Here’s some basic information mA and mAh in general. This is not intended to be too technical and I am not an expert (so keep that in mind) it is just and introduction to the terms used to those who may not be technically inclined like me.
First let’s go over battery Capacity
Batteries are rated "mAh", (which we write as “mah” at the end of a large number like 650mah or 900mah) and is based on current capacity (ampere-hours). Each battery is composed of one or more cells (usually one in a standard ego battery) . These cells are storage areas for electrons. When the battery button is pressed and there is an atomizing device attached these electrons rush out to fire the device, mAh is (in very simple terms) the amount of electons in your battery. If you have more, the number is HIGHER, if you have a lower number you have LESS. When all of the electrons have left the battery and have gone into your atomizing device powering the atomization of your eliquid , the battery is dead and the current flow ceases. Current capacity (mAh) is the approximate “charge life” of the battery. This is why, in general, a higher mAh number means a larger or thicker battery.
The bottom line is that the higher the number the larger the capcity of your battery and the longer it will last between charges.
Now onto charging...
All of our charging cables have a "mA" rating. mA is an electrical measurement, it has nothing to do with your battery capacity, instead is has to do with current flow. This rating is used on battery charging cables. It tells you how much flow is going back into the battery. Let’s take the standard 420mA charger for example. If your eGo battery was rated at 420mAh, then the charging cable would charge your battery to full capacity in approximately one hour. However, I have never seen a 420mAh battery so let’s use the more commen 650mAh as a real world example.
A 420mA charging cable would charge your 650mAh capacity battery in 1 ½ hours.
650/420 = 1.55 (rounded)
A 420mA charging cable would charge your 900mAh capacity battery in just over 2 hours.
900/420 = 2.15 (rounded)
The bottom line is that the higher the number on the charger the faster the battery charges.