This may sound a bit mad but over the summer I started building a solar powered modular out of CMOS chips and for recording I managed to get hold of a 12v battery to power my 4 track cassette and it worked like a charm (the multitrack was rated for 11v - 15v DC centre positive).
I think it was a 6800mAh battery off eBay that was advertised for use in CCTV cameras. I managed to record for a few hours and it didn’t run out of power during that time.
As long as your recording device accept DC and not AC you could technically use any recorder if you can find a rechargeable battery. Just double check the polarity of DC jack and you can even use one of those DC polarity adapters to flip the pins.
I have also used the Koma Strom Mobile to power stuff as it takes a usb battery and outputs either 9v or 12v thanks to the internal switches.
Actually, this sort of thing can easily be scaled up to power LOTS of devices over a long period of time. Back in the late 1990s, one of the local amateur radio groups was doing their Field Day (a ham radio exercise in the last weekend in June each year, which is a test of communications in "adverse situations" AND something of a contest as to who can heap up the most contacts) on solar power. ENTIRELY solar. Even at night...since the group was using the daytime to recharge the deep-cycle marine batteries in use via several portable solar arrays. And this wasn't trivial...all of the ham rigs in use were 100 watts output, and the group had three of these on constantly.
Check these guys out: www.dxengineering.com/ This is a ham radio supplier that also offers some excellent solar tech tailored just for these higher-amperage setups. And you can even get AC out of this, since they also carry DC-AC sine inverters also made for solar use. It can get spendy...but if you wanted to do something like going remote and cutting and mixing an entire album in the wilderness, these are the guys you need to talk to.
100 Watts! Thanks for the link, I'll have a look at that. I'm liking the portability of AE so want to get out and spend some time sitting in the fields near my house tracking as soon as warmer weather comes around.