You have
joyetech's eGo-c "Upgrade" usb passthroughs. And while they say there's a vv mode, it isn't true vv like the eGo-c Twist where you can dial in a particular voltage.
There are two modes on the eGo-c upgrade batts. One is the same as a regular eGo-c batt where the voltage is regulated to a constant 3.3-3.4 volts throughout the whole charge of the batt. They call the other mode 'vv' but what they mean is that the voltage varies in the manner that a non-regulated battery works. Off the charger you have around 4.2volts, and then it goes into the normal voltage curve of any 3.7v rated battery - for most of the charge you're
vaping around 3.6-3.7volts and toward the end of the charge the voltage begins to drop to 3.2v at which point you need to recharge the battery.
The result is that the "vv mode" runs a bit hotter (around 1+ Watt hotter) and may be better for stronger flavors. I have one flavor where I use the vv mode - a
tobacco type flavor, but for the rest of my flavors I have the batts in "constant mode". The reason I buy the upgrade eGo-c's is that they are the same cost as the regular eGo-c batts where I buy them, so it's nice to have that option.
