Last time a car went dead in the garage, my wife's Fit, I hacked up a
> charger from an old DSL wall-wart and a sabre saw as a series current
> limiter. The garage geometry makes it essentially impossible for us to
> push a car uphill to the street to jump it. Now The Brat left her Echo
> in the garege for a month or so and it went dead, too. So I figure
> it's time to buy a real charger. Went to Kragen Auto Parts and bought
> two (one for here, one for Truckee) chargers. They are all "smart
> chargers", namely switchers with electronics, these days.
>
> The battery is really dead, 1.8 volts. The first charger hums and
> outputs nothing. Tried the next one: it hummed for maybe 3 seconds
> then sparked and smoked inside.
One month? Dead battery (1.8V)? Forget it. Buy a new battery.
In the meantime, hook up a fresh battery through a test lamp and make sure there isn't a short somewhere in the car's electrical system. It may just be a dome light left on, but I've parked cars with clocks, radio memory and assorted microprocessors always on. They start just fine after a month.