I guess that kerosene and both ethanol and denatured alcohol
(methanol) should have been readily available, though the quantity
needed for what sounds like a substantial rocket booster might be
problematic. If you want to really get a subplot with drama and/or
comic relief going, set it in Chicago, since the timeframe is the
early days of Prohibition...

Here's a picture of a 1920 car battery:
http://cgi.ebay.com/1920-Ad-Ray-Car-Battery-Batteries-Ypsilanti-Michigan_W0QQitemZ230315446314QQcmdZViewItemQQimsx Z20081221?IMSfp=TL081221113007r19182#ebayphotohost ing

That leads me to a suggestion of looking at contemporary newspapers
and old movies to get a feel for the technology of the era and what it
looked like. A next phase of research would involve finding the
right museums or big-city libraries. Old encyclopedias and technology-
enthusiast magazines are good sources; for example, this link suggests
that in the US, 6V was pretty common, whereas if your story is set in
Italy, you're looking at 12V:
http://books.google.com/books?id=yQcoAAAAYAAJ&pg=PA999&lpg=PA999&dq=1920+c ar+battery+voltage&source=web&ots=NXKtoMHGmT&sig=m tNMGbW7G6zvcJljnzogGDzb9Ec&hl=en&sa=X&oi=book_resu lt&resnum=2&ct=result

Note that lead-acid batteries were a pretty familiar technology by
1920. Electric cars had been neck-and-neck contenders with other
propulsion technologies since almost the earliest days of the
horseless carriage, though they were in decline by 1920; World War I
submarines had banks of batteries and ran on electric power while
submerged; etc. Electric self-starters were getting common enough by
then.

As for the laptop chargers, those of Earth at the dawn of the 21st
century can usually auto-adjust to 110-220 V a.c. 60 Hz wall current.
There was still a fair bit of 25 Hz and some other frequencies
floating around, so you'll have to look up what would have been used
in Chicago, or Italy (I think they may have had 42, 50, or 60 Hz).

Anyway, whether AC or DC (the history of rural electrification also
factors in) you can see plenty of opportunity for either major plot
influences or grace notes in the search for computer power, so good
luck!

--Joe

Ad absurdum per aspera wrote:
It looks like Italy is it.

We're going to start shooting the indoor scenes next month; despite the
fact the plot and story isn't 100% finished. We'll probably shoot
different versions of the same scene more than once.
They decided to put me in the middle - I'm going to be in the craft when
it gets shot back. That was unexpected.

Any road warrior of th early 21st century carries with him an inverter
or a car cigarette lighter adapter. Today we call them power sockets.
They generally convert something like 12vDC to 15vDC to whatever the
laptop uses - eliminating the need for an inverter.
Look on ebay and search for magsafe and airline.
The current script is the characters will use the DC from the batteries
wire it to an airline/car adapter and then to the laptop.


I was thinking of maybe having a laptop power brick blow out, or damage
one of the laptops - this way it takes longer to do the calculations.