Joel's work on the Grasshopper external battery was quite an awesome effort.
It came before the also awesome MaxVapor adapters.
I seem to remember Joel got to 100 chambers of battery life with his attached box of 4 x 18650s - the GH is crazy efficient. But everything got complicated by the finicky electronics of the Grasshopper. There is some kind of communication protocol used between the threaded rear end and the front chamber through the body.
I think weird issues cropped up with device malfunctions, and Joel eventually gave up and moved on. It might have been caused by his added mods, or it might have been a case of the major manufacturing defects never corrected with the Grasshoppers.
My own experience with the MaxVapor 18650 sled was not so good. It shipped with a battery holder intended for a longer battery with nipple. Most in this scene are probably familiar with the typical suitably powerful flat-end type. Using an LG HG2 I bridged the gap between battery and terminal using a copper staple, which probably caused a less than ideal connction.
Whatever the case, one of the very few times I used it the back end got scorching hot (way, way beyond any surface temp of a notoriously hot Grasshopper).
It might have been the io, I can't remember but I think the back end temp dial seized, maybe caused by melted plastic if it was the io or maybe just metal expansion otherwise.
I had a lot of warranties and units so it's pretty hard to remember specifics there, but it was a lame moment and a little painful.
I only had success with the MaxVapor mains power adapter with slotted adapter. I had to use a beefy power supply (Meanwell LRS-100-12) to power the io
The adapter kit includes a step down transformer to convert 12V to the 4.2V expected by the hoppers.
Instant on, and it really was. I had a great time with these pens for years and years.
It is nearly a decade since I preordered my original!
I still have my flawless cooler running (to spec, 210°C ie. too cold) HT Ti 2017 unit and it's as good as day 1.
The units running out of spec (240°C +) was why I loved most of my experience with a bunch of other units. Better than TM2 but only for a while. So much smaller, too sleek for its own good.
Such a wild ride, but it's easily the most convenient vape ever made. Somewhat unbelievable from conception to now.
I wish they got it right. It was so close and so amazing! I still think everything else is poor by comparison, but also can't deny the many issues.
@Adobewan The idea behind the power adapters is simple - using a dummy battery feed in 4.2V (45W for Grasshopper, 75W for io)
I would 3D Print a battery sized piece that can house wires soldered to serrated gold pogo pins.
To feed in the DC wires (which can be thin and flexible and quite long - think G43), you could mill a slot or drill a hole into the side of the hopper body, or lathe a threaded adapter to fit between the back end and body (extending the distance between contacts requiring the dummy battery to be longer than standard).
It's going to take a bit of work but it wouldn't be particularly difficult otherwise.
One day I will retrofit the MaxVapor kit to my TM2.
Lamart used to have an unsurprisingly nice power adapter for their Tubo Evic. I couldn't find a picture but that's how I got on to the MW PSU I selected for my io assembly. My io's unfortunately lost performance after a while but they were great for a while. I got my moneys worth and some. These were oversold sold and too cheap and now we are left with poorer choices that are more costly.
The airflow is a bit restricted but otherwise these ultra portables were pretty much as good as it gets for my usage needs.
I will say that having the power adapter and tethered device is much more cumbersome and the main benefit for using a hopper is a bit limited as much of the convenience is lost. The vape had a great signature, but compared to a ball vape or my sublimator, the fact the hopper is immediately transportable because they are cool/insulated was useful, but I would think that a ball vape is a better path forward today along with a TM2.
Not enough advanced insulation is being used on vapes. it was one of the big functional features of the Hopper design and why the efficiency was so good and the device immediately ready and immediately pocketable after.
I got the Xmax Nano to try and it's nowhere near as good as my HT Ti Grasshopper in any way.
The GH units were the Zune and not the iPod I really thought they could be.
Not even the iPod is around anymore though.
The GH was fantastic in terms of fucking combustion. Glad I got to enjoy it for as long as I did and hope others can still enjoy theirs.