Box Mod Battery Safety
Today, let's talk a bit about battery safety, maintenance, and replacement. How can you care for your batteries to get the most out of them, what should you look for as a sign of danger, and when do you need to recycle them?
First, make sure you're using a cell that's adequate for vaping – Sony, LG, and Samsung are the only manufacturers currently making 18650 batteries suitable for vape use. Any other manufacturer that claims to have a vape-safe battery is taking "seconds," or castoffs from one of the major manufacturers, and re-wrapping them, often including fake specification on the wrapper. Any other manufacturer. Period. Look for a battery that has a continuous discharge rating of 20 amps, or 30 amps if you're wanting to go above 75 watts with a single battery or 150 watts with a dual-battery mod. There is no such thing as a 35 amp or 40 amp battery. Period.
Now that you've got good cells, get a good charger to use with them. We recommend the Nitecore series, but the Efest LUC and several Xtar models are also good. Many mods these days have a micro-USB port for installing software updates or on-board charging, though it's advisable to charge your batteries in a standalone charger whenever feasible – keeping two or more sets of batteries on hand makes it easy to always have a fresh set on hand for installation when it's time to charge.
Inspect your batteries regularly for signs of damage – is the positive contact bent down, or are there any signs of rips on the battery's wrapper? Have you ever felt a battery either inside your mod or as you've removed it getting hot to the touch (warm is normal, HOT is not)? Have you witnessed steam or liquid coming out of your battery at any time? These are all signs of damage – while replacement sleeves can be purchased to re-wrap batteries if the only problem is the wrapper, any of these other conditions are signs of serious damage and you should immediately and permanently discontinue use of a battery that's exhibited any of them.
Absent any sign of damage, how long will your battery last? Generally, lithium ion cells have a lifespan of about 300 charges – as long as they're not excessively depleted, expect them to charge 300 times before they show significant signs of decreased life between charges (though they'll naturally lose a little charge life as they age, even before this point). Try to charge your cells when they drop below 50% on your mod's charge indicator – this measures battery strength at rest, when you're vaping you're actually drawing a lot more power. Draining your batteries too far between charges can mean they'll start to deteriorate at 150 charge cycles or less, effectively cutting your battery's life in half. A fully-charged cell has 4.2 volts of power, try to charge them when they drop to 3.7 volts but definitely don't let them drop much below 3.3.
As far as when it's time to drop your batteries off at the recycler (please don't contaminate landfills with the toxic chemicals they contain, Home Depot and many other retailers have free drop-off points), keep an eye on them as they age. Obviously if they exhibit any of the defects discussed above it's time to retire your cells, but if not you'll still begin to notice less and less quality vape time between charges at some point. So long as the batteries are still functioning you can continue to use them, but with the relatively low cost of replacement you may be more satisfied upgrading before they fall entirely flat.