AMPowers wrote:
[snip]
Alternatively, one could build their own embedded system using a few ICs
(I would suggest checking out the PIC16 micro-processor line from
www.microchip.com) but this approach presumes some familiarity with
electronics.

my thought too, then you could have it stay in place and give you
readings from now until whenever. there are a number of really good
hall effects sensors for measuring current that are easy to interface
to a pic processor's a/d. but then of course you've got a "new"
problem of needing to find a way to measure current/voltage so that you
can calibrate the pic and it's sensor ... which is the same problem you
started with haha.

maybe the OP could borrow a data logger or multimeter/laptop setup ...
that's what most people do when they need an expensive tool, borrow it,
or rent it