Not so sure you want to stack batteries in something completely mechanical... I don't know if the VMod even has a hot spring. That could be bad especially being a plastic body. The plastic could melt and potentially create a permenant bond with the contacts of the battery(ies). One of the biggest downfalls to ALL bottom feeders is the ease of flooding the atty / carto. It's much harder to do with a carto, but it's possible. Another downfall is how easy it is to use which eventually will equal lots of money spent on liquid.
The VMod seems like a good entry point, but how much would be too much to spend?
One pretty big drawback with a VMod is that it doesn't have a tube in the bottle. This means that to get juice where it needs to go, you have to turn it upside down and give it a good squeeze. This is bad because you have no idea how much juice it getting there. Having a tube, you can take a dry drag on the atty/carto WHILE squeezing the bottle and here a gurgle come up the tube. This is known as "blind squonking" and it's VERy useful when you are in the car or doing something else where you can't fully concentrate on your mod.
I'm not saying you HAVE to buy a REO, there are other capable bottom feeders out there with the same functionality as a REO, but I would like to save you from wasting money as well. If you want to stack batteries, atleast get a REO Grand or REO VV. The Grand has a small safety feature, the hot spring, that has been tried and true to doing it's duty. The VV has circuitry to protect you even further. They really aren't that much more than a VMod Xl and you will be much happier with the build quality and performance.
