I’m also using a 12v, 5A power supply and have recently added the delta fan. Prior to that I placed the whole unit on top of an 80mm computer fan. The Opus works great and I have none of the problems other people seem to have. With the “improvements” I consider it a better overall charger than the Lii-500.
BTW, the Opus power supply works great for the less demanding Lii-500. I got one without the power from Ali for $13.
I started asserting about the possibility of fixing the BT-C3100's capacity measuring flaw by replacing its power supply with an adequately higher powered one some time ago in a few chats. Glad to see some people have also been “enlightened”, no matter how.
All these mods, flydiver, make the Opus BT-C3100 even less budget.
With the newer firmwares (v2.1+) the bursts of power draw seem to be at or under 6A:
Anyway, if I were to aim for a flexible, adjustable voltage and current charger I'd probably DIY one with a set of rails, a 12V power supply, some inexpensive XL4005/XL4015 CC/CV modules, a few voltmeters/shunts, switches, a box, etc. It would probably end up being another frankenstuff thing I usually love so much. 
Cheers :-)
funniest part was him not responding to the proof he was demanding the whole time.
Yeah, that gyzmo2002 guy eventually disappeared (and up to now a no-show) after I showed him the evidence he was looking for.
oh Wolfdog…u just had to post the Ebay links for the PS and Fans… 
…$60 later (1 delta variant of the LiteOn PS from china and a similar LiteOn PS— the PA-1600-2A-LF, plus 2x of the Delta fans —-the PS link was not in stock), I now have upgrades for a charger that I haven’t even taken delivery of yet…should be here tonight!
I also definitely want the SkyRC charger, but am hoping that there will be a some firmware updates that the BLF community have been waiting for.