#vapcell

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

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.

Sources;

Virgin Atlantic

British Airways

FlyBe

Jet2

EasyJet

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!

It’s a question often asked by people who have little to no experience with 18650 batteries and look at them from an appearance aspect only, so lets start there; Size matters Cylindrical lithium batteries are named by their size. A bare “unprotected” and “flat top” 18650 battery will always be 18mm in diameter (width) and are 65mm long (give or take a little manufacturing tolerance). AA batteries on the other-hand are 13.5-14.5mm in diameter, and 49-51mm long. This tolerance is much wider, largely because AA batteries are normally fitted into spring loaded compartments and a millimetre or two difference is of no consequence.

Voltage The most common nominal voltage for almost every NiMh or NiCD AA battery is 1.2V-1.5v. 18650 batteries have a nominal voltage of 3.6V, so this means you would need 3 AA batteries in series configuration (attached end to end) to get the same voltage as just one 18650.

Capacity, current and “Energy density” The highest capacity AA batteries on the market right now are made by Ansmann with 2850mAh but this is the very top end of rechargeable AA form factor cells. For the most part, 2500mAh is more readily available and considerably cheaper and we have a fantastic range of Eneloop products in this top end category. The highest current that can be drawn from any AA battery however, is only a few amps. Some 18650 batteries can be discharged at rates more than 10 times the ability of an AA option. The Sony VTC5A 18650 battery for example can be discharged at 25A continuously.

The biggest reason to use 18650 over AA is Energy Density. We won’t get too far into it here, but far enough to demonstrate some easy figures. Energy density is the measure of how much energy is contained within a battery or cell measured in Watt hours. Calculating the Watt hours in a battery is very simple. Take the mAh rating, multiply it by the nominal voltage, then divide by 1000.

For example, a normal Duracell Alkaline battery has around 1500mAh. Its nominal voltage is 1.5V. This means that (1500*1.5)/1000 = 2.25Wh. Not a lot at all

An LG MJ1 has 3500mAh and a nominal voltage of 3.6V. (3500*3.6)/1000 = 12.6Wh

That’s a big difference and is what (appearance and small increase in size aside) sets 18650 apart from AA batteries.

Conclusion Ultimately, the best battery for the job is decided on by the manufacturer of the product and its rare that they get this wrong. To use 18650 batteries in a TV remote is overkill and would make them much larger. To use AA batteries for vaping doesn’t work because they don’t have the required current output ability or energy density. What does remain however is that they are two very different products, each with their own set purpose, characteristics and applications. If you’re ever in doubt about what to use in your device, you should always contact the manufacturer of the product or a reputable battery retailer for advice.

How did it do?

Very well.

The initial 10A discharge maintained a strong 2500mAh. Not quite enough for me to call it a true 3000mAh cell, but Sony rate their cells on discharges at half of this, and its still 200mAh above what is widely recognised for the VTC5A at this load.

At 15A we start to see cell temperature rise to 37’c. This is still unbelievably low. So low that i started questioning the ordinarily well respected test equipment we have (more on that later).

At 20A temperature rose to 48.8’C and the cell maintained 2400mAh. This is still a very low temperature for a 20A continuous discharge.

At 25A temperature rose to 61.8’C, and managed 2200mAh. This is still strong going given we’re now at the rating given by Vapcell.

At 30A, temperature seconds before the end of test was 74.5’C. This is pretty hot, but still under the 80’C maximum working temperature limit Sony set for all of their cells. It also still managed to provide 2000mAh. Vapcell may have been a little conservative with their rating, which is always far better than being wildly (and dangerously) optimistic.

A further run at 35A (not shown) just for the sake of science gave a reading of 86.8’C. This is over Sony’s recommendations, and over that which would be safe in individual cell use outside of a battery pack that doesn’t have an integrated cooling system.

The thing that sticks out for me against the VTC5A and the VTC6 which people are hoping this will be a hybrid of, is the sag. Its considerably more than both of them. I’m investigating if some of this is in our equipment although previous tests against others peoples results have been near identical.  I hope to do a shootout between all 3 soon.

Test equipment

We use a West Mountain Radio Computer Battery Analyser IV Pro. Its a small but very capable unit, and until recently was being used by a very well known cell tester and still in use with other cell vendors. Cost vs performance is fantastic and not out of the scope of companies selling a reasonably large number of cells to help with cell testing/verification. We dont normally release this stuff but as this is a brand new cell with barely any available information, it felt like the right thing to do.

In the interest of transparency, i got a reading of just 15’C @ 10A and 24’C @ 15A on the initial tests. This was obviously far too low to be correct, it was traced to a faulty temperature sensor on the unit. Its a little magnetic sensor that sends a temperature signature to the software. Speaking to another cell vendor and user of this system this appears to be a common thing, so to rule out the errors and get even more accurate figures i’ve switched to a standalone laser/infra red temperature sensor. All readings above were taken with this new, fully calibrated equipment.

That’s all. If you have any questions or need any further information, drop us a message or send us an email

NiCad (Nickel-Cadmium) and NiMH (Nickel-Metal Hydride) are two very different types of batteries. Both types must be handled differently from one another in regards to charging and discharging procedures and philosophies.

In general, NiMH batteries cannot handle the high rate of charges or discharges (typically over 1.5-2 amps) that NiCad batteries can. Many modelers use high rate, peak detection or time-based chargers to charge NiCad batteries. Such chargers are NOT recommended for NiMH batteries (unless otherwise specified in the charger or battery literature) as they can cause permanent damage to the NiMH cells. Also, NiMH batteries will not perform well in high rate discharge applications, typically providing only a small fraction of the rated capacity in these instances.

NiMH batteries also have approximately twice the self-discharge rate of NiCad batteries when in an used state. For example, when your radio is off, a 1650mah NiMH battery can discharge itself nearly twice as quickly as a NiCad battery, typically within one week. Therefore, you must charge your NiMH batteries the night before each use.

When handled correctly though, NiMH batteries can be very beneficial, providing much longer run times than comparably sized and weighted NiCad batteries.