Actual use report on the rechargeable Li-ion charger.
The Miller ML 102 with a Panasonic NCR18650A installed recharged the SE, which was down 7% from the day's use, as quickly as a powered USB port, roughly 45 minutes. The iPod Touch, which was down to about one third capacity, also recharged quickly (much faster than the SE, probably due to a much smaller battery). After this tiny orgy of recharging, I measured the Li-ion NCR18650A cell's voltage. It was a robust 3.8V.
A little more on the ML 102: It is both a charger and a recharger. You can charge a single 18650 cell from a standard USB2 port using a USB cable with a micro-B tip, plugging it into the micro-B socket on the ML 102. The same cable plugged into the USB2 port on the ML 102 is used to recharge devices like the SE that have a micro-B socket for recharging.
I'm guessing that the capacity of the NCR18650A cell (3100 mAh) is roughly the same as the SE's battery. I've submitted the question to DeLorme support.
And if anyone has an iOS device with the new Lightning connector (like me), I have this advice. Non-Apple Lightening connectors, even the ones that claim to be blessed by Apple, are not very reliable. I've had to discard two. The Apple cable is still working. I hate to pay $20 for a micro-B to Lightning tip adapter, but that may be the price of reliability. Not strictly passive, it has a chip in it.