Ok thanks guys for explaining that, it makes sense. The only thing I don't understand though is why use a VV with a LR carto at all if you can only use it 3.7? That seems a bit backwards to me.
I use a LR carto with my vv devices because I happen to like the way that particular brand performs. Plus with the brand I like to use.. it's hard to find them (higher ohms) in SS for my tanks. (Hate peeling stickers!)
For me it's not about seeing how high I can go, but also the regulated voltage I get. With many 3.7 devices, the voltage continually drops as the batts are depleted. I want to set my device at a certain voltage and have it stay there instead of dropping. I have lots of LR cartos that I bought back before I got the vv devices I own. While I do buy higher ohm cartos, I still want to use what I have. With a carto at 1.7ohm.. I still like to vape it at 4v.. a 3.7 box mod will actually give that high of a voltage when it's fresh off the charger but it doesn't stay there long. I was continually changing my batts for fresh ones when the voltage dropped.
My Lavatube will not run my 1.7 smoktech cartos any higher than 3.7.. no matter what the led readout says, the voltmeter tells the real story.. and that's not good enough for me. My other vv devices will. So if I use my LT, I have to use the higher ohm cartos.