Simple, "plug & play" 18650 batteries

Well, finally looking into getting some 18650 batteries. I still have quite a few CR123 batteries that I bought over 10 years ago when (I forgot what store) was getting rid of Duracell CR123 batteries. However, I do have a few flashlights that need fully charged lights to use the high setting which I usually prefer. So, instead of using CR123 for only an hour or so & throwing them away, I'd figure I'd look at rechargeables and use the CR123 as emergency back ups or for the 1 or 2 flashlights that have low voltage drop-ins (60WLLL).

I've read a bit here and there about charging/discharging, cycling, storage, etc..... Quite honestly, wasn't up my alley. Still isn't.

I am looking for opionions/input regarding the protected 18650 lights that charge via USB (i.e. from Fenix or Streamlight).

Just looking for something that I can plug into a USB cord, walk away, and eventually unplug it when its charged.
Question is, are those batteries really that easy to deal with?
Is there anything to worry about?
Is the performance any different from non-usb charging batteries?

Re: Simple, "plug & play" 18650 batteries

prof student said:

.... Just looking for something that I can plug into a USB cord, walk away, and eventually unplug it when its charged....

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My opinion, lithium ion battery chemistry is not good for this.

I am not really comfortable even with charging phones / tablets / laptops / etc / etc, unattended, and those have far more sophisticated monitoring and safety systems incorporated into their power packs.

There are other reasons I prefer to avoid the individual cells with built-in chargers, which includes adding more potential points of failure, adverse effects on size compatibility and robustness, increased risk of short circuiting, and others.

Re: Simple, "plug & play" 18650 batteries

I am in full agreement with archimedes. Though the industry seems to try to make these cells easier to use, the truth is obfuscated, and a false sense of security is likely.

Get educated. There's only a handful of things to be aware of:

• Don't let your LiCo cell go below 2.5V, protection circuit should kick in, but don't rely on it, and know the state of charge.
• Never recharge a LiCo cell without protection that drops below 2.5V
• Rest your cells 1 hour after use before charging, rest your cells 1 hour after charging before use.
• There are a few new great non-LiCo chemistries now that do not require protection circuits and can withstand going below 2.5V at the expense of capacity and cell life, INR and IMR, generally for high amps, but work fine with lower amps.

Unless I am forgetting something (help me CPF), that is the nutshell primer. How hard is that?


Get some decent cells and a half decent charger. Know that what you are working with is potentially very dangerous. Do not abuse your cells. And just enjoy your lights with guilt free lumens.

Re: Simple, "plug & play" 18650 batteries

chillinn said:

Get some decent cells and a half decent charger. Know that what you are working with is potentially very dangerous. Do not abuse your cells. And just enjoy your lights with guilt free lumens.

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Well, I was only looking to get 1 or 2 cells & I don't have much $$ right now.

What do you think of the ones from Fenix? Of course it's their own description, but they seem to be pretty well built & safe.

Re: Simple, "plug & play" 18650 batteries

Asked and answered. For about the same price as 2 of those rather expensive Fenix ARB-L18-2600U cells ($27.90), you can get two far superior conventional Li-ion cells with more capacity and a 2 slot Li-ion charger, ($28.95). Here is HKJ's review of the NiteCore UM20. Here is HKJ's review of the KeepPower IMR18650 3200mAh, though KeepPower changed the sticker labels since.