Mechanical Mod Safety

Safety tips mechanical e-cig mods
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Much of the safety advice in the mods portion of “The Complete Guide to E-Cig Safety” series so far is mainly a significant concern if you’re using a mechanical mod. The benefit of electronically-controlled options (variable voltage/variable wattage mods), particularly for vapers who prefer not to get too technical, is that the protections built in to systems like the iTaste, ProVari and Lavatube drastically minimize the chance of anything going wrong. If you try to do something dangerous or if your battery needs a charge, the device will let you know about it and forcibly prevent you from taking risky action.

With mechanical e-cig mods, it’s all down to you. Don’t worry, though, if you follow the advice from earlier in this guide, you will continue to vape safely! In the hands of someone with basic battery safety knowledge, a mechanical mod is by no means dangerous, but there are extra steps you can take to protect yourself against potential mistakes.

Key Points

  • Only use high quality batteries (protected ICRs, or preferably, an IMR safer chemistry option) and chargers (an intelligent charger is ideal) if you have a mechanical e-cig mod.
  • Get a safety fuse such as the “2 Cents for Safety” to protect mechanical mods against battery shorts.
  • Use a multimeter to check atomizer resistance, ensure that the unit itself (without battery) doesn’t have resistance (although you may read the “lead resistance” from the meter itself) and to monitor the voltage (and therefore the charge state) of your batteries.
  • Charge your batteries when the voltage drops to 3.6 V – some batteries can be discharged lower but this is a safe guideline.  
  • Ensure the battery is inserted with the correct polarity, and use a locking mechanism for the fire button when available.
Nick Green GrimmGreen expert opinion

You always want to know what your batteries are capable of, and what you are asking them do to.  High quality, high drain batteries WILL cost more.  Without an ohm reader, or multi-meter you won't know the “math” of what you are doing.  It's crucial to know three things.  Your resistance, the AMP limit of the battery and how many amps the coil is asking from the battery. – Nick “GrimmGreen” Green (

Steve K expert opinion

It's a good idea to have a multimeter and test the batteries' output after each charge.  If you're using mechanical devices, it's not just a good idea, it's absolutely necessary for safety. – Steve K (Steve K’s Vaping World)

Phil Busardo expert opinion

BUY A MULTIMETER!  Or at least some device that will allow you to check the resistance of what you're about to attach to your mech. Why? A regulated device will sense a low resistance load or a short and it will prevent the device from firing. A mechanical has no brain, it depends on yours. So it will happily try to fire anything you screw onto it, including a dead short which could lead to a catastrophic battery failure. If you feel you battery or switch getting hot.  There is a problem that needs to be resolved. – Phil Busardo (

Spend More on Chargers and Batteries for Mechanical Mods

In the absence of electronic PV-like safety features, the previous advice regarding buying quality components is all the more important with mechanical mods.

Safer chemistry (IMR) batteries (with a large maximum continuous amp draw) reduce your chances of a catastrophe in the event of a shorted atomizer, and even if you choose not to go safer chemistry, never use an ICR (lithium-cobalt) battery which is unprotected in a mechanical mod (protected batteries have a mechanism to protect against shorts and over-discharge, but the “safer” nature of safer chemistry options mean this isn’t required for IMRs).

In addition, a high-quality intelligent charger protects you against overcharging of batteries. There is no need to cut costs in this department; even the most tech-savvy vapers make mistakes every so often.

Get a Safety Fuse for Your Mechanical Mod!

2 Cents for Safety Fuse mechanical mods

To that end, it is definitely recommended that you get a safety fuse for your mechanical mod. Phil Busardo (from recommends the Two Cents for Safety fuse, which you can pick up for around $6 and will shut down your battery if it senses a short.

It’s extremely unlikely you’ll ever trip the fuse (particularly if you follow the advice given in this guide so far), but if you do, it’s single-use and so will need to be replaced. At such a low price per unit, it’s prudent to get a couple so you’ll be covered in case you trip the one you’re using. It’s a precaution you shouldn’t need, but the small expense is definitively preferable to a battery-turned-flamethrower situation.

Mechanical Mods and Multimeters

e-cig mod multimeter

If you go mechanical, you definitely need a multimeter. Vaping on something without significant in-built protection and likely topping it off with a self-made coil presents too many potential issues to go on unchecked. Check the resistance of your coil regularly, as described in the previous post in the series, but with a mechanical mod you also need to remain aware of your battery’s current voltage.

When fully charged, most lithium-ion batteries offer 4.2 V, but this drops as the charge level depletes. This wouldn’t be an issue if it weren’t for the stress placed on batteries by over-discharging. Higher-quality batteries may be safe to use even lower, but when it drops to around 3.6 V, it’s time to recharge it and switch to another battery if you want to continue vaping. In many cases you can go down as low as 3.3 V, but it’s safer to charge sooner rather than later (plus, vapor production will drop notably anyway). To guard against overcharging, it’s also prudent to only charge your battery up to 4.1 V. A battery charged to over 4.2 V will have a shortened lifespan and may become unstable, especially if it’s far over 4.2 V.

It’s also a good idea to test your mod itself with your multimeter. This is because a short could actually develop in the unit, and can be checked for easily. Remove your battery and end cap before testing this, and touch the positive probe to the positive pin of the mod (the top connector for your atomizer) and the negative probe to the outer body. Remembering that the multimeter has a lead resistance (displayed by touching the two probes together), you should only see this reading when you test your mod. If it’s different, there is a problem with your mod and you shouldn’t use it.

Battery Polarity for Mods and Reminders From Earlier

The negative end of the battery always sits at the bottom of your e-cigarette mod, and this ensures that the body itself is also negative. Because the outer casing of a battery is negatively charged, this prevents a short circuit if the non-conductive cover around the outside of it becomes damaged. If you’d inverted your battery, a short would occur in the event of a damaged battery cover, and you’d be opening yourself up to all of the associated risks.

Remember from earlier in the series that if there is an off switch or a lock function for the firing button, you should use it. Accidental activation for prolonged periods of time stresses the battery, and mechanical mods don’t have the 10-second cut off you get on many electronically-monitored devices.

Finally, vent holes are absolutely essential for mechanical mods, so don’t use one that doesn’t have them. It can turn a failure involving venting gas and flames into a pipe-bomb like scenario by allowing pressure to build.


Mechanical mods aren’t dangerous, they just have more potential to be dangerous than any other mod or beginner-level e-cig if you don’t know what you’re doing. It’s easy to stay safe with a mech mod, but don’t rush ahead if you’re happy vaping a VV/VW mod or an eGo; wait until you’re confident with the technology and safety aspects before giving mechanical a try.

The Complete Guide to E-Cig Safety

Part One: Beginner E-Cigs Safety

1. Safe Use of Beginner E-Cigs
2. A Guide to Safe Charging
3. Carrying Your E-Cig Safely
4. Cartomizer Safety
5. Vaping and Driving

Part Two: E-Liquid Safety

6. Basic E-Liquid Safety
7. Allergies, Conditions and E-Liquid
8. Safe Nicotine Consumption for Vapers
9. Steeping E-Liquids Safely
10. Do E-Liquids Expire?
11. E-Liquid and Tank Safety
12. DIY E-Liquid Safety

Part Three: E-Cig Mod Safety

13. Minimizing the Risk of E-Cig Mod Explosions
14. E-Cig Mod Battery Safety and Ohm’s Law
15. Rebuildable Atomizer Safety
16. Mechanical Mod Safety
17. Wick Safety
18. Drip Tip Safety