A Beginner’s Guide to Lithium Batteries- Rev 3

Have posted this before on the old sites, but since they no longer exist figured it was time to bring it here. Besides the world of lithium based batteries is always changing. This is third version of this guide, and at some point know they’ll be a version 4. For now though it’s as up to date as possible.

When it comes to vaping there are really only three types of batteries to focus on- ICR, INR, and IMR*1. All three are lithium based, run at 3.7v nominal (4.2 fully charged), and come in the same sizes*2. So what are the differences between the three?

ICR (lithium cobalt rechargeable)-

ICR is not safe chemistry. They can/will vent with high pressure gas and flames, and possibly explode if they go into thermal runaway. (Which is why most of them ship with protection circuits. This adds length. A 3400mah efest 18650 for example is actually 71mm long, making it an 18700 technically).

They are low drain*3 in most cases, meaning they are best suited only for flashlights or other applications not requiring a lot of current. Not recommended for regulated variable voltage/wattage devices, or when using a Kick in a mechanical mod due to their low amp limit, typically less than 7 amps on an 18650. Pushing a battery past its amp rating can cause it to go into thermal runaway or trip the circuit. For the same reason they can’t be recommended for any sub-ohm applications.

ICR cells also have a steady dropping voltage curve due to their higher internal resistance. Meaning they quickly drop from 4.2v at full charge to 3.7v then it flattens a bit until 3.5v and drops rather quickly from there again.

ICR batteries used to be the only cells recommended for use in mechanical mods, though that has changed over the years, especially when it comes to sub-ohming. Reason being was the protection circuit. This helped prevent people from having a thermal issue if they ran too low an ohm or over-drained their cells. Despite the growing popularity of sub-ohm tanks, I still recommend their use in a mechanical for new users (only if it’s a protected ICR cell). At least until they get used to the flavor change associated with low voltage (meaning time to charge) for safety reasons. The lone true advantage of ICR over IMR is the capacity.

IMR (lithium manganese rechargeable)-

These are safer chemistry. IMR batteries, because of the addition of manganese and removal of cobalt to the chemistry, are inherently safer than ICR cells. They may still vent in thermal runaway, but are less likely to do so due to a higher heat tolerance. Not likely to vent with flames or to explode, but when they do it’s far more spectacular (in a bad way) than with an ICR cell.

Higher amp limit. These are often referred to as high drain cells*3. They are preferable to ICR in mods and devices that require a lot of power like the Provari, DNA based mods, SX3xx based mods, and the like. With mechanicals and RBA’s they allow people to get higher current with using lower ohms*4*5.

IMR cells have a lower internal resistance, which translates to a much more dynamic voltage curve in comparison to ICR. These will stay above 3.8v under load for a higher majority of their charge cycle, and then drop rather quickly afterward. This gives them a higher useable mAh*6 than their ICR brethren.

INR (lithium nickel rechargeable)-

The next step in high drain cell technology. Samsung is, as of right now at least, at the forefront of this chemistry. It’s theoretically safer than IMR (though again when they fail they do it in the same fashion as the IMR), not to mention more powerful. It’s conjecture at this point, but with the right manufacturing techniques they could hold 3 1/2 times the amount of energy per pound as any other lithium ion chemistry currently being used.

That being said we’re not there yet. Samsung INR cells are rated for 25A discharge with active cooling (20A without)*10, have capacities up to 2500mAh, and perform very well at a 5A current. Problem is they do not last long. According to the spec sheet they lose 40% capacity at 250 charges, in my own testing it’s closer to 30% but usually ran them at 5-7 amps. Have known people who ran to the their upper amperage limits who only got 100-150 charges before the cell lost 40-55% capacity. It’s hard for me to recommend then because of this. You’ll go through twice the number of INR cells in comparison to IMR cells.

Their voltage curve is almost a hybrid of ICR and IMR. They do start on load as high as IMR cells, but they also don’t drop as dramatically after 3.8v. It’s much more similar to that of an ICR curve at a slightly higher voltage.

Cell Quality-

Not all ICR, INR, and IMR cells are created equal though. This is where the supplier/manufacturer comes into play. There are quite a few different makers, some you can trust some you can’t. Will give a quick rundown of them and what makes them better.

AW- In terms of cells these are the highest quality available. Andrew Wang used to work for Panasonic, developed his own company, and is the top provider of cells to flashlight users (and of course now vapers). He gets the top 5%*7 of cells from Panasonic, Sanyo, etc. and puts his custom PCB on ICR cells. Cells routinely last 500 charges or more if handled properly*8.

Efest- Top 10% of cells from the same manufacturers as AW, though also gets cells from LG (top 15%) and Sony (top 15%). These do not last as long as as AW, but perform as well over the first 150 charges. Usually last 250-300 charges*8. As with the recent trend, another knock on Efest is their over stating of their amp limits on a lot of their high drain batteries.*10

LG- Top 10% of cells are sold as bare cells to consumers. The top 5% are reserved only for cars, phones, laptops. They have improved their cell quality and chemistry over time. Would put them one notch below AW, but right up there with the other big battery manufacturers.

Samsung- Usually only top 10% of cells are available to consumers. Top 5% are reserved for laptops, tools, and car companies. They specialize mainly in INR and ICR chemistry. Samsung cells out perform Sony, but due to INR still being in it’s infancy the cells do not last as long as their IMR brethren. This applies especially if using them in high amperage situations. *10

Sony- Usually only top 10% are available to consumers, though they have sold a few top 5% when a new cell (like the VCT4 or 5) first gets released. Average life span is usually 350-450 charges*8. The only issue with Sony is they have exaggerated amperage numbers on the VCT4 and 5, though not through fault of their own*10. Another good cell, one notch below AW or Panasonic. *11

Panasonic- Top 10% of calls are sold to consumers, save for hybrid IMR (like the 2900mAh) cells which are top 5%. These cells can last 400-500 charges*8, and are considered the next best cells to AW.

IMREN (formerly MNKE)- Top 10% are available to consumers, their top 5% are reserved for car companies only. Since IREN bought out MNKE can no longer call them a top cell manufacturer. Not because they are no longer making good batteries, but because the bare cells sold to the public are grossly over inflated when it comes to their amp ratings*10.

Sanyo (owned by Panasonic)- Top 10% of cells available to consumers. Again ranks with Panasonic cells in quality. Last between 400-500 charges*8.

Trustfire- Uses top 20% of LG, top 20% of Panasonic, top 20% of Sanyo. These are considered cheaper cells, but still decent. Usually get 200-300 charges out of them*8. Trustfire is a re-labeler like efest and AW but uses lesser quality cells. Avoid if possible. Has been known to lie about capacity on certain cells.

Ultrafire- Uses cells that are under 20% from a number of manufacturers, or worse pulled cells of unknown origins. Infamous for using inflated mAh numbers, should be avoided at all costs.

Smoktech- See Ultrafire

Joyetech- Uses top 15% of cells from Sanyo in some of their 18650’s, otherwise uses under 20% cells from Sanyo. Again should be avoided*9.

Generic cells- Come in blue, green, red, or yellow (haven’t seen any other colors but sure they’re out there) labels with just the size, capacity, and voltage. These should be avoided at all costs. Not only are they under 20% cells from any source, they also can be old cells pulled from a laptop and relabeled, or smaller batteries put into casings to make them bigger. No telling what you’ll get with these.

Fakes- Something you have to look out for, especially when it comes to AW and Efest. Trustfire is another company that gets fakes made of them quite constantly. These are generic cells made to look like a name brand. It’s why you should only get cells from a reputable dealer if you’re a vendor, and if buying from a vendor be sure it’s someone you trust. Most cells found on ebay are fakes (again especially with AW). AW cells use holographic stickers to combat this along with other markings. can’t stress this enough- BUY FROM A TRUSTED SOURCE.

There are more companies out there, but mainly in the flashlight world. KeepPower, Xtar, and Callie’s Kustoms to name a few of the re-labelers. Most of these use top 10-15% from Sony, Panasonic, LG, and Sanyo (save for Callie’s Kustoms which use top 5% for their 2250mAH hybrid cells, and Xtar which at one point got the top 5% of Sony VCT4’s). Simply too many to list and for vaping purposes don’t need to get too much into detail on them.

Special notes

*1- The fourth type (LiFePo- lithium iron polymer) was popular in the early days of vaping but has all but disappeared in mods with replaceable cells so there’s no need to delve too far into them. You will still find them in certain sealed boxed mods, or ones that use hobby style battery packs. These have high capacity and amp limits depending on the design than the cylindrical cells, but a quick youtube search will show you what happens when they fail from overcharging or abuse.

*2- MM circumference, length, shape. 18650 is 18mm around, 65mm long, and because it’s a round cell 0. 18490 is 18mm, 49mm, and 0.

*3- This involves the C (current) rating. The manufacturer will determine the C rating on the cell (or in protected cells the circuit determines it). C*mAh= maximum current. Example a 3400mAH cell at 2C = 6.8amp max current. A low drain cell will have a low C rating. Most protection Circuits only have a 2C rating. High drain cells have a much higher C rating and thus can put out anywhere between 10a-35a on an 18650 cell.

*4- Ohm’s law is one of the most important equations to a vaper. It’s simply volts divided by resistance equals amps. Amps times volts equals watts. This is something you want to keep in mind at all times when selecting what connection type and battery you purchase. If we think of power in terms of a water faucet voltage is the amount of water, resistance is how open or closed the valve is, and amperage is the flow of water. The more open the valve the faster the water flows.

*5- Sub-ohm’ing has become rather popular as of late. That’s when you run a resistance lower than 1.0 on a device. This can be a dangerous set up if you don’t use the right cells in a mechanical or unregulated mod. Not suggested for a novice user.

*6- Amount of mAh before the battery hits 3.2v or end of charge. Example an AW IMR 18650 1600mah cell still has ~295mAh at 3.2v in my testing, while a AW ICR 18650 3100mAh has ~595mAh at 3.2v. Meaning the IMR cell has 1305 useable mAH, while the ICR has 2505 useable mAh.

*7- Batteries like all electronics are binned. The higher the bin the better they perform. Top 5% usually goes to cell phones, laptops, and cars. 10% goes to power tools and certain battery powered appliances. Anything under 10% go to lesser manufacturers, anything under 20% is considered a cheap cell.

*8- Never deep cycled, never exposed to high temps for long term period (90 or above), stored properly (3.6v long term charge), or overcharged.

*9- Doesn’t apply to their sealed batteries like the eGo C twist.

*10- Recently companies are putting the burst amperage limit or active cooling limits on their batteries and selling them as such. Sony is an exception. The VCT4/5 in the spec sheet both state that they require active cooling for anything over 20A. They were never meant for vapers, and did not advertise them as such. It was vaping companies that labeled them 30A cells. Efest and IMREN are two of the worst perpetrators of this practice. There is no cell on the market rated for 2000mAh capacity or above that can do above 20 amps continuous without active cooling. Burst ratings are just that, they can do a high amperage for 2-5 seconds, but more than that you begin to damage the cells. You want to run batteries at their continuous rate, never for their burst. This is the danger of sub-ohming and not knowing the ins and outs of your batteries.

*11- Sony no longer is making VCT4/5 cells for consumers. All cells being purchased/sold are either old or fakes. There are some updates to come in the near future on this, but for now can’t say anything else.


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