There are many places on the Internet where you can find out about batteries but this counts for nothing if you purchase a clone by mistake.
Brand names like Efest, Panasonic, AW, Sony, MNKE should only be purchased from highly recommended suppliers. Some brands like AW will only sell through authorised resellers and there was a spate of clones on the market recently. In short, do your homework.
There are many good forums like Planet of the Vapes and UK Vapers where people will answer your questions.
A good vendor will be able to provide you with the performance details about the battery. The good news is that there are a growing number of batteries able to cope with a constant current of up to 30amps. With all vaping, ensure that your battery uses â€œsafe chemistryâ€ and follow Rule.1: Never scrimp when buying batteries.
From when you first started coiling your atomisers you ought to have drummed V=IxR into your mind, where V is the battery voltage, I is the current in amps and R is the resistance in ohms.
To find out what current you are sending through your mod you need to divide the maximum battery voltage (commonly taken as 4.2V) by the total resistance.
When you are measuring the resistance of your atomiser make sure that you use a quality ohmmeter (like this one) capable of reading to two decimal places.
If you donâ€™t know how to work out the total resistance when you place coils into parallel (dual/tri/quad) then bookmark this page and it will work out the total resistance for you.
Current from a fresh 4.2V battery
When you are vaping at low ohms you might want to consider using a lower nicotine liquid than you would normally vape. The volume of nicotine entering your body is greatly raised and you can suffer from headaches and nausea. Serious cloud chasers often opt for a zero nicotine high VG liquid.
As a final caveat, in some research carried out by Doctor Igor Burstyn and Dr Konstantinos Farsalinos it has been identified that acrolein and formaldehyde are formed at high temperatures/low ohms/high currents/high voltages. Although there is more research to be completed in this area, to discover at what quantities and how harmful, it is one reason why some people shy away from low sub-ohm vaping.