I have been a long time enthusiast of high power flashlights. We typically use 18350, 18650, 21700, or 26650. But I have been in dismay as even in this community, companies are starting to move away from these standards and provide proprietary batteries (Olight) or sealed (some newer Fenix models). It would be good if * We could safely obtain reputable Li-ion batteries from reputable sources. I trust a handful of com…
Regarding sealed: Does the light really outlast the battery? I have some LED lights that have lasted "forever," but my aquarium lights don't seem as durable and I think only will last 5-7 years. (Fluorescent bulbs only lasted a year, and each bulb cost almost as much as an LED version.)
I'm not sure how your aquarium lights are configured (whether they cycled or were always on) but honestly 5-7 years is already quite impressive. There's not really any other lighting technology that can do that. 5-7 years of constant usage also far exceeds what consumer batteries can usually do, which are something on the order of hundreds of "actual cycles" before significant capacity degradation. That translates to maybe a couple years, but definitely less than five.