Okay, makes sense. But as far as I know the BLF charger was meant to be made of aluminum whereas the UT4 is made of plastic.
I'm not sure if DLYFull will be using the same tools again. Will they?
Absolutely necessary. 76mm at least, preferably 78mm.
If the bays are under 76mm, then there should at least be banana plug connections for an external cell holder.
Yes, of course it’s necessary.
Is this not the charger that does everything?
How long are the protected Sofirn 21700 batteries?
I know every time I shoehorn them into my Zanflare C4 I’m afraid I’m bending something.
Not too sure how it happened, but I’m embarrassed to say I voted the wrong way 
Must be getting older than I realized.
Anyway when the votes are finalized, if it’s possible please add one to supporting the longer option and subtract one away from the other.
You can cancel your vote and yust vote the other way :)
Is this because they have a die already for plastic ? Is this - “we are going with aluminium.” no longer the “case”? It would suck to have a buy another charger for the protected cells.
I like the idea of banana plug connections whatever the bay size ends up being 
I really want an aluminium charger, which is why I’m making this poll.
All of the people I’ve spoken to have said this is a good idea, so I want to make this reality.
This seems an interesting workaround/solution (for people who want it, can purchase option). How difficult would it be to have such kind of connection (eg. in the future, longer batteries become available, we just need a longer external cell holder)?
I've not been into flashlights long, but it seems like I'm seeing increased interest in lights with larger cells than the old standby 18650. I haven't invested in any 21xxx lights (yet) but that will likely change no matter how much I resist "cell creep".
I voted for 78mm. compatibility (and/or banana plugs) just for future-proofing.
slmjim
Usually, battery-charging devices are designed so that the only electrically-conductive exposed parts are the contact pads for the ends of the batteries. Making the entire thing out of a conductive material adds additional risks. Anodizing the aluminum would probably help a lot, but it’ll still be important to take care about things like scratches in the anodizing or damage to the battery wrappers.
On the plus side, an aluminum charger should handle heat better. On the minus side though, it increases the chance of shorts, so extra care should be taken during use and with the overall design.
yeeaah I’m not too sure how I feel about it being alluminum. I would rather it just be larger or have louder fans lol.
I love the additional slot(would be nice if there were enough for all 4 slots, I can drra.) for banana connector.
I vote for longer
@Toykeeper, you’re right.
Another alternative would be to use small heatsinks inside, but while that would decrease material costs, using injection molding would make the charger that much more expensive.
One alternative that would make this very nice would be a dual finishing process.
We’ve experimented this at my plating job, and it was a thick anodizing coat(30um) along with a powder coating finish for additional durability and electrical insulation.
Perhaps that could be of order.
I’d love a charger that fits everything… including charging 4 x 26650 simultaneously.
Anodizing AND powder coating? PERFECT! 
The opportunity to support protected 2x700 cells sould not be missed imo.
Could it be made pink? 