I've been a confirmed stacker almost from the start of my vaping career. The LavaTube proved to me that single battery operation was less than ideal. As the battery discharged the vape suffered. Regulating two batteries down just works better than boosting one battery up IMO. I think the danger isn't so much stacking in a PV but cheapo chargers. One set of IMR 18350s overcharged and ruined. MAN those things got hot!
I am satisfied with one 18650 but if I were to stack I would certainly get a really excellent charger (like the one I got
), especially if new to vaping / working with batts. This charger costs $45 after an applied FB10 coupon code for 10% off and it's free shipping:
Xtar VP1 Digital Charger (digital display)
There are a few things that make it different and better than most chargers used for vaping. First, it has a built-in volt meter accurate to .02v and an LED readout that shows you the charge state of each battery mounted in the charger. So when you put one in for re-charging, it will show (for example) 3.58v ... then as it charges it the volts rise until it reaches 4.19 - 4.20 at which time it shuts off the charge until the batt starts to lose charge again, then it charges it back up to the 4.19 - 4.20. So unlike other chargers, it is actually made to leave the batts in it, unattended, and it will keep them ready for use.
It also has another neat feature... you can set the charge rate by pressing a button to toggle through the choices: 250ma, 500ma, or 1amp. The LED window shows what the selected charge rate is, battery state, and there's an animated progress bar (like cell phones have). I keep mine to 250ma as it is better to charge slowly if you have the time. EDIT: Forgot to add it also comes with a DC car adapter!
I absolutely LOVE this charger as I never have to get out the VM to test the batts... I can see at a glance what the volts are. And it's perfect for using with a new pair of batts for stacking. It charges, monitors and maintains each bay separately, and each bay has its own readout. Also, I have touched the batts when charging and they are never warm.
Aside from all this, (and now this goes way over my head) it uses the recommended algorithms for charging.
The NiteCore charger costs about half as much (and is highly recommended), but I'd rather pay $20 more to not have to use a separate volt meter, and to see at a glance that my batts are in good shape. Especially if stacking, I would not be without this thing. And because I have it, if I ever decided to try stacking, I'd feel pretty safe because of this charger (and the fact that the Vamo is made for stacking and has safety precautions built-in).