IMR 18650 vs Regular 18650

Marquis07

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Hey guys, I couldn't really find clear answers on the web, so I have some questions about 18650s.

1. What are the disadvantages/problems of using a regular 18650 to power a flashlight that requires an IMR 18650? Also, will it damage the battery over time?

2. Is there a rule of thumb in knowing if you need an IMR or regular? Say, if the flashlight is over a certain amount of lumens it needs IMR?

3. What are the pros/cons of using an IMR 18650 to power a light that takes a regular 18650?

Thanks in advance!
-Mark
 

Olumin

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Generally the manufacturer will note whether a IMR is required/recommended or not.
In short IMRs are unprotected cells & (usually) can deliver higher currents then protected ones. They are used in high-drain flashlights, often featuring high-lumen turbo modes.

Using an unprotected cell over a protected one carries the usual potential hazards, but in single cell devices there should be no problem as long as the cell is not over discharged. Most lights these days have in-build over discharge protection. If you arent sure its advisable to charge the cells sooner rather then later and (if you have it) periodically check their voltage with a multi meter). I usually charge at 3.4-3.5V, but never let a li-ion battery go below 3V, if it does I would advice against charging it as it can be a potential fire hazard. I would avoid using them in multi-cell lights, as it cannot be ensured that all cells discharge equally, due to slight differences in capacity & drain on the individual cell.
 

Marquis07

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Generally the manufacturer will note whether a IMR is required/recommended or not.
In short IMRs are unprotected cells & (usually) can deliver higher currents then protected ones. They are used in high-drain flashlights, often featuring high-lumen turbo modes.

Using an unprotected cell over a protected one carries the usual potential hazards, but in single cell devices there should be no problem as long as the cell is not over discharged. Most lights these days have in-build over discharge protection. If you arent sure its advisable to charge the cells sooner rather then later and (if you have it) periodically check their voltage with a multi meter). I usually charge at 3.4-3.5V, but never let a li-ion battery go below 3V, if it does I would advice against charging it as it can be a potential fire hazard. I would avoid using them in multi-cell lights, as it cannot be ensured that all cells discharge equally, due to slight differences in capacity & drain on the individual cell.
I have a Thrunite TC15 that came with 1 protected IMR 18650. Yes, it has a high lumen turbo mode. By default, they intend it to be powered by IMR, but they don't say if a regular can or can't be used if necessary.

I am wondering if I put a protected regular 18650 in it, will the battery be damaged over time by trying to supply more amps than it's supposed to?
Or would the light simply get the max amperage the battery can supply and function with less power?

I already tried asking Thrunite, and they weren't much help.

Thanks for the response.
-Mark
 

Olumin

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Li-ion and IMR have the same voltage, but IMRs have lower internal resistance that makes them more suitable for high-drain applications. Using a regular Li-ion cell in a device designed for high-drain cells can be dangerous as the cells could be damaged. I would advice against it. Use cells which are rated for the amperage that is required. All cells will be rated for a maximum continuous draw in A or mA, that rating should match or ideally exceed the devices requirements.

Using a high-drain cell in a low drain device on the other hand is safe, again, as long as the cells are not over-discharged. If the cell is protected thats of little concern, but most high drain cells are unprotected.
 

Marquis07

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Li-ion and IMR have the same voltage, but IMRs have lower internal resistance that makes them more suitable for high-drain applications. Using a regular Li-ion cell in a device designed for high-drain cells can be dangerous as the cells could be damaged. I would advice against it. Use cells which are rated for the amperage that is required. All cells will be rated for a maximum continuous draw in A or mA, that rating should match or ideally exceed the devices requirements.

Using a high-drain cell in a low drain device on the other hand is safe, again, as long as the cells are not over-discharged. If the cell is protected thats of little concern, but most high drain cells are unprotected.
Ah, that makes sense. Thanks for the help!
-Mark
 

Lynx_Arc

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I just looked up your light and it seems it does 2300 lumens and at let's say 150 lumens/watt and 3.6v that comes out to be over 4A and likely that number is higher as the efficiency of LEDs drops the higher the power supplied to them plus losses in circuitry and wiring etc occur.
I would say that to be safe you need at least a battery able to handle 10A continuous and there are some 18650s I believe that are rated below 5A like the Panasonic NCR18650B I think is rated about 4.8A max in the 3400mah capacity. Typically the higher drain batteries are more limited in overall capacity I don't think there is any 20A 3000mah 18650s used in tool batteries at all for that reason. I would recommend not using any battery rated below 10A output in that light if I did my math right there could be a lot of common 18650s that could barely handle the high mode and liklely give sub par performance while the battery struggles and gets hot and it could greatly reduce the lifespan of it.
 

Marquis07

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I just looked up your light and it seems it does 2300 lumens and at let's say 150 lumens/watt and 3.6v that comes out to be over 4A and likely that number is higher as the efficiency of LEDs drops the higher the power supplied to them plus losses in circuitry and wiring etc occur.
I would say that to be safe you need at least a battery able to handle 10A continuous and there are some 18650s I believe that are rated below 5A like the Panasonic NCR18650B I think is rated about 4.8A max in the 3400mah capacity. Typically the higher drain batteries are more limited in overall capacity I don't think there is any 20A 3000mah 18650s used in tool batteries at all for that reason. I would recommend not using any battery rated below 10A output in that light if I did my math right there could be a lot of common 18650s that could barely handle the high mode and liklely give sub par performance while the battery struggles and gets hot and it could greatly reduce the lifespan of it.
Thanks for the info! Long story short, I have a Thrunite battery charger/power bank that come with a regular 18650 ( 7A ) in it. I want to be able to use the battery in my TC15 as an emergency backup. I'll try measuring the amperage on the lower levels to see how many of them I can use that are under 5 amps. It's not a great solution, but it will mean that I can use my battery for more than the power bank.
Thanks again,
Mark
 

Lynx_Arc

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Thanks for the info! Long story short, I have a Thrunite battery charger/power bank that come with a regular 18650 ( 7A ) in it. I want to be able to use the battery in my TC15 as an emergency backup. I'll try measuring the amperage on the lower levels to see how many of them I can use that are under 5 amps. It's not a great solution, but it will mean that I can use my battery for more than the power bank.
Thanks again,
Mark
I personally would advise against using batteries that are rated under 10A in that light regardless of how much current it takes it likely is too close to 5A that it would be harmful to the battery if not worse. When it comes to batteries the higher currents from them used are potentially more dangerous when things go bad. One other thing is a battery that cannot hold the high current will be dimmer in use on the higher/est modes plus if the light circuitry drops down due to voltage drop you may find them not sustaining high output well.
 

Marquis07

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I personally would advise against using batteries that are rated under 10A in that light regardless of how much current it takes it likely is too close to 5A that it would be harmful to the battery if not worse. When it comes to batteries the higher currents from them used are potentially more dangerous when things go bad. One other thing is a battery that cannot hold the high current will be dimmer in use on the higher/est modes plus if the light circuitry drops down due to voltage drop you may find them not sustaining high output well.
Ok, I'll just get an IMR to use in the charger instead of the regular one. It's by far simpler and what you said makes sense.

Flashlights are my hobby, but I don't know much about batteries, so thanks for the help!

-Mark
 

Lynx_Arc

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Ok, I'll just get an IMR to use in the charger instead of the regular one. It's by far simpler and what you said makes sense.

Flashlights are my hobby, but I don't know much about batteries, so thanks for the help!

-Mark
I'm not the authority on batteries on the forum here others know a lot more about them but I feel it is better to be safe involving lithium batteries of any type than push them to their limits as they have such high energy density and potential that if unleashed can be dangerous, even deadly. Another thing is when you do get new lithium ion batteries one thing I always do is to monitor them the first time I charge them and be more careful the first time I use them in case I have a defective battery I don't walk off and have a serious problem. I even stuck around when I first charged my phone till it completed and when I drained it down to 30% I watched it recharge again to see if it did it properly.
I did similar with nimh and nicad batteries/chargers at the beginning.
 

Marquis07

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I'm not the authority on batteries on the forum here others know a lot more about them but I feel it is better to be safe involving lithium batteries of any type than push them to their limits as they have such high energy density and potential that if unleashed can be dangerous, even deadly. Another thing is when you do get new lithium ion batteries one thing I always do is to monitor them the first time I charge them and be more careful the first time I use them in case I have a defective battery I don't walk off and have a serious problem. I even stuck around when I first charged my phone till it completed and when I drained it down to 30% I watched it recharge again to see if it did it properly.
I did similar with nimh and nicad batteries/chargers at the beginning.
Some authority is better than no authority! :) Hmm, exploding batteries do seem deadly. Just did some research and they don't look fun. I've bought 15+ batteries from Thrunite before though and have had no issues, but it would be good to check any new brands that I get.

-Mark
 

aznsx

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I've bought 15+ batteries from Thrunite before though and have had no issues...

...and I guess you're talkin' about needing something like this?


If so, it's IMR (as recommended), (EDIT: is 15 A continuous rated), is protected, gives you single vendor point of support / responsibility, and is a brand you trust. I'd do it.
 
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Marquis07

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That is 100% the battery I have in mind and is also the exact one that's in my 18650 lights. :) But I'll have to get it from battery junction because I'm in Canada. Thanks man!
 

Marquis07

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...and I guess you're talkin' about needing something like this?


If so, it's IMR (as recommended), (EDIT: is 15 A continuous rated), is protected, gives you single vendor point of support / responsibility, and is a brand you trust. I'd do it.
That is 100% the battery I have in mind and is also the exact one that's in my 18650 lights. :) But I'll have to get it from battery junction because I'm in Canada. Thanks man!
 

aznsx

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That is 100% the battery I have in mind and is also the exact one that's in my 18650 lights. :) But I'll have to get it from battery junction because I'm in Canada. Thanks man!
I'm not shillin' for BJ, but that's where I get a LOT of mine, and have for over a half dozen years now. Edit: They're professionals.
 
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Lynx_Arc

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Some authority is better than no authority! :) Hmm, exploding batteries do seem deadly. Just did some research and they don't look fun. I've bought 15+ batteries from Thrunite before though and have had no issues, but it would be good to check any new brands that I get.

-Mark
As there are but a few battery manufacturers most batteries sold not under their label/stamp are resleeved. Sometimes you get the off name labels cheaper than the batteries from the manufacturers sometimes more expensive. There are also chinese batteries that are more miss than hit on the quality/specs. I have a cheap walmart Onn power bank with chinese cells in it that from what I've heard aren't bad but I haven't tested them.
 

Marquis07

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As there are but a few battery manufacturers most batteries sold not under their label/stamp are resleeved. Sometimes you get the off name labels cheaper than the batteries from the manufacturers sometimes more expensive. There are also chinese batteries that are more miss than hit on the quality/specs. I have a cheap walmart Onn power bank with chinese cells in it that from what I've heard aren't bad but I haven't tested them.
As far as I can tell, the Thrunite batteries I have are actually Samsung 30Q under the wrapper. I could not find any Samsung batteries that have 3100mah at 15 A. https://www.imrbatteries.com/samsung-30q-18650-3000mah-15a-battery/
Does this mean that Thrunite is lying by claiming that the batteries have 3100mah when they only have 3000? Also, none of Samsung's batteries are protected. What are the chances that Thrunite added a circuit to the batteries, or are they lying in saying the batteries are protected when they're not?
Thanks,
Mark
 

aznsx

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As far as I can tell, the Thrunite batteries I have are actually Samsung 30Q under the wrapper. I could not find any Samsung batteries that have 3100mah at 15 A. https://www.imrbatteries.com/samsung-30q-18650-3000mah-15a-battery/
Does this mean that Thrunite is lying by claiming that the batteries have 3100mah when they only have 3000? Also, none of Samsung's batteries are protected. What are the chances that Thrunite added a circuit to the batteries, or are they lying in saying the batteries are protected when they're not?
Thanks,
Mark
This is sort of general response to the issues you raise.

Cells produced by the primary, basic cell manufacturers are produced for a wide variety of applications, of which flashlights is not the primary one, that being more of a 'niche' application.

Flashlight manufacturers want to sell and provide cells to their customers as part of a total product solution for flashlight users. They spec and test / qualify a basic cell that meets all their requirements for use with their products, then contract with a supplier to optimize it for use by their flashlight customers by providing / adding a safety (protection) circuit module, sometimes USB charging circuitry, etc. They then 'package' the product with a wrapper / label for the flashlight manufacturer and provide it to them as an OEM product for the flashlight producer to market with their flashlights, and critically, one they have the confidence in to put their valuable name on.

This is what all the U.S. flashlight manufacturers I'm aware of who sell Li ion cells in their product line do (like Surefire, Streamlight, etc.), and also 'off-shore' flashlight manufacturers with a major U.S. market presence (Fenix, Thrunite, etc.) Offhand, I can't think of any exceptions. They do the specification, testing, qualification work, and choose an OEM supplier who can provide a product that meets their standards to provide it. The flashlight manufacturer has all the incentive in the world to ensure that all that's involved in this OEM process is done to a standard that they are prepared to put their good name on, as their reputation then depends on that. I have a single point of contact / support / responsibility, and specifications, and it's the company whose name in on the finished product.

This is, in general, not unique to flashlight manufacturers. This is pretty much the way industry works. Not every product manufacturer can produce every part of their product that's required. The thing that makes flashlights and cells a somewhat special category is the fact that the cell is a visible and user-replaceable part of the product which they sell separately, and which has their name on it. Many OEM parts in many products do not bear the name of the end product producer on them, which makes the case with flashlights and cells different from some other things (such as a hydraulic valve used in the guts of my car, for example).

I'm an electronics industry technical professional, so this is SOP for me. However, I do not try to reverse-engineer products, much less components of products, to determine their suitability. I buy flashlights from suppliers I have confidence in, and I have confidence in them to do their work correctly and up to a certain standard (which in my case is fairly high). I have confidence not only in the 'top level assembly' product that I purchase, but also its component parts and replacement parts, including those produced for them by OEM suppliers. If I didn't, I wouldn't buy their product (in this case flashlights). I have confidence that these products generally perform as advertised and meet their stated specifications / ratings.

In other words, I rely on the manufacturers / suppliers of the products I buy to not only know what they're doing, but to do what they claim to do, and do it properly. If I trust them to build / produce my flashlight, I trust them to do the rest of their jobs properly as well. Again, if I didn't, I wouldn't be buying their products.

I do test the cells I buy using basic equipment (such as so-called analyzing chargers) to 'sanity check' this stuff to ensure that it performs within a reasonable tolerance of claimed performance. These cells are also independently tested by others more exhaustively, and I also rely on their testing for further confirmation. Empirically and from my experience, I've found that I'm generally getting what I'm paying for, the products do tend to perform close to specification, and I've evidently done a pretty good job of choosing my suppliers / manufacturers so far! EDIT: Note that I do use OEM cells provided to one manufacturer in another flashlight manufacturer's flashlights (I'll use Fenix-branded cells in a Streamlight flashlight, for example), but that doesn't change the basic principles here, it's just an extension of them.

One shouldn't need to reverse-engineer products they buy to determine their suitability. I don't, nor do I have time to do that, nor do I want to. I'm paying my supplier / manufacturer to do that work. I pay a bit more for the cells I buy to get that, but I'm getting my money's worth for what I spend.
 
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Lynx_Arc

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As far as I can tell, the Thrunite batteries I have are actually Samsung 30Q under the wrapper. I could not find any Samsung batteries that have 3100mah at 15 A. https://www.imrbatteries.com/samsung-30q-18650-3000mah-15a-battery/
Does this mean that Thrunite is lying by claiming that the batteries have 3100mah when they only have 3000? Also, none of Samsung's batteries are protected. What are the chances that Thrunite added a circuit to the batteries, or are they lying in saying the batteries are protected when they're not?
Thanks,
Mark
WIthout going into depth they could likely be 30Q batteries. Ratings on everything usually has a defined range of which is the "norm" for them to fall into. Batteries often list a percentage of the rating that defines the range and It is possible that the 30Q test out to be a little more than that and are within the range of 3100mah on average as 100/3100 is about 3% within range of 3000 and if a cell is let's say 3050 that would be about 1.5% off 3100mah. It is also possible that they have been able to slightly improve the battery manufacturing process to get 3100mah too as that isn't a huge leap when we have 3400-3500mah rated batteries that have less Amp ratings. My thoughts on this is a balance of cost vs ease of replacement vs usage overall making it that you may well get by with a 2600-2800mah battery rated at 20A that costs enough less to be more bang for the buck vs slightly higher capacity that under heavier loads may have a slightly higher internal resistance that cancels out some of the extra power anyway. Thinking about a single battery in a device vs multiple replaceable batteries backing up the one in use is where I think you should consider dwelling. It may mean replacing batteries 10% more often but also may mean you have 20% more runtime per dollar spent on them plus each additional battery over the less higher capacity batteries you would have spreads out the cycle usage more meaning you may find that you are end up in the long run not having to buy new batteries as often which could be even more savings.

Personally I like the idea of 3000mah in an 18650 it just sounds better than 2600 or even 2900 to me but the one 3000mah battery I have (sofirn) has not impressed me over time it has greatly dropped in capacity with less than 100 charge cycles I think it has dropped to around 2200mah but likely because I charge to 4.2v instead of 4.1V.

As for the Thrunite battery being protected it is not an OEM battery a protection circuit could be added as they are (I think) rewrapping it anyway. They can add USB charging to a battery. The easiest way to check for protection is length of battery usually a protection circuit adds considerable length to an 18650 so instead of about 65mm long it is 68 to maybe close to 70mm long. If it has a button top that can add a little too.

Protection circuitry can limit the cells ability to provide high current also as protection circuitry varies there are boards that offer in the 5A range (maybe 3.5A even?) and 10A and perhaps higher I'm not really familiar with these specs I've only heard such things in passing in the forum where people have been using high drain lights and find they cannot hold turbo outputs and discover the culprit is both the protection circuit. Protection circuits can cut power if tripped but also those not designed for higher currents can add enough resistance into the equation to throttle high current output devices down. I would think a 15A rated protected battery is probably good for 10A easy continuous and may do 15 continuous but it is possible they could put only a 10A circuit in it figuring nobody would need more if the rating were hidden and folks were relying on the ratings of the battery itself.
 

Marquis07

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They spec and test / qualify a basic cell that meets all their requirements for use with their products, then contract with a supplier to' optimize it for use by their flashlight customers by providing / adding a safety (protection) circuit module, sometimes USB charging circuitry, etc. They then 'package' the product with a wrapper / label for the flashlight manufacturer and provide it to them as an OEM product for the flashlight producer to market with their flashlights, and critically, one they have the confidence in to put their valuable name on.
Of course that makes sense. I assumed each individual seller, eg. Thrunite would simply wrap their own batteries, but it would be way more efficient for the supplier to configure the batteries like you said.


In other words, I rely on the manufacturers / suppliers of the products I buy to not only know what they're doing, but to do what they claim to do, and do it properly. If I trust them to build / produce my flashlight, I trust them to do the rest of their jobs properly as well. Again, if I didn't, I wouldn't be buying their products.
That's a very good point. Really, it comes down to a $10 battery vs a $20 battery, and I'm fine with spending an extra $10 to get the official battery.


Thinking about a single battery in a device vs multiple replaceable batteries backing up the one in use is where I think you should consider dwelling. It may mean replacing batteries 10% more often but also may mean you have 20% more runtime per dollar spent on them plus each additional battery over the less higher capacity batteries you would have spreads out the cycle usage more meaning you may find that you are end up in the long run not having to buy new batteries as often which could be even more savings.
Yes, I get what you're saying. Ideally, I want to have multiple spare batteries for each flashlight, so I'll just buy a few extra when I get them. It's not like they have a best before date. XD


My thoughts on this is a balance of cost vs ease of replacement vs usage overall making it that you may well get by with a 2600-2800mah battery rated at 20A that costs enough less to be more bang for the buck vs slightly higher capacity that under heavier loads may have a slightly higher internal resistance that cancels out some of the extra power anyway
All of the lights I have "Turbo" mode that is super bright for a short time period. Normally I don't use this feature for any length of time, so I'm guessing the battery would supply only about 10 A regularly.


Personally I like the idea of 3000mah in an 18650 it just sounds better than 2600 or even 2900 to me but the one 3000mah battery I have (sofirn) has not impressed me over time it has greatly dropped in capacity with less than 100 charge cycles I think it has dropped to around 2200mah but likely because I charge to 4.2v instead of 4.1V.
I'm going to stick with Thrunite batteries for now, but if I was to get some lower capacity like 2600-2900, is there anything you would recommend?


The easiest way to check for protection is length of battery usually a protection circuit adds considerable length to an 18650 so instead of about 65mm long it is 68 to maybe close to 70mm long. If it has a button top that can add a little too.
Yep, the battery is exactly 70 mm to the end of the button top.






Thanks for the replies!
Mark
 
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