An introduction to battery safety
1. Buy the right batteries
It's very important to use the batteries for the job. Pushing a battery past its capabilities will lead to poor performance, and possibly cause the battery to vent or explode. Batteries used by power vapers have no protection circuits, high amp limits and relatively small capacities.
Here are two batteries favoured by power vapers -
Sony US18650VTC4 - this battery has a 2100 mah capacity and a 30 amp limit
Samsung INR18650-20R - a 2100mah capacity and a 20 amp limit.
Both of those batteries have low internal resistance and high amp limits, that means they will perform better than regular batteries (deliver more power to the coil) and do it safely.
Do NOT use your regular batteries to run sub-ohm coils. This is a specialised area and requires specialised tools. Always check your battery's amp limits before using them.
list of batteries and their ratings in following post
Remember - owning a 30 amp battery doesn't mean you need to use it at 30 amps. A high amp battery gives more headroom and will perform better - that's the reason they've favoured.
2. Buy the right charger
Don't skimp on the charger. A good charger has numerous safety features and will charge your batteries to the correct level. I use a Nitecore Intellicharger I4, other quality chargers can be found from manufacturers such as Xtar or Efest.
Here's a link to in depth reviews on chargers -
A four bay charger is worth considering if you're a power vaper - battery changes might be more frequent than you think. Some chargers allow you to check the voltage level of your batteries, always a handy thing to know.
Do not leave a charger unattended. That means no charging overnight! Charging bags can be purchased - the charger is placed inside and the bag offers some protection in case of venting. At the very least, always use your battery charger in a safe area away from flammable material.
Check that the charger is suitable for charging 4.2v batteries. Check at what rate the charger will charge (typically 0.5a or 1a, maybe 2a, sometimes selectable) - the larger the number the faster the charge, but you shouldn't try to charge small batteries such as the 16340 at a high rate - always refer to the manual.
Chargers which plug straight into a two pin adaptor should generally be avoided. There's been reports of unsafe electronics and wiring used and it's not worth the risk to save a few pounds. Do not use a cheap charger to charge your quality batteries. It's a false economy
3. Source batteries from a reputable vendor.
Batteries are easy to fake, so it's important to know that what you're buying is the real deal. If it's too cheap, it's probably a fake - AW IMR fake batteries in particular are quite hard to spot.
Here are links to the two batteries mentioned above -
The seller is used by many members here and is trusted. Remember - if you're not sure, don't buy. A fake battery is not only a rip off, but if you attempt to push it past its limits (which without specialist equipment are impossible to determine) there's a possibilty of venting and explosion. Not worth the risk, always put safety first. If you think you've been sold a fake battery, contact the vendor and ask for proof of authenticity. Do NOT continue to use the battery.
4. Capacity and voltage drop
As mentioned above, the batteries used by power vapers tend to be of lower capacity, typically around 2000mah. The demands placed on the batteries mean that a battery can rapidly run down from 4.2v to 3.2v. That means you may be changing batteries more often; it's important to change batteries before they run at a voltage level which may permanently damage the battery. Check the specs for your battery - that level will probably be around 2.8v.
However, that doesn't mean you can run the battery down to 2.8v. Under load (When you're firing the atomiser) the voltage drops, sometimes quite significantly.
For instance - a battery is reading 3.5v, but under load reads only 3v. To be safe, always give yourself some leeway. These batteries aren't cheap and to get the most out of them it pays to be careful.
At the same time, much of the capacity of the battery is found in the lower voltages, so if you keep a close eye on your voltage levels you can use more of the available capacity.
You can test voltage level and voltage drop with a multimeter (terminals on the positive and negative post of the mod or atomiser) or an easier option is a tankometer -
The tankometer is screwed into the mod - you fire the mod and the voltage level is displayed. That's the voltage of the battery with no load. You can then screw an atomiser into the end of the tankometer, fire the mod again, and the voltage under load is displayed.
You'll soon learn to recognise the point at which you need change the batteries (most power vapers seem to change them around the 3.6v mark) but it's worth investing in a means of accurately testing the voltage level - it's an indispensible part of any vaper's toolkit.
5. Stacking batteries
IMPORTANT - To vape at high power levels it's NOT necessary to use stacked batteries. Stacking batteries is for advanced vapers who observe strict safety precautions. Failing to follow any or all of the following advice can lead to batteries venting or exploding. Please read the information carefully.
Stacking batteries is a way of delivering a higher voltage to the atomiser. So two 4.2v batteries in series (stacked) will deliver 8.4v. Stacking batteries is safe, provided you follow the rules. Always stack the batteries in the right way - with one battery's positive button on the other battery's negative contact, and in the right direction - battery's positive button to the positive centre pin.
A) Keep your batteries in pairs
Mark your batteries to help you recognise that they're paired. Use an indellible marker to label each pair of batteries (A, B, etc).
B) Keep an eye on the voltage levels
Test their voltage level as they come off the charger. They should read the same.
C) Alternate which battery goes on top
This helps keep the batteries balanced. Power is drawn from the batteries at slightly different rates when stacked, so alternate them between charges to even it out. Again, mark your batteries to help you recognise which is which. For example - your pair of batteries is labelled A, and each battery is labelled 1 and 2.
D) Do not exceed their amp limits
A pair of 10 amp batteries in series still has a 10 amp limit. Typically when using stacked batteries you would build a coil of higher resistance. You can deliver the same amount of power (watts) but at a higher voltage and lower amperage.
E) Change the batteries at the right voltage level
Voltage drop may be slightly lower when stacking batteries, and voltages remain relatively high even when the batteries are almost flat, so it's important to keep an eye on what the batteries are putting out. Again, test them both without load and under load and stay well above the bottom limit of the batteries. So rather than change a single battery at 3.5v, you would change a pair of batteries at 7v.
6. Use a suitable mod
Power vapers normally use mechanical mods. A good mechanical mod will offer a safe and superior experience. That doesn't mean the mod has to be expensive, it just needs to have certain characteristics.
If your mechanical mod doesn't have a way of allowing a battery to vent, you shouldn't be using it, for power vaping or anything else. Check with the retailer that your mod has suitable safety features.
B) If it says it's mechanical - check it's fully mechanical
A fully mechanical mod will allow the full range of power to be delivered to the coil. That means no wires, no PCBs, just a tube, a switch and a 510 connection.
C) Low voltage drop.
A low voltage drop means more of the power from the battery can be delivered to the coil. That means less waste, a more powerful vape, and fewer battery changes as more of the capacity of the battery can be used. Check out reviews before buying.
The switch is vital to the proper flow of power. A flimsy spring or loose fitting part can lead to lost power and the switch heating up at the expense of the coil. If you feel the switch, or any other part of the mod, getting hot, stop using the mod and ask on the forum what you can do to solve it.
D) Keep everything clean. Dirt leads to lost power. Once or twice a week give everything a clean, paying special attention to the threads and contacts. A wipe of isopropyl alcohol may be enough, a nice ultrasonic bath, or simply good old soap and water.
7. Coil resistance and Ohm's Law
This will be covered in another sticky, but is worth briefly mentioning here too. Always check the resistance of your coil before placing it on your mod. This can be done with a multimeter or a dedicated ohm reader.
When using a mechanical mod, the only way of controlling the power delivered to the coil is by changing the resistance of the coil. A 0.42 ohm coil will pull 10 amps from a 4.2v battery, a 0.21 ohm coil will pull 20 amps.
If you check your resistance and you're not sure what that means in terms of amp draw, input it into this online calculator using 4.2v as the voltage -
Dont run coils right at the limit of your batteries, always leave yourself some wiggle room as coil resistances can fluctuate for a variety of reasons.
8. If you're not sure, ASK!
If you follow this basic introduction to battery safety you should be well on the way, but if you're not sure about any aspect of it then please just ask. There's any number of people on the forum who will be happy to help.