I am not one to break out a volt meter and test my batteries but I did notice the difference in experience of vaping with a shorter cut off on the battery. I like the 10 sec cut off. That being said, I found this whole voltage issue interesting and thought that there was a very informative post on the V2 forum on the topic. I will cut and past it here for those with interested. Keep in mind I think this is from someone at the company..... here you go "this is quite a complicated discussion.... in the beginning, we had a 3.7 volt battery, which we were selling until about mid-august 2010 (this battery actually ranged in operating voltage from about 3.2v to 4.2v depending upon level or charge, age of battery, how heavy it was used, and a few other factors... at that time we were unhappy with the initial battery performance because 2 of the suppliers in the supply chain of that production line were providing internal components to our factory that were having defect percentages outside our required range.... Then in mid-august we released a new battery which we called the "4.2volt battery"... this battery was completely redesigned on the inside and was consistently reading 3.9v-4.5v (usually around 4.2) with a full charge, and was holding these readings well after 25+ charges... this battery had less inconsistency than the prior line especially with operating voltage... this battery had a 10 second security cut-off designed in the chip, and became the V2 standard from about mid-august through late October... Then in late October we switched up the supply chain again, because we found a better battery that seemed to stay constant around 3.7v even after 100+ drains and charges, it was by far the most stable battery we ever tested... unfortunately when we introduced this new battery our 10s cutoff circuits were not working well with it (for a number of reasons)... so we switched to a 5s cut off switch, that was operating great with the newest battery iteration. We have since re-engineered the cut-off back to 10s, but those have yet to go into production, and likely wont hit market until March. Regardless, at present the V2 battery is the most stable we have ever sold, it is staying constant around 3.7 with very little degradation after continual recharge. Despite all of this our support department has begun to get complaints that people preferred the prior 4.2 volt model, which in all tests was actually less stable in voltage... Now, with all the technical jargon out of the way, here is the funny part... whether the battery operates at 4.2 volts or 3.7 volts, there is next to no difference in actual vapor production. We know this because we have a machine which measures vapor volume by literally "dragging" off the battery... we measure factors like vapor temperature, vapor thickness (ppm - particles per million), etc. --- to actually achieve a substantial difference in vapor thickness we actually have to exceed 5volts (of course, when we do this, we burn out the cartomizers almost twice as fast

... at the end of the day, the battery we were selling from mid-august to late October, when compared with the battery in current inventory has no noticeable loss in performance, aside from the 5-second security cut-off, which can be annoying to a heavy user (although it is much safer for them)... with this said, we will be going back to 10s cut off, as people seem to prefer it, and we will be trying to normalize the voltage at 4.2 again, but don't expect more vapor when we make this voltage change, because voltage variance of 0.5v will have little effectual difference... it is the resistance of the coil in the cart, and the effective current (not the voltage), that we are trying to improve. These factors have a far greater impact on vapor production. In my opinion, what is really happening, is that people don't like the 5s cut-off switch... and they think because the battery stops producing vapor after a 5 second sustained drag, that there is something wrong with the battery. Then they pull out the old volt meter and say, "3.7 that must be the problem"... in reality, I think your problem is the cut-off switch, not the voltage!... either way we are fixing both, but manufacturing takes time

"
DWZ