Been working quite a bit, for weeks now, on trying to figure out the best way to make-use of a literal stack of USB battery-packs I got for a steal...
I haven't the energy to go into the details of half a spiral-notebook's worth of thoughts, right now, but the basic conclusion is to put them all in series for 40V 2A [80W for two hours!] And use a bunch of DC-DC converters to make it basically a multipurpose portable power-supply. I lucked[?] on a steal for 12 floating/isolated-output 5V 6A buck-converters for the cost of a couple meals at a drive-thru. No joke. These ain't yer no-name-brand modules, either, we're talking any one of these would easily be worth what I paid for all of them, even used. We're talking the sorta devices used to power servers with multiple redundant slide-out power supplies each attached to a dedicated UPS. We're talking... surplus is awesome.
Did I mention isolated-outputs? That means you can put all the inputs in parallel [40V] and the outputs in any series configuration you can think of. And they're [slightly] adjustable, so three in series, set to 4V will give 12V@6A.
Wasn't exactly planning to put *all* may battery-packs "in one basket," but this could be quite the tool.
Today I was diggin' the radio... rare I wanna keep listening to the same station for two+ songs after I park...
Occurred to me it wouldn't be difficult to tap into the "accessories" wire from the key-switch, and run the stereo [and more] off the new power-bank.
Might become a thing... tinny speakers are lame.