Hi, Just a few things - you may know these already.
1. Don't leave your batteries on the charger unattended, and don't leave the charging all night while you're sleeping.
2. Remove your batteries from the charger when they are charged (light goes green). Give them a rest time before using them in your mod.
3. Keep an eye on your batteries condition. If you notice rips or tears in the exterior don't use them.
4. If you are using two batteries at the same time in a mod then charge both batteries together and use the same pair of batteries. Don't mix up an old battery with a new one. ETA: I don't like to stack batteries in a mod myself (see ECF link below) , but some mods do take two.
5. Invest in a digital multimeter. These can be bough quite cheaply and then you can check the battery voltages.
6. From the ECF
http://www.e-cigarette-forum.com/forum/ecf-library/129569-rechargeable-batteries.html
"IMR Li-Mn rechargeables
Manufacturers include AW and BDL. AW are reported as higher quality. These batteries are unlikely to explode in use and there are no reports of this occurring (but they can melt down with flames if abused by for example short-circuiting or APV switch lock-on). They are recommended in place of Li-ions and do not need protection. These batteries are of high quality and are therefore expensive - but you get what you pay for."
Notes:
- No memory effect.
Cautions:
- They have a high current discharge potential and therefore it may be wise to have a protection circuit in the main device. The discharge rating is often 8C, meaning it is likely that a lot of amps would be available if the battery were to be short-circuited (= a dead short or shorted-out).
- They will be overcharged by old-technology chargers and may burst.
- Overcharging (>4.25 volts) will shorten the service life, which is 500 charges under ideal conditions.
- Discharging below 3 volts will shorten the service life.
- If you run a Li-Mn down below the minimum discharge voltage, the cell can be damaged. As there is no 'trip out' as with a protected Li-ion, this is a concern.
You can extend the service life of these cells by not recharging above 4.15 volts or discharging below 3.3 volts.
I recommend reading that whole page.