Rechargeable E Cigarette Battery Charging Tips
Rechargeable batteries have some safety issues when charging.
Batteries should be recharged on a metal surface and should not be charged unattended. For ultimate safety, batteries should be recharged in a Li-Po charging sack, or within a cookie tin (cake tin, biscuit tin) that has gas vent holes drilled in it (any gas vented during charging is likely to be hydrogen).
It is much more likely that lithium ion cells will suffer from incidents while being recharged than while in use. Do not leave these batteries unsupervised when charging.
Do not leave batteries on charge after they are fully-charged.
Do not leave a charger plugged in - unplug it after use.
Periodically check the voltage of a charged battery with a multimeter - it should read 4.2 volts for a regular 3.6v cell ( 3.6v and 3.7v cells are the same thing, the nominal voltage of the circuit is around this value, it is just that there is no agreement whether to call them 3.6 or 3.7v).
If a battery comes off charge at 4.3v or higher then the charger is faulty and must not be used.
Do not charge 3 volt cells on a regular charger, they need a special charger (which completes at 3.6v).
Lithium ion batteries of any kind are not safe in absolute terms, they have known risks. The very high charge density and low cost come at a price: instability especially after misuse or damage. In fact you could say these cells are intrinsically unsafe, because they can meltdown or even explode under certain circumstances, while this is rare or impossible for other types.
Treat lithium ion batteries with respect. They are like a fierce guard dog: they do a good job but there is a price. Mistakes may have consequences.
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 set you previously charged, and that have rested for several hours.