On Tue, 11 Oct 2005 23:19:43 GMT, Veggie wrote:

I have a car with a battery that is completely discharged (accessory
left on for over 24 hours). Read 0 volts.

What is the best way to remedy this?

a) jump start - it seems to not be a good option as it dumps high
current into the dead battery. If you're on the road somewhere, sure,
you need to get going but jump starting seems to be undesirable.

b) put it on a battery charger, one of those 5/10/25 amp ones. If so,
which rate is the best for a completely flat battery?

There seems to be a lot said about sulfate build up on batteries. It
seems to be an unsettled subject on the Net, as many say one thing but
an equal number refute it. One claim in interesting to me- that leaving
a lead acid battery in flat condition for a long time caused sulfate
build up. Is this true, and what is a "long time"? Are we talking
days, weeks, or months?

Charge it using a charger, rate isn't that important unless you do
have alot of sulfation. Then you need to use a really high amp
charger, 40amp or higher, to burn off that sulfation.
You could have it tested at a decent battery shop for sulfation
levels.(and any possible shorted or dead cells as well.)
They'd have a charger designed for reviving problematic batteries as
well.
Jumping it off from flat dead is a no-no, especially with later model
cars with loads of electronics and mainly an electronic altenator.(
You can really do a number on the electronic regulator internalized in
most late model altenators. Burnt diodes, fried control chip etc...
trying to jump start and run with the battery that low.)
Better to remove the battery and get it charged up before running the
electronics off it.
One big reason to go with "old school" auto's if possible, less to go
wrong and rock solid reliability.( a heavy duty marine grade altenator
with a competitive ignition coil and double duty external voltage
regulator. If it's a stick you can just give it a push and you're off
and running.)