I cannot think of a reason why anyone with any experience with APVs would do this, but I was just shown a completely screwed up Vmax. An associate of mine bought a Vmax unit and two Efest batteries about three weeks ago. He's been saying that it works great. He brings it to me this morning and says it stopped working. I unscew the base cap and find two gray labeled batteries with some dried syrupy stuff and black fine grainy powder inside.
It appears that there was no insulation jacket on the bottom of the batteries. I ask him where did he get these batteries. He says they were from a local tobacco shop selling DSE601 epipes and that he was told they would work fine. He shows me two more unused batteries. There is no insulator jacket coverage on the bottom. Apparently the base of one or both of the batteries shorted on the side of the housing.
I tried cleaning and blowing out the debris and seeing if the unit would still function with no luck. I had a 601 way back and I can't remember if the batteries I had looked like these. I had some similar looking ones that came with my MKII Screwdriver but they have a jacket covering most of the - end. Why someone would build a batt like this, i have no idea.
I was debating if I should even bother to mention this and figured it was worth it for two reasons. One, with unprotected lithium ion batteries being stacked and failing, the device's exterior showed no indication that anything had happened. The batteries didn't turn the device into a bomb or anything, so I guess some sort of safety feature kept the owner from serious injury. The batteries say ICR18350 Special Battery Shenzen on the side with a light gray plastic wrap.
The second reason is that someone else could possibly be out there considering doing the same thing. The owner suffered only the loss of the device. Someone else may not be so fortunate. I highly doubt any company will cover this under warranty as well.