Hi there i recently brought two torches and Fenix 3500 batteries. Until i joined this forum i didn’t know about IMR vs INR where a option. What i would like to know is one very more safer than the other the others, and are they all interchangeable in torches given they are the right size and top to them ?

ICR, IMR and IFR used to be meaningful, but they’ve kind of become somewhat obsolete. We still see IMR (Li-Manganese) and even IFR (LiFePO4), but ICR (Li-Cobalt) has slithered away, with the advent of hybrid chemistries, which encompass more than a few chemical combinations.

I prefer ‘high drain’ with ‘moderate drain’ when choosing a cell for a particular application.

It used to be (2012) that you could have 5A+ continuous current and lower capacity, or you could have <5A and higher capacity, but these new hybrid chemistries have turned that on its head.

Always match the cell to the load your device will require, so you need to know your ‘load’.



I = lithium

C = cobalt

M = manganese

N = nickel

F = iron

R = round/cylindrical

Found this thread that may be of help.

Lithium IMR vs ICR vs IFR

For the most part, yes they’re interchangeable. Lights that require high drain drain batteries will most likely need IMR batteries (since these are high drain) but a typical 1000 lumens 1x18650 light isn’t all that demanding and so any chemistry will be just fine.

Some complexities but a good place to start:
Types of lithium batteries

Also this guy from Electronic Cigarette Forums (ECF):

Goes by the name Mooch and here’s a link to his page:
List of battery tests

That last one is rather extensive but can be used for reference. Mind you he’s testing for high drain capabilities as their “mods” are for vaping.
Personally, stick with the known reputable brands as Samsung, Sony, and LG. However, many counterfeits of these - often on china sellers.

Edit: If you don’t care or want to track down a good seller, try a vape shop. They always have top quality cells but at a higher cost.
Depending on usage (cycle times) you’ll need a good charger:
Lygte Battery Chargers Review

first, regardless of chemistry, the protected ones are safer than the unprotected ones, Unless your lights have built in overdischarge protection. (this is uncommon, which is why it is prudent to use protected cells)

of the unprotected ones, IMR are safer than ICR, but until you learn about the risks of overdischarging, and develop fool proof strategies to prevent that from happening, you should imnsho only use protected cells in lights with no built in overdischarge protection.

Note that lights that indicate they use Low Voltage Protection, are not the same safety level as lights or batteries that have Overdischarge protection.

to learn more about LiIon safety start here
Lithium-ion battery safety 101

here is the CliffNotes version

IF your light gets left on by mistake and runs the battery down below 2.7 volts, there is a risk of Venting with Fire when recharging. So unless the light has built in overdischarge protection, or the battery has built in overdischarge protection, it is possible that a light can overdrain the battery. The danger occurs when you recharge an Overdischarged battery because it can overheat and start a fire. For this reason you should not charge LiIon batteries unattended, and it is poor safety practices to put a LiIon cell on a charger overnight. You might wake up to a fire.

Im sure many people here will find this post alarmist, and it IS supposed to be.
I suggest you start your foray into LiIon use with an Abundance of Caution.

And I think you have done so, by asking your question, and showing a desire to learn more about LiIon Safety. Well done!