I don't think the MV VV PT has that sort of protection circuit, but it may. It's a pretty simple device. But even if it did, since the dual coils are in parallel at 1.5 each the device should see it as standard resistance? At least that's what I thought. Maybe one of the coils is not firing on that particular carto. I have a VV box that won't fire my 2.0 cartos, they trip the 145000 protected batteries, what a pain. But I won't use unprotected since I saw a pic of one that exploded a device. Pretty dangerous if you ask me.
Parallel ~3.2 ohm coils are seen as ~1.6 ohms. Most passthroughs have an amp cut off whether it be that the switch can only take so much or an actual protection circuit or that the power source can only produce so much.
Unprotected batteries: Well, that's a topic in and of itself. It depends on the chemistry and design of the battery. Lithium Ion batteries used in mods need to be protected. Unprotected li-on rechargeables are not safe for vaping, and especially so when stacked. LIMN chemistry (IMR batteries), Ni-MH chemistry, and the lifep04 batts and a couple of other safe chemistry type batteries require no protection circuit. For instance Ni-MH cells are individually vented and a venting failure produces a very small amount of hydrogen - and that's about it.
Occasionally, a safe chem batt will have a catastrophic failure and I've seen a few sets of photos of the results here on ECF (among other places). Occasionally, a protected li-on battery will also have a catastrophic failure. I have personally seen batteries fail in all three situations where failure occurs - over charge, over discharge, and short. Some of those were safe chem batts and some of them were li-ons. There is a thread in this section about an eGo-t battery that flamed out, and I saw a bulged go-go battery a few months ago, so it can happen even to the commercial mass-produced eCigs with built in circuits.
The last set of battery failure photos I saw here on ECF were of a top-of-the-line AW IMR. The ones before that were a protected trustfire - and the ones before that were from some tenergy li-ons (failed while stacked). -- It isn't a common occurance, but it is something that anyone using rechargable batteries should be aware of.
So, my conclusion is that as long as unprotected li-on batteries are completely avoided, your chances of experiencing a catastrophic failure is equally low across the common battery chemistries.
(My eGo VV works with everything once the post is raised.) I was able to get the eGo Mega Carto to work by lifting the posts and everything else I have works okay. I don't have any other DCs to try but it appears the skirt on the EMDCC is too long and not allowing it to make contact? Or the VV eGo PT might have a deeper well where the center post is??
