First, without knowing what you are using on each one,
tank type/resistance/etc. it is hard to say.
Second.....................your friend seems kind of clueless.
The IPV-D2 is a very well designed Mod with an outstanding chip running things. Knowing proper usage makes for an outstanding experience.
------------------------------------------------------------------------------
Now, if you are using a tank with a to low ohm coil in POWER mode you may not be able to ACTUALLY reduce the wattage as you are hoping.
Screen setting does NOT mean actual output will match.
Screen reading=request
Actual output cannot go lower than Battery Voltage
You can run a standard Kanthal/Nichrome build in TC mode and reduce power to 10w, but you will not actually have Temperature control, just lower wattage.
For Mod reference - watts=Joules
Where are you getting the figure 6v-7v for output?
---------------------------------------------------------------------------------------
You may have a defective unit. If so return it for exchange.
It will be the first we have heard of so far.
---------------------------------------------------------------------------------------
You can find a lot of information and discussion in the APV/Temperature control sub-forum
Plenty of people willing to help out.
------------------------------------------------------------------------
I have been using mine heavily for 3 days now and cannot find any real issues or concerns.
Orchid Tank
Dual Coils .48ohm - Kanthal in power mode
28watts
Orchid Tank
Dual Coils .101ohm Ni200 in TC mode
30J / 400F
------------------------------------------------------------------------
There is an Extremely low chance of ever Blowing up a Battery in this type Mod if operated properly.