I don't have my Deus plugged into the wall while detecting and have to deal with no less than three lipo batteries (4 if you count the XP pinpointer) on a single detector (coil, remote, and headphones) and have never run out of juice on an all day detecting session even while leaving the thing running during lunch and breaks (we are not talking physically larger batteries here). I have also never had to replace a battery in three years of owning the detector and it shows no signs of lowering capacity (great I probably just jinxed myself). So I am biased as far as embracing non-replaceable lipo batteries for detectors.
Ok so what does this have to do with the Equinox:
The choice of a built-in, non user replaceable battery helps with ensuring a robust overall water tight design.
A drain test run by one of the Equinox testers verified that the battery lasted for 12 straight hours. YMMV but there is no doubt, if you embark on a day long detecting session with a fully charged Equinox battery, your body battery will likely run out before the Equinox's does.
Even if you forget to charge the Equinox or you are planning on running it more than 12 hours straight, it can be powered from just about any of the ubiquitous and cheap external cell phone power banks available at 7/11's everywhere (just like the old AA battery analogy) using the supplied USB charging cable and magnetic connector. The only drawback to this approach is if you wanted to take the Equinox for a dunk then on the fly charging/powering would be highly discouraged. [Note that the Equinox can only be powered by the external pack if you are operating the machine. If the machine is de energized, then the external pack will charge the built-in battery].
Properly prep your gear for the next day's hunting and you should have no limitations. But if you do forget, you can charge the thing on the way to the hunt site or power it up in the field with a battery bank as described above.
I kind of got over the whole non-replaceable, lipo battery thing once I converted over to being able to jump start my car with a lipo emergency battery pack the size of a paperback book.
Don't fear the Equinox...
BTW not belittling the trepidation regarding non-replaceable rechargeable batteries in detectors, I get it. My phone battery run time sucks, too.