Earlier this year i was sent a box of Efest cells to test by a long term and well respected customer in the vaping industry who was keen to get an understanding of the product they were supplying. An admirable move by a business in an industry that preaches battery safety but doesn’t always have the means/knowledge to show what is and isn’t safe and i was pleased they reached out for assistance.

Heres what happened…

Unboxing – The packaging I have to admit is good. Packed in pairs and/or individually cased (albeit more for display than protection) the packaging meets basic requirements for air or ground shipping in terms of security and isolation of cells. It’s nice to see a decent list of warnings on their use on the side in legible English. As a product you can take out of a box and put straight on a store shelf, so far so good…

Wraps, insulators and general appearance – Overall the cells are visually appealing. I have no shame in admitting that my favourite colour is actually purple which they all are. Warnings are repeated on the cell wraps which is great and it also includes almost all of the information required to be compliant with EU/UK battery legislation (missing the Li-ion marker). They appear to replace all of the insulators with their own matte black plastic ones. Not sure why but its no issue.

So now the juicy bit. How did they perform? 

Efest 18500 1000mAh 15A

Picture of Efest 18500 1000mAh 15A Discharge Test

Efest 18500 1000mAh 15A Discharge Test

Test 1 carried out with Cell “1” – Capacity Test @ 5Amps

  • Start Voltage 4.190v
  • Ambient Temperature 23’C
  • End Temperature 38.9’C
  • End Voltage 2.81v
  • Capacity Delivered 996mAh

*This test is solely for capacity, to ensure the cell delivers the amount of energy it promises on the wrap. 996mAh is a good result for a 1000mAh rated cell, especially at a third of its maximum discharge rating.

Test 2 carried out with Cell “2” – Discharge Test @ 10Amps

  • Start Voltage 4.194v
  • Ambient Temperature 23.2’C
  • End Temperature 51.6’C
  • End Voltage 2.80v
  • Capacity Delivered 984mAh

Test 3 carried out with Cell “1” – Discharge Test @ 15Amps

  • Start Voltage 4.196v
  • Ambient Temperature 24.1’C
  • End Temperature 73.4’C
  • End Voltage 2.83v
  • Capacity Delivered 1030mAh

Interestingly Cell 1 delivered a very slightly better capacity on the second charge and discharge but only by fraction. I would rate this cell at 1000mAh with a 12A CDR (constant discharge rate) based on its performance and temperature. The maximum continuous rating of 10A is perhaps slightly conservative but as there is currently no international standard for pulsed discharge rating, I think this one can be ignored and it is perfectly safe to accept Efest’s own 10A rating. Given the final temperature of the cell during testing at 15amps, no further tests were carried out. They would only serve to damage the internal chemistry of the cell and would be above the widely accepted maximum operating temperature of 80’C for lithium-ion cells. I’m not able to ascertain what cell is used under the wrap of this one.


Efest 18650 3500mAh 20A

Picture of Efest 18650 3500mAh 20A Discharge Test

Efest 18650 3500mAh 20A Discharge Test

Test 1 carried out with Cell “1” – Capacity Test @ 5Amps

  • Start Voltage 4.196v
  • Ambient Temperature 21.1’C
  • End Temperature 37.9’C
  • End Voltage 2.82v
  • Capacity Delivered 3115mAh

*This test is solely for capacity, to ensure the cell delivers the amount of energy it promises on the wrap. 3117mAh is a good result for a 3500mAh rated cell being tested at 5A. While the graph shows it as a failure, I set the bar at 90% and discharged to 2.8V and it still achieved 89.1%.

Test 2 carried out with Cell “2” – Discharge Test @ 10Amps

  • Start Voltage 4.198v
  • Ambient Temperature 21.6’C
  • End Temperature 71.1’C
  • End Voltage 2.81v
  • Capacity Delivered 2854mAh

The above is a good piece of data for a cell operating comfortably at its limit.

Test 3 carried out with Cell “2” – Discharge Test @ 15Amps

  • Start Voltage 4.196v
  • Ambient Temperature 24.1’C
  • End Temperature 89.3’C
  • End Voltage 2.83v
  • Capacity Delivered 1878mAh

This is a strong cell in terms of energy density, but overrated on discharge ability. While the graphs shows a failure for capacity, it was a reasonable effort for a 10A rated cell discharged at 5A down to 2.8V. Factory capacity tests are carried out at 0.2c (0.2c of 3500mAh equals 0.7A). I am 99% certain this is an LG cell, most likely a MH1 or MJ1. Im leaning towards the MJ1 given Efest’s 3500mAh capacity rating. Perfect for mouth to lung set ups at low wattage (under 30w) or in a low wattage dual battery device. The 20A “pulse” discharge is useless because there are no set standards for testing this and putting it as the larger number on the cell is a bit of a daft move by Efest in my opinion. Although it states in smaller text that it is only 10A constant, because more prominent text shows 20A, I ran testing past 10Amps. As you can see, at only 15A the initial voltage sag was extreme and the cell temperature reached 89’3C. This was pushing the cell beyond its limit and no further tests need be carried out. Irreparable damage will have almost certainly been caused to this cell’s internal chemistry by this test.


Efest 18650 2600mAh 40A

Picture of Efest 18650 2600mAh 40A Discharge Test

Efest 18650 2600mAh 40A Discharge Test

Test 1 carried out with Cell “1” – Capacity Test @ 5Amps

  • Start Voltage 4.189v
  • Ambient Temperature 17.7’C
  • End Temperature 32.1’C
  • End Voltage 2.80v
  • Capacity Delivered 2345mAh

*This test is solely for capacity, to ensure the cell delivers the amount of energy it promises on the wrap. 2345mAh is a good result for a 2600mAh rated cell down to 2.8V.

Test 2 carried out with Cell “1” – Discharge Test @ 15Amps

  • Start Voltage 4.188v
  • Ambient Temperature 20.2’C
  • End Temperature 70.2’C
  • End Voltage 2.80v
  • Capacity Delivered 2435mAh

Test 2 carried out with Cell “2” – Discharge Test @ 25Amps

  • Start Voltage 4.188v
  • Ambient Temperature 20.2’C
  • End Temperature 100.4’C
  • End Voltage 2.80v
  • Capacity Delivered 2295mAh

This is a very bad result. I only allowed this test to continue above 90’C on the basis that the final 10’C increase happened as it was rapidly approaching 2.8V and I wanted to see if it would actually make it.

No further tests will be conducted on this cell. It runs far too hot at 25A for this to be its actual maximum discharge rating and certainly cant be used at the 40A printed in bold/larger text. On initial inspection and from the ratings given I had quickly assumed that this might be a re-wrap of the Sony VTC5A however the above test shows this isn’t the case. On further inspection, it has a vent perforation design under the positive cap that I haven’t seen before and doesn’t match any Sony cells we have tested previously. The capacity of the two cells also appears to be wildly different. Given the temperature at 15A and 25A, I would estimate this cells true CDR to be around 17-19A.


Efest 18650 3000mAh 35A

Picture of Efest 18650 3000mAh 35A - Discharge Test

Efest 18650 3000mAh 35A – Discharge Test

Test 1 carried out with Cell “1” – Capacity Test @ 5Amps

  • Start Voltage 4.196v
  • Ambient Temperature 19.8’C
  • End Temperature 30.4’C
  • End Voltage 2.80v
  • Capacity Delivered 2755mAh

*This test is solely for capacity, to ensure the cell delivers the amount of energy it promises on the wrap. 2755mAh is a good result for a 3000mAh rated cell down to 2.8V. It would have hit 3000mAh. More on that below.

Test 2 carried out with Cell “2” – Discharge Test @ 20Amps

  • Start Voltage 4.199v
  • Ambient Temperature 20.3’C
  • End Temperature 74.8’C
  • End Voltage 2.803v
  • Capacity Delivered 2478mAh

Another good result for a cell operating at its limit comfortably. (Ignore the first Pass mark/red vertical line on the graph for this discharge. Capacity pass/fail was left on at 80% by mistake.)

Test 3 carried out with Cell “2” – Discharge Test @ 25Amps

  • Start Voltage 4.189v
  • Ambient Temperature 21.8’C
  • End Temperature 100.1’C
  • End Voltage 2.83v
  • Capacity Delivered 2260mAh

This cell performed well at the CDR given by Efest of 20A, however given the largest number on the wrap is 35A, I was keen to see how close it would get. At just 5Amps more than the CDR, it hit over 100’C right at the end of the test. I had a feeling this might be the case, because the cell under the wrap is a Samsung 30Q. Samsung rate the cell at 15A on their datasheet but they are well known to be 20A capable, proven above. Although it only delivered 2755mAh in capacity testing, Samsungs test parameters for reaching the full 3000mAh is a discharge from full (4.2V) at 1.5A, down to 2.5v. I have every confidence it would make that. In short this is a good, well known cell in different clothes, wearing an unfortunate rating. If they had put the CDR in bold instead of a useless pulse discharge rating, this would be a perfect cell.


Efest 20700 3100mAh 30A

Picture of Efest 20700 3100mAh(30A) - Discharge Test

Efest 20700 3100mAh(30A) – Discharge Test

Test 1 carried out with Cell “1” – Capacity Test @ 5Amps

  • Start Voltage 4.173v
  • Ambient Temperature 20.8’C
  • End Temperature 28.9’C
  • End Voltage 2.80v
  • Capacity Delivered 2749mAh

*This test is solely for capacity, to ensure the cell delivers the amount of energy it promises on the wrap. 2749mAh is a reasonable result for a 3100mAh rated cell down to 2.8V. A deeper discharge (to 2.5V) would have seen a better result but a 5A drain on a 3100mAh 30A rated cell should have seen closer to 3000 really. I would estimate its true capacity being around 2900mAh and likely 20A discharge

Test 2 carried out with Cell “2” – Discharge Test @ 15Amps

  • Start Voltage 4.199v
  • Ambient Temperature 21.’C
  • End Temperature 59.1’C
  • End Voltage 2.80v
  • Capacity Delivered 2785mAh

At 59.1’C, we’re already approaching this cells maximum constant discharge rate. On that basis, the capacity no longer looks so much of a poor effort.

Test 3 carried out with Cell “1” – Discharge Test @ 20 Amps

  • Start Voltage 4.196v
  • Ambient Temperature 20.4’C
  • End Temperature 74.3’C
  • End Voltage 2.801v
  • Capacity Delivered 2708mAh

I considered going straight for the cells maximum discharge rate on this test, but given the previous test having got to 59’C at half of 30A, I decided to do an intermediate. This was also on the basis that Mooch has also tested this cell and found its true limit to be 20A. Based on the above, I have to agree. 74’3C is a nice, safe working CDR for this cell.

Test 4 carried out with Cell “2” – Discharge Test @ 30 Amps

  • Start Voltage 4.196v
  • Ambient Temperature 20.4’C
  • End Temperature 91.8’C
  • End Voltage 2.801v
  • Capacity Delivered 2587mAh

As expected, the 4th test carried out at the only figure provided on the wrap ran hotter than it should, indicating that both my previous thoughts and Mooch’s testing tally up. This is an overrated 20A cell and 30A is asking too much of it. I believe I have actually seen this cell elsewhere, from a Chinese battery manufacturer rather than one of the big OEMs (Samsung, Sony etc) Unfortunately and annoyingly I have forgotten which one.


Efest 21700 3700mAh 35A

Picture of Efest 21700 3700mAh 35A - Discharge Test

Efest 21700 3700mAh 35A – Discharge Test

Test 1 carried out with Cell “1” – Capacity Test @ 5Amps

  • Start Voltage 4.173v
  • Ambient Temperature 20.8’C
  • End Temperature 29.1’C
  • End Voltage 2.80v
  • Capacity Delivered 3404mAh

*This test is solely for capacity, to ensure the cell delivers the amount of energy it promises on the wrap. 3404mAh is a reasonable result for a 3700mAh rated cell down to 2.8V.

Test 2 carried out with Cell “2” – Discharge Test @ 20Amps

  • Start Voltage 4.186v
  • Ambient Temperature 22.3’C
  • End Temperature 68.7’C
  • End Voltage 2.80v
  • Capacity Delivered 3342mAh

Test 3 carried out with Cell “1” – Discharge Test @ 30Amps

  • Start Voltage 4.196v
  • Ambient Temperature 17.4’C
  • End Temperature 81.6’C
  • End Voltage 2.83v
  • Capacity Delivered 2987mAh

Another good cell, with a slightly over-zealous rating. I suspect the full capacity would have been reached with a 0.2C discharge down to 2.5v so we can probably agree this is a 3700mAh cell but given the 81’C temperature at 30A, we’re at the top end of this battery’s ability and I rate it no further than this. A further unlisted test at 35A reached 96.4C. Again, this mirrors testing done on the same cell by Mooch.

So, what do we think? – Visually appealing products, very well packaged for the retail market but they’re still showing some marketing immaturity in their continued use of ratings alone to sell batteries where Vapcell have gone in the right direction and made their name selling accurately rated but “first to market” and (initially at least) hard to find cells (VTC5D, VTC6A, 20S etc). Some of the cells tested here are good cells. They dont need a trumped up rating to sell if the price point is right but i can 100% see why they do it and its motivation lies in profit. How do you make a Samsung 30Q which can be purchased almost anywhere for circa £4-5 these days, worth £8? You slap a shiny purple wrap on it and give it a 35A rating. That’s how. Like with almost all companies re-wrapping cells, they are selling you a product you can buy elsewhere for less money and to do that, you need to add value. The problem here lies between actual value, and perceived value. You think you are getting more value because outwardly, it appears to perform better but look above. Look at the actual ratings, look at the price of that cell, then compare it to an OEM cell from Samsung, Sony, LG.  Chances are, you can get the same cell or better, at a better price.

Do you have any thoughts? Is there some value in these products that i’ve missed? Let us know in the comments below

Ben – Sales Director

Picture of Fake Samsung 25R 18650

Fake Samsung 25R 18650


It’s come to our attention through our network that there are a large number of counterfeit Samsung 25R (and potentially 30Q) cells either already on/about to land on the market in the UK.

There’s a possibility that they are re-wrapped Samsung 22P cells with a 25R/30Q wrap on them.


What to look for

Firstly, the wrap – Having another (known genuine) 25R/30Q would be advantageous here. Re-wrapped cells rarely have the same consistency as an OEM product. They are normally slightly off colour, have a different texture and almost always a differing thickness. Samsung wraps are known to be thicker but much softer than most.

Positive end crimp vent disk and insulator

Picture of Samsung 25R positive crimp

Samsung 25R positive crimp

 The Samsung 25R and 30Q vent disk (under the positive 3 point post) has a dimple in the centre, surrounded by a complete circle score mark. Outside of this is a further score line circle with a 2mm break. Directly opposite this break at the other side of score line will be a letter and number stamped into the disc. Counterfeit cells may differ. If they are a 22P, they will be accompanied by 3 radial score lines from the centre outward. The Samsung 25R AND 30Q have NEVER had these radial scores. Insulator should be flat gloss white (no texture), plastic and not adhered to the can.

Cell can markings

Picture of Cell can markings

Cell can markings

Samsung use an often evolving code system but one part remains the same. Near the top of the can will be two lines of code. The top should be 4 characters (Normally starting with a letter than a number). Directly below will be another line, more often with 5 characters.

On the Samsung 25R, the second character of the top line will be a number 5. On the 30Q it will be a 0. (Not  on its own a guarantee of a genuine cell because the 35E for example will also carry the “5” characteristic but we’re adding up the odds here)

Bottom Stamp

Picture of Samsung 18650 30Q Negative Marking

Samsung 18650 30Q Negative Marking

Samsung started stamping their cells with a unique identifier some time ago but this hasn’t extended to all of their range. You will however find a stamp mark under the wrap at the negative/bottom of the can. It can be a single character or a letter followed by two numbers. On this 30Q, its a single character, the greek “Epsilon”.  (Samsung often use Greek characters on the base of cans, the 25R previously having carried the “Theta” character)

Anything else to look out for?

Not unless you have access to or can test cells to the factory specification/standards against the datasheet. This is the only real way, along with the above factors, to ascertain whether or not a cell is what it says it is.

How can you protect yourself? 

Only buy these products from registered, legitimate businesses who can and do properly test the products for authenticity prior to sale. Bare cells sold to end users (vaping/torch industry etc) MUST BE COMPLIANCE MARKED.  Penalties for non-compliance are increasing and Trading Standards in the UK are actively pursuing this in 2019.

18650.UK is a fully compliant wholesale and end user/retail supplier of bare lithium cells. We batch test all cells even when buying direct from the manufacturer, compliance mark them in accordance with EU/UK legislation where required and provide you with a fully backed, genuine product.


Ben – Sales Director – 18650.UK

Thank you for purchasing cells for the “Build your own R2D2 kit” from Deagostini. We hope you’re very happy with them and excited for the final issues of the build if you’re not quite there yet! Get to know your product Before we get into the nitty gritty of battery safety, lets take a look […]

Following on from the recent “What is the best 18650 battery” blog post here, next up, we look at the chargers used for them.

“Which is the best charger” is another equally ambiguous question. With hundreds of choices of batteries and an ever growing list of manufacturers and specifications for chargers, the real questions and answers are very much the same. What do you want/need it to do, and at what price point?

To kick things off, we’ll look at function.

What should you consider when shopping for in a charger?

There are a few things you need as a minimum. Almost all chargers now come with reverse polarity, over charge and thermal protection. When choosing a charger, these should be the very least in terms of safety features that you should expect to see listed.  None of our chargers come without these.

What else? This will depend on the type of batteries you use, how many you have, and how fast you need to turn them around through the charger.

Lots of chargers now have 2Amp+ outputs in a portion if not all of their bays. The XTAR VP4 Plus Dragon that i use for example, will charge at 2Amps in the outer two bays. This is great for a quick turnaround of my favourite VTC5A batteries but not so great for my tiny RCR123A cells i use for lasers which prefer a 0.25A charge becuase its lowest setting is 0.5A. If you are unsure of what the charging limits are for your batteries, your supplier should always be able to supply you with the factory Datasheet. On there, you’ll find the maximum charging current. It’ll look like this;

Picture of LG HG2 18650 Datasheet

LG HG2 18650 Datasheet

As you can see, this is for the LG HG2 18650 battery. Its normal charge current is 1.25A so a normal 1Amp charge is fine but it will actually be fine with charging at upto 4Amps (many people are unaware of how high the current can be set for charging 18650 batteries. Some have upper limits of 8Amps!). Most chargers available to the public are not actually capable of topping out 18650 charging capacities.

The number of bays is also a worthwhile initial consideration. There’s no sense wasting money on a single bay charger if you use 4 or more batteries a day. In a fast moving world, something which offers the convenience of always having fresh batteries charged and available will save frustration. Consider the time it takes to charge your batteries and how many you need between charging. For me, i go through around 4 batteries a day so i have a 4 bay charger. This allows me to never have to worry about not having any ready. If you only use two each day, a 2 bay charger might be better.

Where you charge your batteries, or more so where you could charge them to make life easier is not a 100% necessary but certainly worthwhile consideration. The Nitecore range of battery chargers have been around longer than vaping and while their price point and robust design make them ideal for almost all uses, they’re hardly mobile; requiring a mains plug for operation. XTAR however, are very much mobile. Almost all of their main line of chargers are USB powered, taking a single or double micro USB power input meaning they can be used on the move and plugged into a car, a laptop, powerbank or anything else with USB power. Some can also be used the other way. Placing cells in it while unplugged, it can discharge them back out via USB output and act as a powerbank!

The normal features discussed above aside, some chargers go even further. Going back to my desk charger, the XTAR Dragon has an internal resistance check function. This is great for identifying any changes inside the cell or even faults. Among many others, it also has a discharge and refresh function, completely draining the battery then charging all the way back up. These functions do come at a higher price point but can prove useful for some users. Some chargers have Bluetooth monitoring (although i feel this is a bit of gimmick, because you should never leave charging batteries unattended). There is even a new charger coming from Efan in China (Efan Lux S4 Battery Charger) with a full LCD touch screen beside the charging bays. RRP on this is expected to be circa £149, an unprecedented amount for a 4 bay unit!)

Price – Budget is always key for retail buyers and you should always buy the best possible charger you can afford, from a reputable retailer. This goes some way to ensuring both good performance and reliability and as mentioned previously, should limit the need to buy more or upgrade in the future should your battery collection increase. Battery chargers have dropped in price considerably over the last few years and in a recent poll of over 2,000 of our customers, Nitecore and XTAR chargers came out on top with 88% of the votes between them. This is the result of their continued developments in spec and safety, along with overall design and performance.

Lastly, brand loyalty deserves a mention. Many people have a preferred brand, me included. Although we have traditionally exclusively supplied Nitecore products and only in the last year started supplying XTAR chargers, they have quickly become my favourite. Nitecore are a very good product at a very reasonable price point and my old D4 is still used at home 4 years on, but i prefer the aesthetic design of the XTAR products along with nicer screens and more data availability for very little extra in price.

You can find our full range of battery chargers from Nitecore and XTAR here

Of course, if you’re struggling to choose the right product for you we’re always available on email, or you can leave a comment below.


Ben – Sales Director.





This is a question we see a lot with sometimes ambiguous answers; whether or not you can take your 18650/lithium/vape batteries on holiday with you.

The short answer, is yes! There has never been a regulatory issue with taking batteries on holiday/abroad via air. That’s not to say there wont be in the future should people not abide by regulations set out by airlines. Should there be a rise in the number of incidents involving them, its probable that airlines will move towards a blanket ban or more harsh restrictions on them for the safety of the aircraft and its occupants.

We’ve done some digging and looking into the internal regulations from the Top 5 airlines leaving the UK to Europe and further afield and they have no issue with it, providing the following points are adhered to (and most of it is of course common sense!).

How to store the batteries for transport;

  • Pay special attention to ensuring that the packaging of batteries is secure and prevents short circuit (all of our cases are more than sufficient and are free with any order)
  • Protect spare batteries from ingress of liquids (this should be easy, as all liquids should be in plastic bags)
  • Ensure that any batteries travelling in a device are isolated (in other words, make sure the device is switched off and cant be accidentally turned on/activated)

The next part is specifically related to how they can be transported via air.

In your hand bagged/carry on luggage;

  • Batteries must be kept in the device, or;
  • Maximum of 4 spare batteries per person kept in original/secure packaging (max of 2 with Flybe)
  • Lithium metal batteries (Liion/Li-Ion) must not exceed a rating of 100 watt hours (i’ll come to this shortly)

In your checked baggage (hold luggage);

  • Batteries must be kept in the device and powered off.
  • No spares

Exceptions to the above are all Virgin, EasyJet and FlyBe flights where no batteries can be carried in the aircraft hold. Hand/carry on luggage only.

How to calculate Watt Hours

Almost all airlines, whether taking batteries on holiday or shipping them abroad place restrictions on batteries/cells above 100 Watt hours. To calculate watt hours, you take the mAh (millamp hour) rating of the cell, divide it by 1000, then multiply by the voltage. For the Samsung 25R, the calculation would be 2500/1000 (2.5) x 3.7, making the total watt hour rating 9.25W/h. Well under the 100W/h limit!

Please note that in the unlikely event that you are searched and the cells are discovered, it is your responsibility to be able to provide the ratings of the cell for calculation. With our compliance marking this of course isn’t an issue but if you are buying non-compliant cells elsewhere, the onus is on you as the passenger to prove the specification and output. Failure to do this will result in the airline confiscating and either destroying or charging for the storage of your batteries until your return.


Virgin Atlantic

British Airways




18650 UK has collated the information in this blog post from the Restricted Baggage and associated pages from the websites listed above and while correct at the time of writing, may be subject to change without warning or update here. Always contact your airline directly if you are unsure.

Hope this helps!

Ben – Sales Director


There isn’t really a straight answer; its very subjective and will depend on what you want it to do…

Let start with the basics

Why do we use 18650 and close relatives? 

The answer is quite simple. Energy density. Gram for gram, lithium based cells are far more powerful that anything else readily available that can be easily put in an out of a device by anyone familiar with nothing more complicated than changing the batteries in a TV remote. The other option is an integral battery but often when they fail or reach their “end of life” (normally several hundred charge cycles) the device is redundant with replacements either not available or not economically viable.

What should you look for in choosing a battery for vaping?

This is where things get a little hazy, because contrary to popular belief or what people on Facebook might tell you, there are many right answers, not just one. There are also many wrong answers.

First, put price at the bottom of your priorities and consider that you’re going to put this in front of your face/in your mouth. Is not paying an extra £1 to a reputable vendor rather than a hooky eBay shop really worth the risk?

Next, we need to look at what your needs are. You can have high discharge, or high capacity. You cant really have both. You can have a reasonable mix of the two, but any increase in discharge output (current, measured in Amps) will incur a capacity output penalty (measured in mAh). Do you want something that will hit hard all the way to empty (technically known as “low sag”) or do you need something that will get you through the day?

We’ll look at these separately below;

Discharge rate (constant current or “CDR” – Constant Discharge Rating, measured in Amps)

We stock cells that range between 1.5A and 40A output. The KeepPower 8A 18650 is a fantastic cell in its field, arguably one of the best and even though it will fit in some vape devices, it wont last more than a few seconds before something terrible happens. This is because the discharge rating is far too low to power a vape device. Its a torch/laser cell. This is where subjectivity comes in.

For regulated or mechanical devices, you need to select the right cell for the job and again, this is where its subjective and a little bit of Ohms Law knowledge is required (or you can cheat, and Google an online calculator). For the sake of simplicity, we’re not going to use pulse discharge ratings here. Just the CDR.

For example – you’re running a single 18650 mechanical device and you place a RDA with a 0.20Ohm coil(s) on top. With this “load” and a fully charged 18650 (4.2V), it will be drawing 21A from the cell. Consider a Samsung 30Q for instance; one of the top selling batteries in the industry. It’s Constant Discharge Rating is 15A. This puts you at almost double the rated discharge. It doesn’t mean its not a top performing battery, its just not right for this application. The Sony VTC5A and Vapcell VTC5D and VTC6A re-wrap however would be perfect, with ratings of 25A+

Capacity (how long the cell will last between charges, measured in mAh – Milliamp Hours)

Again, we have cells ranging from 1500mAh, to over 4000mAh. Everyone wants the highest mAh possible. Less time charging and the ability to carry less batteries is convenient, but its a trade off. You cant have a 4000mAh 30A 18650 cell (no matter how many times China put figures like that on a wrap!)

Broken down in the simplest possible way, an 8A 4000mAh cell will provide 1A of power for 4 hours. 2A for 2 hours. 4A for 1 hour. 8A for half an hour, and so on (so long as the current doesn’t exceed the maximum constant discharge rating)

The above has very little relevance in vaping, because its used in very short bursts, but you get the idea. More mAh, longer run time.

Internal Resistance

This is a mostly overlooked but actually fairly important factor. The lower the internal impedance or “resistance” of a cell, the easier it is to deliver its energy. High resistance cells will struggle to expend their energy efficiently, instead turning the pressure of not being able to discharge at the rate being requested by the device into heat. Low resistance cells are much more efficient, offer less voltage sag and this is where the “hard hit” bit comes from. Lower resistance = More instantaneous power.

Understanding Battery Codes

Our compliance markings aside, there are lots of markings on batteries. We’ll break them down to make them a little easier to understand;

  • IMR – Lithium Manganese – IMR is one of the most stable and one of the highest current producing chemistries. It has the lowest running temperature in comparable tests making it far safer than older ICR technology. Interestingly, a lot of re-wrap companies mark their batteries IMR, when they’re actually INR.


  • INR – Lithium Manganese Nickel – INR is probably the most common in vaping. It blends nickel and manganese to form the positive cathode, providing low resistance and the ability for high current output. A lot of effort is put into this chemistry by manufacturers, shown in the Samsung 25R and the LG HE2.


  • NCA – Lithium Aluminium – NCA is a much lesser used but still comparable chemistry to INR. It does away with the manganese element of the cathode in favour of aluminium. You wont get the high level discharge ability of an INR cell, but you do get a much longer run time and increase shock resistance. They’re currently being used by lots of e-bike manufacturers, and Tesla use them in their vehicles!


  • ICR – Lithium Cobalt – ICR chemistry is used for one purpose. Energy density. Unfortunately this comes at a cost and that cost is stability. It bugs me that cells with this internal chemistry are available individually to end users on eBay and Amazon because they’re of almost no use to the general public bar DIY pack repairers. The Samsung 26F for example (most often found in laptop batteries) has a wrap the same colour as the Samsung 30Q; they can be very easy to confuse. The 26F is a 5.2A cell (factory data sheet rating) which is of almost no use in vaping. Put one of these in a vape device and run it at above 20w and you’re almost guaranteed to have a bad time.


  • IFR – Lithium Phosphate – IFR (more commonly known as LiFePo4) has very specific uses and is rarely seen in vaping because of its super low energy density. There are some that can be discharged at very high rates however, often upto 30C (30x its capacity) The average capacity is about 1200 mAh, some are much lower. So for example a 30C rated IFR cell could be discharged at 30 x 1100mAh, so 33Amps! But, it wont do it for very long at all. They also have a voltage cut off of only 3.2v. Much higher than the normal 2.8v or even 2.5v of other lithium based cells.


So. Which is the best 18650 battery? The answer is easy. All of them, in their own little way. Take time to consider what you want from the cell and pick the cell most appropriate to your needs, not just what everyone on social media is shouting about!

I hope this serves to answer the question but if its left you with more than you started with, feel free to drop them to us via message or post on Facebook, below in the comments, or Email Us


Ben – Sales Director

Who are they, where did they come from and what are they doing?

We have some idea. We have scraps of information we’re piecing together from the few people who aren’t scared to offer them but we dont have everything. After-all, that’s all part of the mystery, isn’t it?

Let be clear before we start – This isn’t a sweeping shot at all businesses in these two areas. We purchase from and supply some fantastic businesses in both of these areas which is the case for the most part.  What it is, is the start of an internal industry investigation spanning close to a dozen other businesses into counterfeiting of the products we supply, the safety of past, present and future customers, and an overall look at what damages an industry, through the eyes and experiences of those who operate in it.

Welcome then, to part two of “Things that upset Ben”

Why the “The Birmingham and/or Manchester boys”?

No idea. This is just what most refer to them as. Whenever they’re mentioned, this seems to be the common nomenclature. Its not just these two locations though. Bolton and a few others are fast moving up the ranks but the first two are the most common.

Who are they?

Wholesalers, mostly. Down little alleyways, in basements, houses, market stalls, secret underground shopping malls. These aren’t your average stand up business with flashy websites and a huge online following of happy customers. Often you have to know who to ask, where and when. They only supply a small number of people who then filter the products outward. They import almost anything from home-wares to consumer electronics, cosmetics to furniture. Anything that China produces and they can make money from. There’s nothing wrong with that though. You could argue that for the most part, everyone in the vape/e-cigarette industry is doing the same thing, us included.

So whats the problem?

Counterfeiting. VAT fraud (see my previous blog post) and according to some their activities even extend to organised crime like money laundering and drug trafficking. We cant comment on the last two and I’ve no interest or time to go digging into it. But we can look at the first two because they’re both directly relevant to and impacting everyone who operates in this industry.

What do we have?

We have some names; personal and business. We have some inside information on the way they conduct their business and who with, where and when. You name it, its happening. So lets just look at the two things above.

First up, counterfeiting.

Its covers everything but we’re focusing on cells here. We’re sent dozens of cells for testing in addition to the database of information we’ve accumulated from test orders with businesses across the UK who’ve been highlighted as potentially selling counterfeit cells. At the moment we cant supply the information we’ve gathered because it would damage current investigations but we work closely with authorities and any useful information is passed on. This includes the products themselves, the results of our tests and any other supporting information/documents.

Its not difficult to understand the “why”. Its easy to compete in a highly competitive industry if you’re selling a product at 20% less that everyone else. You can buy Sony VTC5A wholesale in the UK for circa £3, or Samsung 25R for around £1.50 and of course, there’s no VAT. At the time of writing, you cant get legitimate Sony VTC5A cells that cheap. Likewise, £1.50 for a Samsung 25R is considerably less than what even we pay and we can turn over upwards of 30-40,000 of them each month when supply is good. Why are they so cheap? Because the VTC5A were old stock VTC4, and the Samsung 25R we’re actually almost identical in performance to a 26F and you get what you pay for. Counterfeits.

Throwing the big “V”.

Value. Added. TAX. Value? Debatable. Added? Always. Tax. We’re (mostly) all used to that aren’t we? We all hate it for different reasons but you have to pay it or you go to prison. Some have even spent some time being looked after at Her Majesty’s Pleasure that ironically, they didn’t pay for. If you know the right names to Google you can even view the local newspaper articles online. But if you set up the business in a family members name and go right back to what you were doing, that’s all good right? (/sarcasm)

Another way of grabbing business and extra profit is not charging or paying VAT, or worse, charging it to appear legitimate when not actually VAT registered. VAT law in the UK can be complicated in areas but there are plenty of ways it can be quickly and easily set up and any business accountant can walk you through it with ease. The government says “Tax doesnt have to be taxing”, and it really isn’t. Its as easy to bend as it is to comply.

So how are they doing it? (This is not a how to guide!) – Some are very un-creative. They just dont charge VAT despite being well over the threshold at which they should and when HMRC come knocking, they close the business. Some take advantage of the “Flat rate” VAT scheme whereby they pay a far lower rate of VAT but in return, cant reclaim VAT on purchases and when they hit the threshold where they should convert to full rate (20%) VAT,  they close the business and open under a different name. This was easier before the GDPR. They can no longer transfer customer data meaning they lose everything. (that said, if they’ll skirt VAT, i cant see them complying with that either).

Then there’s the really creative ones. They take a bit of skill and some foreign help. What if i told you its possible (with the right connections), to import a container of stuff, pay the VAT and import duty, empty it, put all the boxes back (along with some junk to make weight) and then ship it back as “goods not required” or “Faulty”, have it signed for the other side, then claim the VAT amount back? I honestly nearly fell off my chair and almost sent my mouthful of coffee into the face of my contact when i heard that for the first time. This is actually happening, in our industry, probably as i write. I didn’t even know what to say!


Crazy isn’t it? The lengths people will go to just to get one up on a competitor and one over on their customers. Instead of focusing on top quality customer service, keeping ahead of trends and having the right products at the right time and enjoying the healthy competition it creates, they just take a giant metaphorical crap all over our industry in the name of a few extra quid while putting all of our safety and livelihoods on the line.

If you have any information on the source of counterfeit cells, please let us know in complete confidence in an email to hello@18650.uk We keep records of which cells turn up where in order to trace them backwards. If you have any information about VAT or any other type of business fraud, you can report it completely anonymously here – www.gov.uk/report-vat-fraud

That’s all, for now… Let us know what you think below!

Ben – Sales Director

18650 UK








No really, it is..

What am i talking about?

“Do u do cash deals?”. “Can i not pay the VAT?”. “Can i just like maybe send it to ur personal PayPal or bank or summink”?

The first time it happened about a year ago, it was quite funny. I’ve never had it in any other industry before and of all the verticals we supply, its only ever the vape industry that ask these questions. Businesses more than end users mostly. With the frequency of occurrences hitting monthly and occasionally weekly now, i think its time to address it.

Firstly, its both completely immoral but also obviously (you would think..) ILLEGAL

We are a full rate VAT registered business. We pay VAT, we charge VAT. Its that simple. Operating small to medium businesses in the UK has only got more tricky over the last decade and why should anyone get a leg up in this way? If we’re not all playing the same game by the same rules, no-one can actually win and lets be honest, if you’re going to attempt commit fraud (which is exactly what it is) we dont want to be a part of it, and its probably best not to do it against the Government. They do make the rules after-all…

It makes a mockery of the industry.

Why are we only seeing this from businesses in the vape industry? I’m sure it happens in many other industries, but this is our experience. The vape/e-cigarette industry is experiencing one of the fastest growth rates of any industry in the UK and as a result, competition is fierce. Is that an excuse to break the law to beat the shop down the road, or the online business you think is taking your customers? Surely not?! For an industry that got away with so much before the introduction of the TPD and is still enjoying a lot more freedom than our friends are getting from the FDA in the USA, why bring unnecessary negative attention to an industry which is already being looked at for new taxation classes and regulation?

What can we all do about it? 

Not a lot really. We politely decline all requests to not pay VAT or put cash in our own PayPal accounts. Some will just accept it and order anyway, others never come back and some even get quite angry about it. People like this damage industries. By not paying their way like everyone else they are able to undercut law abiding businesses, driving a price war and racing to the bottom where in an already “pence margin” industry businesses will fold, everyone loses the game and while some lose everything else too, these people will just move on to destroy another industry. They’re here for the good time, not a long time. We might drink like that after some weeks, but we dont do business the same way!

If you’re reading this and this is how you operate; please don’t ask us do it. It”ll be awkward for the both of us.

Has this happened to you? How did you deal with it? Let us know below, on our Facebook page or drop us an email to hello@18650.UK

Stay tuned for my next blog of “Things that upset Ben – The mythical Birmingham and Manchester boys”

Ben – Sales Director



You might remember that we recently ran a poll to tackle some of the questions we would love to ask every customer who uses the site but unfortunately, its just not possible.

That said, we had a fantastic response from customers and non-customers both on the survey and via email and i thought it might be interesting to share our thought process behind the questions and some of the results with the public.

Some of the questions are irrelevant to anyone but us so if you filled in the survey (thank you to all 1500+ of you, we hoped you enjoyed the little surprise at the end!) and you’re wondering why some of the questions aren’t here, that’s why!

So. Question time. Its worth noting that this poll was completely anonymous, so we can only base opinions on the answers given…

First up, we asked where people had heard of us. We had a feeling that Facebook was probably the biggest driver of traffic for us. We were right, with 61% of you joining us from our Facebook page (www.facebook.com/18650UK) Almost 20% of you had come from Planet of the Vapes (www.planetofthevapes.co.uk) which is nice to see given the Facebook age is slowing killing forums which before big socials, were the primary source of information on just about anything!

How many cells people buy at a time is difficult to track in our software, so we thought this was relevant. Mostly so we can tailor our offers to customers. The 2-5 bracket took the win as you can see below

Question 4 tackled the long running debate between the LG HG2, Sony VTC6 and Samsung 30Q, given how similar these cells are. We dropped the ball on this one, not providing a “not applicable” option for those who dont use them. This may have skewed the results as it was a mandatory question but the results were interesting. (Personally, i like the colour green..)

Next we looked specifically at customers who purchase cells for vaping. We were keen to see what devices people were using the cells for and the results confirmed what we expected. Most people are regulated device users, with another chunk who use regulated primarily with a dabble in mechanical, me included.

Immediately following this, we asked vapers which was more important to them; Capacity (mAh) or discharge rate (Amps). The results were close, with a slight preference on capacity. I have to admit, i was a little disheartened to see this result. Not having to faff about swapping batteries out or carrying them would be fantastic, but when you’re placing a device next to your face, i really hoped to see more people pick the safety option of discharge rate over the convenience of capacity here.

Question 8 covered another debated subject. Who is the biggest charger manufacturer? This one did surprise me. I gave 4 options based on the largest numbers of them on other mediums (eBay, Amazon, etc. Unfortunately a hotbed for low priced counterfeits). Nitecore, XTAR, Efest (LUC) or “Another brand not listed”. Nitecore have been around a long time and despite the number of conspiracies and counterfeits that have trickled through over the years they came out on top, by a considerable margin. Personally, i prefer XTAR but purely on aesthetics, and because my VP4 Plus Dragon has an internal resistance check function that i dont need to leave my desk to use. Both are fantastic devices and deserve their share of the market but given the number of XTAR chargers sold by our closest competitor, the result was a pleasant surprise. Equally, the number of “others” taking only 4% i think really shows who the top players are here in the UK

The next constantly contested subject, the peoples favourite OEM cell manufacturer. We kept this simple, a shootout between Sony, Samsung and LG. This is one of a few questions i want to explore a little deeper in the future to see if its performance, price or a bit of both but the results are clear. With very little new development in cells usable in vaping from LG lately, Sony and Samsung are leading the way with new options in the form the VTC6A and VTC5D, and the 20S, 24S, 25S, 30T and 40T from Samsung.

With the rise of Chinese re-brand companies, we wanted to get peoples thoughts on the best of them. Vapcell, with their recent ability to source strong, new to the market cells and rate them in line with their true performance has given them the edge over their competitors. Hopefully, we’ll be seeing all businesses who re-wrap OEM cells do the same. Afterall, at the very least i morally wrong to sell someone something that doesn’t perform like it says on the tin. At the very worst, its unbelievably dangerous.

Whats this has shown us however, is that we missed something big here. Almost as many people who picked Vapcell, picked someone not listed. This is another question we have clear reason to revisit at some point. Was everyone voting that option for one company, or lots? We need to know!

Our full compliance with UK and EU legislation is what sets us apart from our competitors. Out of the literally hundreds of companies in the UK selling these cells, we are one of only 3 companies who are fully EU/UK legislation compliant. Unless you are buying cells from us or the two others (or a business we supply to as a wholesale customer), you are buying products that shouldn’t be on the market. We asked how much this matters to our customers. We’ll let the results do the talking here.

Before this next question, we asked where people got their cells from before using 18650 UK. The winner was the same, and its unsurprising. One of the only other compliant companies in the UK with a fantastic following and a business we have a great relationship with so it was great to see them come out on top with our customers who needed something we didn’t have at the time they needed it. We work hard to keep our stock level higher than demand but just with your favourite supermarket, occasionally we get caught short and its good to see that for the most part, if we dont have something you’re looking toward the only two other compliant businesses in the UK.


You might notice I’ve removed two company names from the above list. At 18650 UK we love competition, but not with companies who aren’t interested in playing the game by the same rules and for this reason, I’m not able to show their name here.

Those buying from “Another UK based business”, could well be vape shops or online stores we or our compliant competitors supply to. They could however, be other UK competitors who aren’t compliant. Its impossible to tell unfortunately.

Those buying from Alibaba, Aliexpress and similar – almost guaranteed non-compliant product and another hotbed for counterfeit cells. If you’re reading this. Please. Don’t risk it. It’s not worth the potential harm to your wallet or health.

Lastly, if you want to help stamp out counterfeit and poor quality cells,  unsafe stated battery ratings and contribute to the wealth of testing data and information aimed at making vaping safer, please take a moment to look at the following page from Mooch – Mooch’s Patreon Page

If you haven’t heard of him, Mooch has a background in the very same work he has tirelessly carried out for the vaping industry for little to no return for many years, despite investing tens of thousands of dollars in equipment. For many, he is the first source of information on selecting the right cell for their purpose and his work in the industry from testing hundreds of cells and devices to actively hounding Chinese manufacturers has contributed to a huge number of industry changes.

He’s keen to quit his day job and work for you, full time. A couple of dollars/pounds a month makes a big difference. If everyone we’ve ever supplied to pledged just £2, we alone could probably keep him charged for a whole year!

What do you think? Couple of surprises? Us too! Let us know what you think on our Facebook page or drop us a line – hello@18650.UK.

Thanks again to everyone who got involved. Its been… interesting..!


Sales Director – 18650UK


*This blog post is taken from a mailshot sent to all past and present wholesale customers today (12th April 2018) but will ultimately affect and is relevant to all 18650UK customers, any other business involved in the purchase and sale of these batteries in the UK/EU. Its time to start listening…

Trading Standards are on their way into stores…

Are you ready? Are you compliant?

At the end of 2017, Ben our Sales Director met for the first time with the UK government representatives for the EU Battery Directive to discuss the use of 18650 and other cells in the vaping industry, the law surrounding the supply of them in the UK and EU and what is and isn’t being done in the industry to ensure total compliance and most importantly, customer safety. If you are selling these batteries to your customers, it is your responsibility to ensure you are doing so legally. Of course, at 18650UK we do this for you at no cost further than the cell itself.

Why has it taken this long? Simply, because writers of the EU Battery Directive and Trading Standards weren’t fully aware of the use of these cells in vaping. And since they’re designed for power packs, electric vehicles etc, they are NOT compliant with the regulations “out of the box”. Having spent months in communication, they’re now aware of exactly how they’re being used in the vaping industry and are ready to support people on the route to full compliance with plans to update the directives to cover them more specifically.


Do your batteries arrive like this? – This is not compliant. Not only are the stickers removable (regulations state the markings must be totally indelible), they dont have the necessary information on them. The polarity and WEEE bin symbol are missing, as is the chemistry marker. Want to know more? To start, the only reason they come in these boxes is to satisfy Chinese air export law; they have to be individually boxed. Nothing to do with retail convenience. Tens of thousands are poured into huge bins, then pulled out and individually boxed. Prime opportunity to lob a few boxes of counterfeits in the mix and boost already very slim margins too…

Importing from China? – Almost all of the cells/batteries we wholesale/distribute are manufactured in the Far East. Did you know that if you import direct from China, you are classed as a “Producer” and have much bigger legal responsibilities than just selling them? If you are the first business to place the cells on the market in the EU, you are responsible for having the batteries batch tested. You will also need to be able supply proof. With thousands of batch codes mixed together because of the above process, you can imagine the cost… This is why our batteries come by sea. Batch testing is much quicker, easier and cheaper when you have 20,000 of the same batch in their original factory boxes! You also need to register with the relevant government body, a WEEE scheme and have specific insurance to cover these products. (Picture is of a recycling plant. The 3rd party re-boxing plants look similar. The batteries just have wraps on…)

The law was already broken before we got here – It was the same for us too. When we started out, we were unaware of just how in depth the regulations were. But the old saying “ignorance isn’t a valid defence” is very true here. Being unaware of your responsibilities wont stop Trading Standards removing your batteries from premises and its already happening. We’ve seen rumblings on socials and have even had a few companies come to us having suffered the same fate. Buying from 18650.UK saves you the worry. Every cell is fully compliant.

What can you do about it? Challenge your suppliers. If they’re selling you non-compliant batteries, you could agree they dont have your best interests at heart. It would take a very serious customer service commitment to offer you a total order replacement if Trading Standards remove our cells from your store. Would they do it? We do. Having had our cell markings approved, Trading Standards are a help, not a hinderance. We’re that confident, if there’s ever an issue, we’ll just replace them, hassle free. We’ve never had to do it, and we dont expect to…

Picture of Battery Directive Sony VTC5A 18650


What do i look for? The minimum standards for cell compliance are the following; The RoHS bin symbol, Capacity, Chemistry and Polarity. As you can see, these are all present in our markings (polarity on the reverse on this 1st generation print. They are now all on the same side) which are done in house on our soft conveyor fed TIJ system. This is from the same manufacturer  of equipment used by LG for the marking of their cells. This machinery uses a thermal ink, making it almost impossible to remove without harsh chemicals. It satisfies what the normal stickers do not; the markings must be indelible. On the box doesn’t count either. It also safely processes several thousand cells per hour, meaning no delay in getting them to you.

What are the other numbers? – We’re building an internal database of cells sold by us and have done since 4th January 2018. Every cell that leaves us (with the exception of those going to the accumulator/EV market) is given a unique serial number, making up most of the second line. This VTC5A pictured displays YA 003 00001. Y is 2018, D is January, 003 is the date, 00001 is the unique cell number from this batch; in this instance, the first. This format allows us to accurately trace any cell sold by us internally and externally. We hope that this will prevent counterfeiting of our markings, since we hold a record of exactly who we sold each wholesale cell to. (Cells sold on our retail website also have SOLD BY 18650.UK on them. We can place your company name here on wholesale orders and at no cost!

Need more information? –  This isn’t an exhaustive “how to” guide. There are many more things to consider, which we cover for all of our customers. Full details of the requirements and responsibilities for selling batteries in the UK including all of the above can be found on the gov.uk website by clicking here

As always, if you need anything further, dont hesitate to get in touch.

Ben – Sales Director – 18650UK