So, we will be carrying a new line of mechanical mods soon, but before we sell them at the shop, let's talk about proper usage and safety..
This article is intended for new vapers who want to get hold of their first mechanical mod. The first thing we must distinguish is the difference between a mechanical mod and an electronic Personal Vaporizer (electronic PV).
A good and properly designed electronic PV has a built-in chip in the unit itself that acts as a protection circuit, it prevents things we want to avoid while using any unit and these usually includes over-discharge and short circuit.
Because of the built-in safety features, electronic PVs are inherently safer than fully mechanical mods. Some popular electronic PVs are Provari, Lavatube, eGo and iTaste.
The problem with mechanical mod, however, is that obviously it does not have a chip that can monitor things like short circuit and over-discharge. Short circuit and over-discharge, without getting too technical, basically make the battery unstable to a point that it may overheat and catch flames.
And this is the reason why we are posting this article up - so that we can show you what you can do to compensate for the mechanical mod's lack of the native circuit protection.
For some of these, it is implied that you get yourself a multi-meter of some sort. In fact, if you choose to own a mechanical mod, you should also get a decent multi-meter.
Let us go into each in detail.
Unlike your Provari or Lavatube, a fully mechanical mod will still fire even when a short occurs on the atomizer. A short-circuit technically means zero or close to zero resistance (ohms), but most electronic PVs won't allow anything lower than 1.5ohms. This is to ensure the batteries are not stressed specially if they have lower C ratings.
If you are using a new atomizer, make sure you check your resistance first before screwing it on your mechanical mods.
If you are using a rebuildable atomizer, do not let the ohms go too low as some batteries may become very stressed with lower resistance. When starting out, build them at a standard resistance around 2.4 to 3.0 ohms just to be safe.
Short doesn't always occur in the atomizer, test the unit itself as well. To do this with a multi-meter, take out your battery, with one probe touch the positive pin of the mod and another on the body. If the meter shows any kind of resistance, it means the current is flowing and you have a short somewhere.
When testing for resistance using a multi-meter, note that the multi-meter also carries it's own resistance or lead resistance.
In cheaper multi-meters, we have seen this lead resistance go as high as 0.6ohms. Touching both probes together will usually display how much lead resistance the meter has. Subtract this from what is displayed on the meter when testing your atomizers to get the atomizer's real resistance.
So if your atomizer reads 2.0ohms, it may actually be just 1.4ohms if your lead resistance is 0.6ohms.
Another suspected cause of batteries being damaged or even catching fire (thermal runaway) is when it continues to discharge way past its discharge threshold. Meaning; using it way past empty.
A Li-ion battery typically holds a capacity of 4.2 volts at 100% charge. As the battery is used, this voltage drops.
Depending on quality and manufacturer, typically your batteries can be safely used until the voltage drops to 3.6 to 3.3 volts (or even lower on really superb ones).
On the safe side, when a battery reaches 3.6 volts, just assume it is empty (as it might as well be), stop using the battery and recharge it as soon as possible.
If you are unfamiliar with your batteries, use your meter to test your batteries often to determine how much usage time you typically need to get from 4.2 to 3.6 volts. This will help you estimate how much is left when you don't have your meter with you.
Just note that as the battery ages, the time to reach empty will decrease, and this is due to the internal resistance building up (We will talk about how to determine this in another article about internal resistance).
Unless you really know what you are doing, simply do not do it.
Stacking batteries means putting one battery on top of another in series so they produce a higher voltage. It also adds much more stress to each of the batteries.
Two "stacking" batteries is not recommended
Not all batteries are designed to be stacked. Stacking will stress both batteries much more than when the same atomizer is used in a one-cell configuration.
Both your batteries must be capable of very high C ratings(which we may discuss in another article) and unfortunately, most batteries are not. If you really want to stack batteries, make sure your batteries are designed to do so.
Another problem with stacking batteries is, again, over-discharge. One battery may already be fully charged while the other half full. Sooner or latter, one will ultimately over-discharge and cause some problems.
Even on a new pair of batteries, there is a chance that in time one of these batteries "gets old quicker" which will make it empty quicker than the other. This often happens even in "manufacturer pairs".
If you have no choice, such as you have a mechanical mod that only accept stacked batteries, you can use a spacer (dummy battery) or purchase the best quality batteries that are designed to be stacked. Use atomizers with a resistance that will not stress your setup. And always check the health of your batteries regularly.
If you really need a higher voltage than what a single cell can give, consider a variable voltage electronic PV or a kick device for your mechanical mod.
Other than over-using your unit beyond empty, another cause of over-discharge and battery stress is accidentally firing your unit for prolonged periods of time. Usually this happens accidentaly.
Electronic PVs like the provari, lavatube and eGo usually have an automatic 10-15 second cutoff to prevent this as well as manual "off" mechanisms where you can turn the units completely off.
Some mechanical mods may have lockable firing mechanisms that functions as an "off" mechanism. But not all do.
If your mechanical mod has this feature, use it whenever you store your mods in your bag or even in its case. This will prevent it from firing.
If your unit does not, then make sure to remove the atomizer and make sure nothing can short the positive terminal (the pin where your atomizer connects to). Placing your unit in a small pouch bag before placing it in your case can help prevent this.
In our market today, there are many kinds of batteries that can be used in a mechanical mod.
Two most popular battery types used in mods are ICR (LiCo02) and IMR(LiMn) / IMR hybrids. Both of these are lithium-ion (Li-ion) batteries.
In terms of safety the difference between the two (ICR and IMR) is the chemical composition in these batteries. ICR can catch fire at a faster rate than IMRs because they are simply more combustible. ICR are also generally known to stress more easily than IMR.
There are two types of ICR batteries, protected and unprotected. Never use unprotected ICR in any mechanical mod as it does not have any safety mechanism in them.
Protected ICR batteries have a basic layer of protection that prevents your batteries from shorts and over discharge problems. Protected ICR with a C rating of 2 amps or more can be used in mechanical mods.
IMRs however, has a more stabler chemistry, and won't likely to catch fire or explode as easily as an ICR can. They do not require protection, and often sold without it. These are also suitable for mechanical mods.
You may ask, what is better an IMR battery or an protected ICR battery?
The general consensus in the vaping community is that when in doubt, IMR is better for mechanical mods. The reasoning is, although IMR has no protection circuit, by nature of their chemical composition, they are safer than ICR with a protection circuit. Protected ICR batteries have a history of their protection system failing, specially with the cheaper ones. In fact, we have read more incidents of cheaper protected ICR batteries venting flames than IMRs.
An analogy to this is that a protected ICR is like a gun with the safety switch turned on, and an IMR is a gun someone filled with rubber bullets. Both guns can hurt but one is more hazardous.
The outside of the battery is always negative, therefore your mod's case should also be negative.
In most mods, the negative portion of your battery is at the bottom of the mod to make the entire tube negative.
The reason for this is that if your battery wrapper gets damaged, and it touches the metal tube, your tube will be negative no matter how you positioned your battery. No short will occur.
However, if your tube is positive, and your battery wrapper gets damaged, you will have a short.
It typically should not go beyond 4.2 volts, although many brands have a +/- .05v in their specifications allowing them to go up to 4.25volts . If it goes beyond what is specified, consider changing the battery, the charger or both. An over charged battery should be considered unstable.
To prolong battery life, charge your batteries at 4.1volts ratther than fully charging them.
Also, never try to recharge a battery that has been severly discharged. A severly discharged battery may develop an internal short.
When you follow the rules already mentioned, you should be fine.
But even the most vigilant of us can and do make mistakes. Even if we follow all the rules, there are just some things we cannot avoid such as accidents.
When this happens, it is good to have a unit with some sort of safety mechanism in place.
One of the biggest problems with a battery experiencing thermal runaway (which may be caused by shorts, stress or over-discharge) is that things inside the battery expands at a rapid rate.
A mod without vent holes is a sealed container that may crack, shatter, or break causing harm to you and others simply because the pressure inside the mod has nowhere to go.
A mechanical mod with suitable vent holes can prevent this pressure from building up and it can release the rapidly expanding gases before it even builds up to dangerous levels.
Think of a mod without vent holes as a balloon, when you blow to much air, eventually it will explode.
A balloon with large enough holes however, will just release the pressure no matter how much you blow into it.
Now that we have covered the fundamentals, these may feel like a lot to take in. Eventually these will be second nature to you. So have a great day and enjoy your mechanical mod!!!