Battery Chargers. Get the best charger that you can reasonably afford from a reputable e-cig vendor. Statistically, most battery incidents occur while batteries are charging. A higher end charger will have better built-in protections.
Pila,
Xtar,
Nitecore, and
Efest are the most recommended brands. We recommend batteries be charged on a flame-resistant surface: stove top, marble countertop, metal baking pan, pyrex glass dish. Do not charge batteries if you are not physically present to keep an eye on them.
Many of today's higher-end box chargers have
"intelligent technology" designed for the charger to shut down when the battery reaches full voltage (4.2 volts), however electronics can and do fail. Don't trust the safety of your home & family to a faulty electronic circuit or charging cord.
Some higher end chargers can "restore" an over-discharged battery utilizing special algorhythms. Some have independent charging bays (preferred), some share the power supply between multiple bays (not preferred). Some use simple LED lights to indicate the charging process, while higher-end chargers use real time LED voltage meter displays. Better chargers will allow options as to the speed of the charge, although the slower the charge the safer it is for the battery's long term health.
Rest batteries after charging
One commonly-reported factor in almost all the incidents we hear of where batteries failed violently while in use is that they were taken directly off the charger and then used immediately, at which point they failed.
Because of this, we think it may be a good idea to rest batteries after charging them. This advice will not be found in the usual 'reference bibles' on batteries, but we see more and different reports than others. Therefore we now advise:
Do not use batteries directly after charging them. Use a battery or batteries you previously charged, and that have rested for several hours. This is especially important if using a stacked pair for higher voltage, as statistically the risk is far higher.