I have three ego V batteries they are all variable voltage, and all have bad boards/switches. These batteries are pretty good however I work at a job where frequent drops occur, and they can only handle so much soldering. I am ordering a new battery just to gut and build my own. I like the variable voltage and the lcd display that changes colors. I plan to take all four batteries and solder all positives and all negatives and solder them to the lcd board. Simply I plan to take an e cig and add a couple more batteries for more battery life. I am thinking this is possible, however I don't know much about small electronics. I imagine it would be the same as hooking up multiple batteries in a car, nothing gets fried, it only increases capacity? I think the volts and ohms would remain the same as one battery by itself, however I don't know if the wattage would be the same. I really hate to fry a board if I don't have to, Any advice would be awesome.