I just noticed that my Nitecore New i2 charger will also accept D cell NiMH batteries so that helps.
OK, thinking aloud here and trying to reply to everyone's comments. BTW, thanks all for the help, I really appreciate this. Hopefully this thread will also assist others.
@vicv Those Imedion D cells are definitely out of my price range, however I found a four pack of Tenergy Premium 10000 mAh D cells for $28. That's cheaper than buying the dozen Eneloop AA cells to fill my adapters.
@Macgravy you say the Amazon Basic NiMH D cells are working for you? I wonder who makes them? I have some Basic AA and AAA cells, black with a green band from 2018 and they've been good to me so far. At that time, my research showed they were, in reality, Eneloop 4th generation cells.
So no one has any input of the 18650 to two D cell adapter shown in post #8?
@captianworkbench since the DC option wouldn't be used much, I assume that I'd be better off with Tenergy Centuras than their Premium line?
@Macgravy thanks for the research but honestly I probably wouldn't do any testing if I go with those adapters. They have since become an option again because I can get a dozen Tenergy or Basic AA cells much cheaper than Eneloops. I know Eneloops are king but really how bad are the other brands from a users perspective?
@Schokokeks yep, I know them. I mentioned in post #8, I used the AA to C Eneloop adapters for a spotlight. Though I did no formal testing, I did not notice any significant difference in run time either. Honestly, they
seemed to last a bit longer than primary C cells. This would be the cheapest option for me as I have enough NiMH AA cells on hand to easily fill four adapters. Now you have me thinking, if I'm backing these up with D primary cells, why not?
Just so everyone knows, I want rechargeables for the obvious reason but mainly so I don't have to worry about leakage with them kept in the radio. I will be backing these up with a few reloads of Energizer MAX D cells JIC of an emergency.