other way around.

Thank you, my knowledge of the Eneloops is clearly outdated.

I will admit I never looked that much into them, but given the "Pro" name and a description of use with high-draw devices (at least the way I understood it, back when I read about them), I have always taken it for granted than the Pros were intended for flashlights, and the regular whites for things like the kitchen timer and remotes.

But reading about them now, I apparently stand - sorry; sit - corrected.

 

[nettle]

It would help if you give the model of the lights and cells used. My Fenix lights use only protected cells, but they are over 10 years old. Don't know if their newer stuff uses protected or bare cells.

Fenix E30R= Fenix 18650 batteries
Fenix PD40R= Fenix 21700 batteries